2001 AAPG Eastern Section Meeting Abstracts


Recent Gas Discoveries and Activity in the Ordovician Trenton/Black River in West Virginia

 

AVARY, KATHARINE LEE, West Virginia Geological & Economic Survey, Morgantown, WV

 

The discovery by Columbia Natural Resources (CNR) of large volumes of gas in the Upper Ordovician Trenton and Black River limestones in Roane County, WV in the spring of 1999 has led to a flurry of permitting activity. The discovery well, CNR 20097 Frederick C. Parker well (087 4250) was drilled into the Black River and encountered a reported estimated natural open flow potential of 50 MMcfgpd, with a reported rock pressure of 5,750 psi, in an open hole completion from 10,255 to 10,271 feet. A second well in the Cottontree field, the CNR 23975 Juanita Groves et al. well (087 4255) was completed in the fall of 1999. The pay in this well is in the Trenton, at 9,658 to 9,712 feet. The reported natural open flow potential was 28 MMcfgpd, with a reported rock pressure of 4,897 psi.

Over 100 wells in 12 counties have been permitted to the Trenton and deeper zones through March, 2001. The West Virginia Geological and Economic Survey has received well records for a total of four wells, three in Roane County and one in Kanawha County.

Limited production data suggest that these wells do have substantial reserves. Apparently, the reservoirs are located in highly fractured carbonates within the Trenton and Black River. There seems to be a correlation between the location of the wells and the location of the southeast margin of the Rome Trough.

Information on these wells is being made available on the WVGES website, www.wvgs.wvnet.edu in the form of a viewable table, and downloadable spreadsheet and GIS files.

 

The Serpent Mound disturbance of southern Ohio: a structurally complex impact site with hydrocarbon potential from the Ordovician and Cambrian System reservoirs.

 

BARANOSKI, MARK T., Ohio Department of Natural Resources, Division of Geological Survey, Columbus, OH, and WATTS, DOYLE R., Wright State University, Department of Geological Sciences, Dayton, OH.

 

The Serpent Mound disturbance, a recently confirmed impact site, has deeply eroded, folded and faulted Ordovician through Mississippian bedrock exposed at the surface. Of the seven exploration wells that have been drilled into this structure, the two deepest wells reached total depth in the Cambrian Knox Dolomite. Reprocessed seismic reflection data indicate a faulted structural depression extending from the Ordovician Lexington/Trenton Limestone downward into Precambrian basement and is apparently surrounded by a fault-bounded ring anticline. This structural low is very enigmatic because it is approximately coincident with a central uplifted area and localized gravity low. The seismic reflection data also reveal anomalously thin Cambrian Knox Dolomite and Rome Formation beneath the central uplift area. The eastern portion of the Serpent Mound structure holds the most promising structural and stratigraphic traps, which have not been tested. Scattered hydrocarbon shows reported from the Ordovician Lexington/Trenton Limestone and Cambrian Knox Dolomite and Conasauga, Eau Claire, and Rome Formations of southern Ohio and northern Kentucky suggest promise in a largely untested region. These intervals contain the least explored sequence of potential reservoirs in this region and may warrant acquisition of additional seismic data to define prospective locations.

 

 

 

 

 

 

Hydrothermal Dolomite Reservoir Facies (HTDRF) in the Dundee Limestone, Central Michigan Basin, USA

 

BARNES, D.A, and HARRISON, W.B. III, Western Michigan University, Kalamazoo, MI( barnes@wmich.edu)

 

HTDRF is a distinctive carbonate reservoir type that contains major oil and gas reserves worldwide. A well-documented and highly productive example of HTDRF in Michigan occurs in Ordovician rocks of the Albion-Scipio and Stoney Point Fields. The major geological features in common, globally, in the HTDRF are: 1) extensive diagenetic modification of the reservoir rock matrix to a distinct suite of alteration minerals (saddle dolomite and MVT-like mineralization) through hydrothermal processes, and 2) genetic association of HTDRF with complex fault/fracture systems attributed to reactivated, transcurrent basement faults.

Initial petrologic observations, oil field structural mapping, and production characteristics in several Dundee oil fields suggest that HTDRF are important in the west-central Michigan basin. Saddle (hydrothermal) dolomite is a common vug and fracture fill in association with highly fractured, pervasively dolomitized rock matrix. The irregular top of Dundee porosity (top dolomite) structure in the Vernon Field (Isabella CO., MI) for example, is interpreted as the expression of extensive NW-SE, en-echelon, sinistral Riedel shear fractures/faults. These faults and related fractures, some with large vertical extent, were probably fluid flow conduits for dolomizing fluids and hydrocarbon migration on a geological time scale, and are conduits for formation fluid flow (including water) on a production time scale.

Very high initial oil production (thousands to tens of thousands of bopd in some wells) in strong bottom water drive Dundee dolomite fields was typically associated with rapid oil production decline and increase in water production. These fields probably posses dual porosity systems (generally low matrix porosity with high fracture density) that should have major impacts on production characteristics and dictate effective drilling and completion procedures. Careful reservoir characterization, in the context of generic HTDRF properties, should provide guidance in interpreting unusual geological features and formulating exploration, production, and enhanced recovery programs in central basin Dundee fractured dolomite reservoirs.

 

Results of a Horizontally Drilled Hole Within the Dundee Formation: Freeman-Redding Field, Clare County, MI

 

BARRATT, Michael W., Newstar Energy USA, Inc

 

Since 1995, a total of 22 horizontal tests have been drilled through the Dundee Formation in the Michigan Basin. Published results initially indicated a high degree of economic success. A closer evaluation reveals that very few of the horizontal attempts have sustained commercial production over the last five years. Operators drilling future horizontal tests in the Dundee will be able to take advantage of results obtained to date to improve success rates of these tests. An example of a Dundee horizontal well drilled in the Freeman-Redding Field is used to illustrate evaluation and testing methods.

The Freeman-Redding Field, located in Clare County, Michigan has produced approximately 17 million barrels of oil and 2 billion cubic feet of gas from the Devonian, Dundee Formation since its discovery in 1938.

The reservoir rock consists of a porous dolomite underlying a variable thickness of dense, non-porous limestone. Hydrocarbon trapping is provided by 20' to 30' of structural closure at the Dundee. Stratigraphic variations within the Dundee impact productivity of wells within the field.

Results from an 1,800' horizontal hole indicate that rapid variations in porosity and permeability exist laterally within the reservoir rock. Using data obtained from sample cuttings, core analysis, electric and mud logs, and production testing, tentative conclusions were derived to optimize drilling, completion, and evaluation techniques for the drilling of future Dundee horizontal holes.

Placement of economically successful horizontal holes within the Dundee reservoirs in the Michigan Basin depend upon pre-planning, thorough mapping, careful evaluation and a little bit of luck.

 

Results of Surface Geochemistry Survey over the Vernon Field, Isabella County, MI

 

BORNHORST, T.J., WOOD, JAMES R., and CHITTICK, S.D., Michigan Tech. Univ., Houghton, MI

HARRISON, W.B., BARNES, D., Western Michigan Univ., Kalamazoo, MI

Four surface geochemical techniques have been tested at the Vernon Field in support of a demonstration project partially sponsored by the U.S. Department of Energy to detect and recover bypassed oil. The techniques included surface iodine, enzyme leach, microbial and soil gas. The most extensive sampling (350+ samples) was for the microbial oil survey technique in which microorganisms are cultured from soil taken 20 cm beneath the surface. Results from a smaller number of iodine samples (collected from soil within an inch of the surface), headspace soil gases (collected from 1 meter beneath the surface) and selectively extracted trace elements (from the top of the B-horizon) and soil gas hydrocarbons (extracted from soil of the top of the B-horizon) will be presented as well.

The detection of subsurface accumulation of oil and/or gas by surface geochemical techniques is based on microseepage of reservoired hydrocarbons to the surface and has been used elsewhere in combination with other data to reduce drilling risk. Except for the enzyme leach techniques, the surface geochemical signal recorded is transient (i.e. not cummulative) and will respond to changes in the reservoir. Only transient techniques are useful to detect by-passed oil. The microbial anomaly was apical while the others are best interpreted as edge anomalies or halos around the target.

The initial collection of geochemical samples was completed during the summer of 2000 and sampling will be continued during the summer of 2001. The challenge with all of the surface geochemical techniques is definition of anomalies and their interpretation. The cause of the surface geochemical anomaly can be from a variety of depths beneath the surface. The initial results demonstrate that hydrocarbon microseepage from the Dundee reservoir is detectable by surface soil geochemical techniques.


Dinosaur Hunting a Century after the Gilded Age: A Modern

Perspective from the Field

 

CLAREY, TIMOTHY L., Delta College, University Center, MI 48710

 

The great dinosaur rush during the Gilded Age (1870s-1890s) was fueled by competition between rival scientists, principally E.D. Cope and O.C. Marsh. Dinosaur bones were suddenly worth money, prompting the appearance of numerous amateur collectors across the American West. Tales of government corruption, womanizing and scientific blunders were commonplace, making the late 19th Century sound a lot like the late 20th Century. Today, amateurs remain the principal means of dinosaur exploration and discovery. Modern paleontologists can still get caught up in hoaxes, such as the recent Archaeorapter affair. Scientific reputations can still be made with a timely discovery. The sale of Tyrannosaurus "Sue" for over $8 million has again placed dinosaur bones in high-priced demand. Dinosaurs are being bought, sold and marketed by big business.

Participation as an amateur at dig sites can still be both rewarding and eventful. Recent discoveries with the Wyoming Dinosaur Center in Thermopolis, and with the Museum of the Rockies near Choteau, Montana, illustrate the field techniques of the modern paleontologist. The extraction of bones with simple tools and the use of burlap and plaster casts are methods developed over a century ago. Financial reward in these programs is replaced by the thrill of discovery and the opportunity to make a contribution to science. Stegosaurs, brontosaurs and an occasional new species can be just a few brush strokes away. In some ways, history does repeat.

 

 

Use of Desktop Personal Computers to Model Geologic Surfaces and Volumes in Two and Three Dimensions. Tips, Tricks, and Traps.

 

COWEN, TIMOTHY M., Cowen Oil & Gas LLC, Grand Rapids, MI

WAY, G. S., GSW Petroleum Engineering, Allegan, MI

 

Desktop computers can be used to effectively model large spatial datasets in two and three dimensions, providing improved interpretation and visualization of geologic and reservoir parameters. Computer gridding and modeling techniques greatly assist qualitative and quantitative reservoir characterization and provide investigators with low cost geologic modeling solutions.

PC-solutions, however, are not "one-step crank turning", but rather often involve numerous steps of procedure to achieve the desired results of combined geologic interpretative bias with un-biased computer data mapping and numerical grid modeling.

The advanced grid-modeling necessary to achieve this desired effect involves a myriad of techniques used to systematically build accurate 2D structural and stratigraphic surface models, incorporating both regional scale and detailed local scales of investigation. These procedures are the focus of this presentation.

Resulting 2D structural and stratigraphic surface models provide a framework to constrain 3D geologic solid volume (voxel) models. Proper construction of 2D and 3D models yields meaningful and representative quantitative results of volumes and ultimately, reserve determinations if sufficient input data are available.

Further use of this methodology can integrate many other geoscience software solutions including 2D and 3D seismic inversion, seismic attribute analysis, and ultimately transformation of the geological/geophysical models to reservoir simulator environments such as the DOE PC-BOAST (Personal Computer - Black Oil Applied Simulation Technology).

 

 

 

 

Mid-Jurassic Age "Red Beds" of the Michigan Basin

 

CROSS, AUREAL T., Michigan State University, E. Lansing, MI

 

A series of yellow-tan to purplish-red stained sandstones and gypsum beds intercalated in red and greenish-grey shales in the west central Lower Peninsula of Michigan, is clearly identified by palynology as mid-Jurassic in age.

Palynomorphs of late-Mesozoic age in the Michigan "Red Beds" were first reported by Cross and Shaffer, 1964. Later studies in Canada and Europe have made more precise age determination and correlation possible. Presence of pollen of Classopollis in profusion and a diverse mix of podocarp, tsugoid, laricoid, araucarian, cycadeoid, and ginkgoalean pollen indicate Bajocian-Bathonian age.

The "Red Beds" are closely correlated with the Mistuskwia beds of the Moose River Basin of the James Bay Lowland, Ontario, based on pollen from test cores. The palynoflora is similar to that of the Shaunavon and Gravelbourg Formations, Saskatchewan and Alberta, and to Sawtooth and Rierdon Formations, northwestern Montana.

Quarries, and oil, gas and water wells in the vicinity of lonia and Lyons indicate the lonia Sandstone is the basal member of this Jurassic sequence. The "Red Beds" appear to have accumulated in a large, inland playa with internal drainage on a broad, structurally controlled, intermittently reactivated, shallow depression. Absence of acritarchs and dinoflagellates suggest a non-marine origin. However, a brief transgression of an epeiric sea through a northerly channel, and development of a sabkha-like environment on a broad coastal plain of low-relief might be considered.

Midcontinent Interactive Digital Carbon Atlas and Relational Database (MIDCARB)

 

DRAHOVZAL, JAMES A., Kentucky Geological Survey, University of Kentucky, Lexington, KY; WICKSTROM, LAWRENCE H., Ohio Department of Natural Resources, Division of Geological Survey, Columbus, OH; CARR, TIMOTHY R., Kansas Geological Survey, University of Kansas, Lawrence, KS; RUPP, JOHN A., Indiana Geological Survey, Indiana University, Bloomington, IN; SEYLER, BEVERLY, Illinois State Geological Survey, Champaign, IL; and WHITE, SCOTT W., Energy Research Center, University of Kansas, Lawrence, KS

 

The Midcontinent Interactive Digital Carbon Atlas and Relational DataBase (MIDCARB) is a project involving a consortium of five state geological surveys (Illinois, Indiana, Kansas, Kentucky, and Ohio). The goal of this U.S. DOE-funded project is to construct an Internet-based relational database management and geographic information system (GIS) to evaluate the distribution, physical characteristics, and economic parameters of potential anthropogenic CO2 sources and geologic sequestration sites. Potential geologic sequestration sites include oil and gas fields, coal beds, abandoned subsurface mines, unconventional oil and gas reservoirs (including organic shales), and deep saline aquifers.

Although geologic sequestration of CO2 appears very promising, very little detailed work has been done at the state and local levels to assess the real storage potential. MIDCARB will provide both private- and public-sector decision-makers with online access to a sound information base to use in evaluating technologies for CO2 sequestration on a regional and local basis. Completion of the project for the Midcontinent will provide a tool to evaluate the impact of CO2 sequestration on an important region of the country and serve as a model for similar projects in other areas. Digital access to pertinent information will be critical in evaluating CO2-mitigation policies, directing needed research, and understanding the technical, economic, social, and environmental challenges of CO2 sequestration. Carbon sequestration may allow the continued use of fossil fuels in energy systems while addressing the issue of stabilization of atmospheric CO2 levels.

 

Highest Phanerozoic strontium isotopic ratios of Late Cambrian passive margin in New York State, USA: products of continental weathering and orogenesisFRIEDMAN, GERALD M., Department of Geology, Brooklyn College and Graduate School of the City University of New York, Brooklyn, NY; North-eastern Science Foundation, Inc., affiliated with Brooklyn College, Troy, N.Y; P.O. Box 746, Troy, NY 12181

 

The Late Cambrian Sauk Sequence, a passive margin in New York State, is composed predominantly of carbonate rocks that were deposited in discrete provinces: on the shelf the Beekmantown Group includes the Galway Formation, and the Wappinger Group includes the Pine Plains Formation. On the paleoslope the Taconic Sequence is a deep-water deposit and includes the Hatch Hill Formation. The shallow-water carbonates of the Galway and Pine Plains Formation are dolostones, whereas those of the Hatch Hill Formation are deep-water limestones.

Strontium isotopic values of the carbonates are much higher than others determined for the Late Cambrian and are the highest values for the

Phanerozoic and probably for all geologic times. They show the dominance of continental sources of strontium. Continental and groundwater runoff supplied radiogenic strontium to the Late Cambrian ocean. An apparent increase in seawater 87Sr/86Sr values may record rapid unroofing and attendant increased erosion as well as collapse of mountains that had been constructed during the continental collisions that assembled Gondwana during the Pan African and Braziliano mountain-building episodes. As a result of extensive chemical weathering, erosion and high uplift rates seawater 87Sr/86Sr recorded peak values.

Diagenetic alteration may affect radiogenic strontium. In this study petrography, mineralogical analysis, and isotopic analysis were used to interpret diagenesis. These data provided evidence that diagenesis was not involved.

 

Spindletop – The World Changed Forever

 

Gillespie, ROBB, Adjunct - Western Michigan University, Kalamazoo, MI

 

President William McKinley was assassinated in 1901. Theodore Roosevelt succeeded him setting the United States on the path to becoming a global super-power. This rise was fueled by the country’s industrial power, which entered a new phase on January 10, 1901, when

the Spindletop well "blew out" in Texas. Internationally, Spindletop provided Roosevelt with his "big stick," while domestically, it triggered a shift of money and power away from the north to new ventures in Texas.

The Spindletop well, by itself, increased total world oil production

more than 20 percent and increased United States production by nearly 50 percent. After five more wells were drilled, the Spindletop Field could produce more oil in one day than the rest of the fields in the entire world.

Spindletop was a petroleum engineering breakthrough. It proved the worth of the new rotary drilling rig and established many standard drilling practices still in use. Even much of today's common oil field jargon was coined at Spindletop. Geologically, Spindletop was the first oil field discovered on a salt dome structure. This gave credence to ideas about hydrocarbon accumulations, and basic concepts concerning hydrocarbon seals were first envisioned with the success of this well.

Giant oil companies (i.e. - Gulf and Texaco) got their start at Spindletop. Fledgling Texas oil companies (i.e. - Magnolia) blossomed and northern oil companies (i.e. - Ohio-based Sun) grew dramatically in size. They became Standard Oil’s first serious domestic competition.

Oil was now plentiful and cheap. Spindletop confirmed that a mass automobile market could be supported. This in turn soon revolutionized America’s cities and transformed the agrarian society of the 1800s into the industrialized, urbanized society of the 1900s. The world changed forever.

 

 

Dundee Field Production History and Reservoir Performance in Relation to Reservoir Type

 

HARRISON, WILLIAM B., III, Department of Geosciences, Western Michigan University, Kalamazoo, MI

 

Shallow shelf carbonate reservoirs in the Dundee Formation of Michigan are the most prolific oil producers in the basin’s history. Cumulative oil production exceeds 350 million barrels from about 100 fields since the play’s discovery in 1930. The two primary Dundee reservoir types are most easily distinguished by their lithology. One is mainly composed of dolomite the other is predominately limestone. Each of these two main types has two or more subtypes distinguished by depositional fabrics and diagenetic overprints. Although each primary type or subtype of reservoir is generally found in a specific portion of the basin, there are notable exceptions of where these reservoir types are mixed in the same geographic area.

Analysis of initial flow data, cumulative oil production/ decline curves, and water production history provides useful information about reservoir performance in this play. Examination of core samples and conventional porosity and permeability data confirm the reservoir type and subtype for selected fields.

Limestone reservoir types maintain much of their original depositional fabric. The pore structure is dominated by intergranular and intraparticle porosity. Grainstone shoal/sand bodies, patch reef complexes, and vertically and horizontally-fenestral, peritidal, packstones and wackestones are three known subtypes in the limestone reservoirs. IP rates are usually in the 10’s to 100’s of barrels per day. Water production is generally low throughout the life of the field. The drive mechanism is probably solution/expansion gas. Reservoir pressures decline continuously during production.

Dolomite reservoirs may be pervasively dolomitized examples of the same depositional fabrics seen in the limestones, or the more common highly-fractured and mineralized hydrothermal dolomite reservoirs (HTDR). Increased permeability and porosity give the dolomite reservoirs higher IP’s (100’s to 1000’s BBLS/day). Water production is abundant and early in the life of the field and reservoir pressures drop little due to strong water drive.

Additional Factors Brought into play in Hydrocarbon Exploration in the Southern Appalachian Foreland Fold-Thrust Belt

 

HATCHER, ROBERT D., JR., University of Tennessee, 306 Geology Building, Knoxville, TN 37996-1410

 

Most of the factors that are important in hydrocarbon accumulation in undeformed basins and continental margins -- stratigraphic framework, porosity, thermal maturity, fluid systems, and basement features -- are also important for accumulation in foreland fold-thrust belts. In addition, factors related to foreland fold-thrust belt development come into play. These include fault- and fold-related structures, fracture arrays that form in response to deformation, deformation-related porosity changes, and deformation driven fluid migration. Traps may be filled or emptied depending on their integrity prior to, during, and after deformation. If migration occurs before deformation, the hydrocarbons may survive and be trapped. If migration occurs after deformation, the hydrocarbons may not survive.

Exploration options in the southern Appalachian foreland fold-thrust belt have been widened by the documenting of an Ordovician source for oil in the Swan Creek field. Structural options have also been increased by the footwall occurrence of hydrocarbons there as well. With this new discovery, the southern Appalachian foreland fold-thrust belt should no longer be written off as a barren region.

 

Stratigraphic Cross Sections Through Niagaran Strata of the Central Appalachian Basin: A Regional Perspective of the Lower Silurian Oil and Gas Accumulation

 

HETTINGER, R.D., U.S. Geological Survey, Denver, CO; and

RYDER, R.T., U.S. Geological Survey, Reston, VA

 

Six new cross sections show facies transitions and gas-bearing intervals in the Lower Silurian regional oil and gas accumulation (LSRA) in New York, Ohio, Pennsylvania, and West Virginia. Featured are the "Clinton" sandstone in Ohio and the Medina Group in Pennsylvania and New York. Also shown is the equivalent and more proximal Tuscarora Sandstone of Pennsylvania and West Virginia. The cross sections provide excellent perspectives of depositional variability across the basin-center and conventional/hybrid parts of the LSRA.

In contrast to most investigations that associate deposition of the "Clinton", Medina, and Tuscarora with a single transgressive-regressive marine cycle, we suggest two transgressive-regressive marine cycles (sequences 1 and 2) and the transgressive phase of a third cycle in sequence 3. We suggest three sea level lowstands existed during the Rhuddanian Stage, each followed by a sea level rise that culminated in a highstand. Unconformities associated with the lowstands include the Cherokee unconformity at the base of the Whirlpool Sandstone, and two unnamed unconformities in the middle and upper part of the "Clinton"/Medina interval. Paleovalleys were backfilled with fluvial or tidally-influenced sediment during the initial phase of each sea level rise, and thick deposits of estuarine strata overlie the uppermost unconformity.

Most sandstone in sequences 1-3 yield commercial quantities or shows of oil and/or natural gas. Wells with the highest initial yields do not consistently favor any particular facies or sequence. However, some wells have greater gas yields from fluvial and estuarine sandstone in sequences 1 and 3, perhaps caused by the dissolution of feldspar-grains derived from eastern highlands, and an accompanying increase in secondary porosity.

Exploring for Hydrothermal Reservoirs in the Applachian Basin

 

HICKMAN, ROBERT G. Structural Solutions, Sugar Land, TX, KENT, W. NORMAN,Kent GeoScience Associates, Richmond, TX, MARTIN, JEFF R., and ODEGARD, MARK E., GETECH, Stafford, TX

 

Fractured hydrothermal dolomite reservoirs in the Trenton-Black River Group have produced large amounts of oil from the Bowling Green fault trend of Ohio, the Albion-Scipio and Stoney Point fields of the southern Michigan basin and numerous smaller fields in southern Ontario and Ohio. Recent high-productivity gas discoveries in similar reservoirs in New York and West Virginia have spurred exploration interest for these types of accumulations in the Appalachian basin.

All of these fields are long and narrow, reflecting the role of faults in channeling the dolomitizing fluids and focusing hydrocarbon migration. The reservoir rock consists of vuggy, brecciated, locally cavernous dolomite. Lateral and top seals are provided by the unaltered formation that consists of tight, platform limestones with minor argillaceous interbeds. Secondary minerals and fluid inclusion data indicate the dolomitizing fluids were hot, saline fluids similar to those responsible for formation of Mississippi Valley type lead-zinc deposits. Circumstantial evidence suggests that the reservoirs formed in Late Paleozoic time. Typing of oils indicates probable derivation from interbedded Ordovician source rocks. In the Appalachian basin, dolomitization is associated with reactivated faults related to earliest Paleozoic rifting of Laurentia or with Grenville-age structures.

In the past, deliberate exploration for this type of accumulation has not been highly successful. However, modern seismic techniques now provide keys to prospect identification. Integration of publicly available geologic maps, potential field maps, digital terrain models, well and seismic data, with a conceptual exploration model provides a cost-effective means to identify high-graded, focused exploration areas. The focus areas can be used to maximize a company's seismic acquisition budget to acquire seismic data that can indicate prospect level evidence of fractures and dolomite reservoir development.

 

 

The Use of Microgravity Data to Increase the Success of Niagaran Reef Exploration in the Michigan Basin

 

HINKS, ALAN W., Westshore Consulting, Muskegon, MI

SCHULZ, ROBERT L., Westshore Consulting, Muskegon, MI

 

Although the Michigan Basin is considered a mature hydrocarbon play, new Niagaran reef reservoirs are regularly discovered. A significant reason that a number of reefs remain undiscovered is because glacial drift and underlying scoured bedrock limit the signal-to-noise ratio of geophysical methods. Seismic methods are limited by energy attenuation in drift and scattering of energy at the scoured drift/bedrock contact. Bouguer gravity data allows subsurface density variations to be identified, and has been used successfully to locate reefs, but is severely limited by scouring on the drift/bedrock contact.

Microgravity data is precise, densely sampled Bouguer gravity data that is being used to improve exploration success. The shallow density variations caused by drift-filled scours produce high frequency gravity anomalies, while deeper density variations cause lower frequency anomalies. Because microgravity data samples the high frequency content of gravity anomalies, gravity anomalies caused by scours can be identified by their frequency content.

Once scours are identified, that information can be used to highlight areas where seismic data should be questioned or receive additional processing and interpretation. Additionally, the identification and segregation of high frequency gravity anomalies often allows deeper-sourced broader gravity anomalies, like those caused by Niagaran reefs, to be reliably identified. Once the probable source of gravity anomalies is identified, the direct identification of Niagaran reefs from microgravity data can aid in the development of prospects in areas where seismic data is expensive and/or quality seismic data cannot be acquired.

 

 

In Situ Biosurfactant Production at a Petroleum Refinery

HUDAK, ANDREW J., Western Michigan Univ., Kalamazoo, MI CASSIDY, DANIEL P., Western Michigan Univ., Kalamazoo, MI

 

The subsurface at the former Crystal Refinery in Carson City, Michigan has been impacted with petroleum products for several decades. Since many genera of microorganisms produce biosurfactants during growth on petroleum compounds, a study was conducted in the smear zone at the former Crystal Refinery to determine whether biosurfactants were produced in situ by the prevailing microorganisms in impacted areas. Microorganisms were identified in cultures obtained from soil samples using fatty acid methyl ester (FAME) analysis. Surface tension was measured in filtered ground water samples from wells from hydrocarbon impacted areas and from control wells. Groundwater samples were concentrated in a rotary evaporator. Rhamnolipid surfactant concentrations were measured in derivitized samples using HPLC.

Results showed that the most populous species in hydrocarbon impacted areas was Pseudomonas aeruginosa, which is known to produce rhamnolipid surfactants. Surface tension measurements in groundwater samples from impacted wells decreased from above 65 dynes/cm to roughly 30 dynes/cm as groundwater was increasing concentrated in the rotary evaporator, indicating that surfactants were present. In contrast, groundwater samples from control wells showed no such decrease in surface tension. HPLC analysis showed that monorhamnolipids and dirhamnolipids were present in measurable amounts in the impacted wells, but were absent in the control wells. These results document in situ biosurfactant production from indigenous microorganisms.

 

Computer-enabled Exploration using the GeoGraphix Discovery Plus Products

 

JACARUSO, TOM and LANGE, MARTIN, GeoGraphix, Inc., Denver, Colorado

 

Improvements in software and hardware technology have significantly enhanced the efficiency, accuracy, and productivity of the E&P geoscientist. Technology investment often results in improved success ratios, reduced finding costs, and ultimately provides a competitive advantage. The cost of adopting such technology is typically pennies of the total exploration dollar, and provides recurring value as software and user expertise evolve.

The breadth of software application integration will be presented in four-phase case study of an acquisition with field development and exploration upside.

  1. An asset team analyzed lease, well, production, and 2D seismic data relative to a field development and adjoining acreage purchase with integrated software. Generation of basemaps, cross sections, and 2D structure and attribute mapping, resulted in drilling an infill location and acreage purchase.
  2. The second phase focused on a deeper play, integrating additional 2D seismic and 1D forward log modeling. A deep prospect, based on models and seismic attribute extraction, was drilled successfully, and opened a new play within this sub-basin.
  3. The asset team recommended 3D seismic acquisition, and with integrated geologic control, mapped, proposed and drilled five more wells in the play. The program had a 60% success, and management demanded quantifiable post-mortems.
  4. The fourth phase relied on petrophysical analysis of the pay interval, and correlation of reservoir character with 3D amplitude, to explain the drilling results. This analysis provided a level of confidence to accurately predict the gas volumes on a final prospect, to date the best well of the deep prospects.


 

The Michigan Basin is Thermal in Origin

 

KOMINZ, MICHELLE A., WERKEMA, DALE, BARNES, DAVE, HARRISON, III, WILLIAM and KIRWAN, ERIC; Western Michigan Univ., Kalamazoo, MI; and MALIN, MATT, Foothill Engineering Consultants, Golden, CO

 

Three deep wells were backstripped to determine the tectonic history of the Michigan Basin. These wells, the Miller Victory , the Wolverine Patrick and St. Norwich, and the Hunt Martin, form a cross section in central Michigan. Recent detailed petrologic analyses and sequence interpretation of the lower Paleozoic portion of these wells allowed accurate ages, lithologies and paleoenvronments for input. Recent revisions of the lower Paleozoic biostratigraphic time scale were applied.

Backstripping revealed the typical episodic subsidence which has been reported for the Michigan basin by many authors. However, we focus here on the new data for the Cambrian and Ordovician portion of the record. When a thermal curve is fit to this portion of the data for each well, the difference between this curve and observed subsidence in water is remarkably similar in all three wells and remarkably similar to sea-level estimates derived by the same method in the Great Basin of western North America. These results strongly suggest that the Michigan Basin did have a thermal origin and that global sea-level changes were recorded in Michigan Basin sediments.

 

 

High Resolution Geologic Mapping of Northeast Southern Michigan

 

KRIST, FRANK, JR., Michigan Department of Natural Resources, Roscommon, MI; and

BLACK, TYRONE, Michigan Geological Survey, Gaylord, MI

 

Improved geologic mapping is possible through the integration of dissimilar data and enhanced processing capabilities found within Geographic Information Systems (GIS). This was demonstrated in part of Alcona, Alpena, Montmorency, and Presque Isle counties in northeastern Lower Michigan. Bedrock topography, drift thickness, bedrock geology, and formation structure surfaces were interpolated from various well data using the TOPOGRID command within the ARC/INFO GIS environment. The TOPOGRID command can generate a "hydrologically correct" topographic map that depicts the bedrock surface including the buried channels found on that surface. These channels are significant for aquifer delineation and protection, and have affected Antrim Shale gas production. Tolerance settings and the ability to turn off the drainage enforcement algorithm within TOPOGRID enable surfaces to be generated for bedrock formed under various conditions.

Michigan’s MIR oil and gas well database was filtered for data on formation top elevations and integrated with water well, outcrop, and geologic test hole data. Errors within the MIR database include multiple formation depth picks, missing elevations, and typos. A semi-manual process of reiteration between the well data, and the simulated structure and geologic surface maps was used to crosscheck and improve the accuracy of the interpolated maps.

 

Three-Dimensional Reservoir Architecture and Improved Oil Recovery in a Deltaic Depositional System

 

LEETARU, HANNES E., Illinois State Geological Survey, Champaign, IL

 

Centralia Field, located in Clinton County, Illinois is a good example for the potential of recovering additional oil from mature fields. Most of the production from the Mississippian Yankeetown (Benoist) Formation. The field has a unique database of 37 wells with whole core, 60 wells with core analyses, and over 90 wells with digitized wireline logs.

The three-dimensional sandstone architecture of the Benoist reservoir in Centralia Field shows significant lateral and vertical reservoir compartmentalization as a result of being deposited in a coastal plain deltaic system. The sandstone architecture is dominated by narrow (less than 1500 ft wide) upward coarsening northeast-trending sandstone bodies that are interpreted to be distributary mouth bars. Sandstones with abundant impermeable shale and limestone beds dominate areas between the sandstone bodies. The impermeable intervals are rarely continuous over more than 800 acres.

The northeast trending sandstone bars produce an anisotropic pattern during waterflooding of the Benoist reservoir. The most likely candidates for bypassed oil are located in the interbar areas. These isolated interbar reservoir compartments would have been only partially drained by the currently producing wells.

The Evidence for Pinnicle Reef Growth in Kalamazoo and St. Joseph Counties, Michigan

 

LENTZ, JAC E., El Paso Energy, Detroit, MI

 

Oil and gas production from Niagaran aged pinnicle reefs in the Michigan basin has been prolific and well studied over the past four decades. Here, production has been from the reef itself where they are sealed by Salina aged evaporites. Less well known, but directly attributable to Niagaran reef growth is the Traverse Limestone oil production from the East Pullman pool in southwest Michigan’s Allegan County. The closure in this pool is a result of drape over a very tall reefal buildup. The Salina evaporites are not present here. A few other examples of reef induced closure (also Traverse reservoirs) are known in the Michigan basin at a handful of locations (also Traverse reservoirs) in the southern reef trend. In the Illinois basin all production related to Niagaran reef growth is found in reservoirs above the reef. The Salina evaporites are absent, but reef induced closure exists in the younger rocks.

Geochemical data, subsurface mapping and seismic data have been utilized to identify an area of reef growth similar to that found in the Illinois basin, or, like that at the East Pullman field location. That is to say, an area lacking reef sealing Salina evaporites, but with the reef inducing closure on younger formations, themselves being sealed. This area, centered on the Kalamazoo-St. Joseph County line, is sparsely explored and has been widely believed to be absent of pinnicle reef growth.

Compelling stratigraphic, seismic, and drilling evidence has been assembled which supports the postulation of pinnicle reef growth in this area.

 

 

Epigenetic Dolomitization and MVT Mineralization in Paleozoic Rocks of Eastern Wisconsin: Implications for Regional Fluid Flow

 

LUCZAJ, JOHN A., Department of Geosciences, Western Michigan University, Kalamazoo, MI 49008

 

Paleozoic sedimentary rocks in eastern Wisconsin preserve a pervasive hydrothermal signature and contain abundant epigenetic dolomite and ubiquitous trace Mississippi Valley Type (MVT) mineralization. A similar sequence of mineralization is present throughout the region in rocks ranging in age from Early Ordovician through Late Devonian. Petrographic and geochemical evidence suggests a genetic link between the massive dolomite, MVT minerals, and K-silicate minerals in these rocks. A similar sequence of mineralization exists in Ordovician rocks of western lower Michigan, suggesting a related origin. Constraints were placed on the conditions of water-rock interaction using fluid-inclusion methods, cathodoluminescence and plane light petrography, isotopic analyses (C, O, S, and Pb), and organic maturity data. Homogenization temperatures of two-phase brine inclusions in dolomite, sphalerite, and quartz range between 65 and 120˚C. Freezing data suggest a Na-Ca-Mg-Cl-H2O fluid with salinities between 13 and 28 weight percent, NaCl equivalent. Late calcite and barite precipitated below ~ 50˚C. Existing dates on authigenic K-feldspar and illite indicate the timing of water-rock interaction to be 380 to 322 Ma. Stratigraphic reconstructions and Devonian vitrinite reflectance (Ro = 0.5 to 0.62%) indicate low thermal maturity for these sediments and are consistent with short-term heating rather than long-term sustained burial. The data are best satisfied by a model in which fluids moved out of the Michigan basin into eastern Wisconsin during the Middle Paleozoic and were responsible for massive dolomitization, MVT mineralization, and K-silicate mineralization. Evidence supporting this hypothesis includes: 1) similar paragenesis in eastern Wisconsin and western lower Michigan, 2) regionally correlative CL zoning in dolomite, 3) a regional sulfide cement horizon in the St. Peter Formation, and 4) late migrated oil geochemically similar to Devonian Michigan basin oil. Mechanisms capable of forcing warm brines out of the Michigan basin are unclear, but may involve gas-displacement or long distance topography-driven fluid flow along regional aquifers.

 

The Occurrence and Exploration for Reefs in the Devonian Dundee Formation

 

LUEBKING, GLEN A., Savannah Exploration, Inc., Littleton, Colorado

 

The ontogeny of a petroleum basin is based upon multiple cycles of creative geologic thought culminating in the exploration of the geologic concept (i.e. the wildcat well). The exploration is then followed by intense periods of exploitation of the newly found resources. The Michigan Basin has exhibited at least seven Exploration/Exploitation cycles and they are:

 

Shallow Petroleum (Lambton County, Ontario)

Ordovician Carbonates (Ohio and Indiana)

Central Basin Mississippian and Devonian Structural Play (Michigan)

Ordovician Carbonates (Michigan)

Silurian Niagaran Reefs (Michigan and Ontario)

Ordovician Clastics (Michigan)

Devonian Antrim Shale (Northern Michigan)

 

The Michigan Basin is poised for its eighth cycle of exploration activity and a petroleum renaissance. This eighth cycle is the exploration of the Central Basin Province, not for structures as has been done in the past, but for shallow Mississippian and Devonian stratigraphic targets. This paper will focus on reef development within the Reed City Member of the Devonian Dundee Formation.

The reef facies has produced from at least two fields in the Michigan Basin. It appears that reef development of up to 53 vertical feet can be documented and it is hypothesized that reefal growth could very well exceed 100 feet in thickness.

As explorationists, we must always remember that creative geologic thought and concepts will find significant hydrocarbon resources in mature petroleum provinces.


 

Regional Depositional Control on Dundee Reservoirs in the Michigan Basin

 

Maness, Timothy R., Maness Petroleum Corporation, Mount Pleasant, Michigan

 

The Devonian Dundee Formation in the Michigan Basin contains several distinct reservoir modes. Porosity types range from primary limestone to secondary dolostone in normal marine to restricted depositional environments. Depositional facies have a north-south strike and thus reservoir types are partitioned east to west across the central basin.

While the top of the Dundee is readily correlated over much of the basin, the base is less definite. Most workers pick the base at the first (uppermost) anhydrite bed in the Detroit River Group. However, the first anhydrite bed at one locale may not correlate with the first anhydrite bed at another, confounding interpretation. Stratigraphically lower marker beds can be correlated and help unravel lower Dundee/upper Detroit River depositional relationships.

Dolomitization is key for some of the reservoir types. Geologists have long debated different mechanisms for dolomitization in general and the Dundee in specific offers ample opportunity to discuss competing models. The process of hydrothermal fluids percolating through localized faults and fractures is often invoked to explain dolomitization of the Dundee’s Roger City Member, but a regional perspective suggests that alternative models better fit the distribution of dolostone.

Recently, Dundee reservoirs have been the focus of efforts to exploit bypassed oil. The potential for significant remaining recoverable reserves has been largely overstated, particularly in dolomitized Rogers City Member reservoirs. Field studies indicate that 60-70% of the original oil in place has been recovered in most of the pools. These water-drive reservoirs had very efficient recoveries despite the lack of modern production practices.

Still, the Dundee offers opportunity for explorationists. Careful study of existing fields may result in profitable infill drilling and solution-gas reservoirs have potential for secondary and tertiary recovery. New fields remain to be found with improved technology and a commitment to drill.

Where in the World is the Carmen Sandiego A1-36 Well?

(Positional Accuracy in Digital Mapping)

 

MANESS, TIMOTHY R., Maness Petroleum Corporation, Mt. Pleasant, Michigan

 

Maps are critical to the oil and gas industry. Geo-scientists generally have not had to concern themselves with fundamental mapping parameters such as ellipsoids, datums, and projections. Indeed, such matters were rightly viewed as arcane when oil and gas mapping was done manually, based on a single local standard, and conventional surveying techniques were used for collecting data and staking wells. Map ignorance is no longer bliss. Changes in data acquisition techniques, newly refined global reference systems, and widespread use of digital data sets make it imperative that geo-scientists be mindful of how maps are made.

Failure to convert disparate data sets to a common reference system can result in interpretation errors or staking a well in the wrong location. Large errors will probably be readily detected and corrected, but smaller yet still significant ones pose potentially greater problems. For example, data collected with the Global Positioning System (GPS) is slightly shifted with respect to older topographic maps.

Standards are useful, but the same standards may not be appropriate for different organizations or projects. More important is the explicit recognition of the system used and ability to move data between systems. Fortunately, software is readily available to handle data conversion. A general understanding in the oil patch of the commonly used map schemes will minimize problems.

 

 

 Exploration and Drilling on Lake Erie: Opportunity and Challenge for New York

 

MARTIN, JOHN P., New York State Energy Research and Development Authority, Albany, NY

 

Lake Erie is volumetrically the smallest and by far the shallowest of the five Great Lakes. Though small in stature, it is the only lake currently hosting offshore natural gas drilling and production. Production began in 1913 in the waters of the Province of Ontario, Canada, where there are now approximately 800 offshore wells. The majority of this offshore development lies in an area adjacent to New York’s Lake Erie waters. Natural gas is produced from the Silurian Medina Group, a sandstone complex that lies approximately 1,500 ft below the lake bottom. There has been recent interest shown in the deeper Ordovician Trenton/Back River carbonates, fueled by onshore success in both Ontario and New York. These reservoirs are formed in zones of hydrothermal dolomitization.

Clearly, the lack of activity on the New York side of Lake Erie cannot be attributed to poor geology; instead, the barriers to development are institutional in nature. New York State statute allows for the leasing and production of natural gas under the waters of Lake Erie. However, numerous agreements between the governments of the Great Lakes states has created a defacto moratorium on exploration in New York waters. Before a change in the moratorium can be considered, several key issues must be addressed, including the lack of production infrastructure, no existing leasing program, no state regulations for offshore drilling, and potential adverse ecosystem considerations. At least seven federal and interstate agencies, four state agencies, and numerous local governments will be involved in any decision to allow drilling.

 

 

A New Oil and Gas Fields Geographic Information System for Ohio

 

MCDONALD, JAMES, WELLS, JOSEPH G., RILEY, RONALD A., and WICKSTROM, LAWRENCE H., Ohio Department of Natural Resources, Division of Geological Survey, Columbus, OH.

 

A new geographic information system (GIS) has been constructed using the data from the 1996 Ohio oil-and-gas-fields maps. This new GIS will be linked to the state’s oil-and-gas-well data system, RBDMS (Risk-based Data Management System), and oil-and-gas production database, POGO (Production of Oil and Gas in Ohio). The combination of these information systems will allow new types of mapping and analysis of the state’s oil and gas information that were heretofore either cost prohibitive or just not possible.

The oil-and-gas-fields GIS contains all of the known oil-and-gas fields, organized by producing formations. The associated attributes contain field/pool-based statistics (where available) such as average depth, lithology, porosity, cumulative production, and type of production (gas, oil, combination). By linking this system in the future with RBDMS and POGO, it will be possible to gather additional statistics as more data are gathered or new wells are drilled. There are also plans to make the oil-and-gas-field outlines dynamically "grow," or new fields be added, as drilling continues in the future.

As one of its first applications, this new GIS is being used as part of the Ohio Division of Geological Survey’s research into CO2 sequestration. By combining the CO2 production data and the locations of large stationary CO2 sources with the oil-and-gas-fields GIS, analyses are being developed to discern the best candidate fields for CO2 enhanced recovery, determine the CO2 sequestration storability of depleted oil-and-gas fields, and determine the economics of carbon sequestration in Ohio.

 

 

Lithofacies Description and Reservoir Characterization of a Niagaran Pinnacle Reef, Macomb County, Michigan

 

MESCHER, PAUL, Geological Resources Co. and

SCHULTZ, DOUGLAS J., Veritas DGC Inc. Exploration Services.

 

Reservoir characterization and lithofacies description of a continuous core from the Silurian "Brown Niagaran" (Guelph Formation) pinnacle reef and the overlying Salina Group evaporites and carbonates (A-1 and A-2 Formations) show that these formations contain a variety of depositional facies with variably developed reservoir quality, reservoir geometries, and seal capability. Acquisition of a whole core provided detailed depositional facies information and petrographic data for an analysis of both the reservoir facies and reservoir seals within the reef complex. This data was used to examine the interrelationships of lithology, pore types, rock properties from core analysis, and log data. This geological information was used to help delineate the pinnacle reef geometry and identify the edges of the very steep reef flanks in the subsurface.

The pinnacle reef portion of the cored interval ("Brown Niagaran" Guelph Formation) consists of several depositional cycles that include the reef core facies, overlain by reef detritus (storm apron) deposits, and followed by intra-reef deposits. The reef core lithofacies is comprised of variably developed encrusting stromatoporoids, digitate branching stromatoporoids, hemispherical stromatoporoids, and corals. These rocks contain intercrystalline, skeletal moldic, intraskeletal, and fracture pores. Geopetal fill, in combination with exposure surfaces observed in the core, indicate that karst processes may have created cavernous pores in some portions of the framework reef core – further substantiated by the lost circulation zone at the base of the reef core facies at the bottom of the cored interval. The reef detritus facies, consisting of burrowed dolopackstone and dolowackestone with floating clasts of eroded reef debris, has porosity that is characterized by intercrystalline, fine skeletal moldic, fracture and solution vug pores. Intra-reef deposits include burrowed skeletal peloidal dolopackstone and dolowackestone that exhibit geopetal fill in some skeletal moldic pores, as well as open intercrystalline and intraskeletal pores. Because of the mud-rich character of this facies, the intra-reef deposits have fewer fractures and consequently lower permeability.

An argillaceous, stylolitic weathered surface marks the contact of the "Brown Niagaran" with the overlying Salina Group carbonates and evaporites. The A-1 carbonate consists of shallow subtidal, algal doloboundstones and dolopackstones that represent the flooding of the reef. It includes a thin interval of imbricated flat pebble conglomerate that represents rip up clasts derived from desiccated polygons. Commonly considered a seal, porosity in the A-1 interval consists largely of poorly connected intercrystalline pores. However, a basal dolopackstone in the A-1 also contains a combination of intercrystalline pores and relic interparticle pores, and it may be considered a potential reservoir. Coastal sabkha deposits of the A-2 Evaporite and A-2 Carbonate units (main reservoir seals) include anhydritic doloboundstones, enterolithic anhydrite, algal mats, peloidal dolomudstone, and other features indicative of deposition in supratidal to evaporative lagoon environments. Porosity in the sabkha deposits is limited to poorly interconnected microcrystalline voids resulting in low permeability.

 

Natural Gas Storage in a Southeastern Michigan Pinnacle Reef

 

METZGER, FREDRICK W. and ROWAN, MATTHEW C.;

Michigan Consolidated Gas Company

 

In 1992, Washington 10 Storage Corporation and Michigan Consolidated Gas Company, both affiliates of MCN Energy Group (soon to be DTE Energy), began planning for conversion of a Niagaran gas field to natural gas storage. The initial planning and design led to regulatory approval in 1994. Market conditions resulted in a delay in final design and construction until 1997. By that time rapid growth in Washington Township, Macomb County, 30 miles north of Detroit, caused the engineering team to re-evaluate the development plans.

The initial discovery well for Washington 10 was drilled in 1969 and production began later that year. By 1998 over 95% of the original 53 Bcf of gas had been produced from 23 wells scattered throughout the Village of Romeo and Washington Township. Initial storage plans included re-completing 17 original wells and drilling 13 new vertical wells. However, with the growth of the community and MichCon’s positive experience with drilling horizontal wells in central Michigan, this plan was deemed impractical and too costly. As a result, the Reservoir Engineering Department recommended drilling directional wells from four surface locations. This plan would maintain the 41.7 Bcf of working volume and 800 MMcf per day peak withdrawal requirements, while reducing the number of wells, limiting the amount of pipeline and the amount of surface acreage.

Fourteen horizontal wells were drilled over a 7-½ month period. The use of two drilling rigs reduced the project time by 3-½ months. Detailed pre-drill planning and review of multiple drilling scenarios allowed the project team to make rapid informed decisions during the drilling operations. On-site drilling supervision resulted in immediate decision-making and saved considerable costs. The depleted state of the reservoir required that the reservoir section of each well be drilled with air and foam. Initial plans were to drill the reservoir section with a downhole motor; however, experience on the initial well caused the drilling team to change to a combination fluid and air-foam system. Fluid was utilized until the desired angle was achieved or the fluid loss exceeded a maximum range, a lock assembly was then employed and an air and foam system was used to total depth. This method proved very successful, and all remaining wells were completed using this technique. Flexibility and teamwork resulted in a project that was completed on time and under budget.

Drilling directionally from multi-well pads provided the geologic challenge of identifying the flanks of very steep pinnacle reefs. Drilling at a high angle through alternating sequences of carbonate, salt and anhydrite before encountering reef rock made the determination of casing point at the top of the reef difficult. The anhydrite is considerably thinner at the flanks, and directional drilling does not provide optimal samples. Picking the casing point became a team effort by combining the expertise of geologists, engineers and drillers. Comparison of the pre-drill geologic maps with the post drill interpretation shows remarkable similarity. The added well control enhanced the definition of the flanks of the pinnacle reefs and the downhole logs proved that the reef top was picked with great consistency.

 

Geology of the Calvin Impact Structure, Cass County Michigan

 

MILSTEIN, RANDALL L., Oregon State University, Corvallis, OR

 

The Calvin structure involves large-scale and intense structural deformation within a limited area of circular shape. Lithologic and structural evidence suggests the feature resulted from a single highly localized release of tremendous energy. Speculation as to possible origins of such a large-scale explosive structure include both endogenetic and exogenetic processes.

Eight characteristics of the Calvin structure lend support to origin by impact. The structure exhibits: 1) morphological characteristics of complex impact craters in sedimentary targets; 2) recognized relationships between depth, diameter, and structural uplift used to identify surface impact craters; 3) geophysical patterns analogous to those of recognized impact craters with similar lithologic components; 4) a polymictic microbreccia; 5) quartz grains exhibiting single and multiple sets of decorated shock lamellae, Böhm lamellae, rhombohedral cleavage, and radiating concussion fractures; 6) no igneous or hydrothermal mineralization associated with the structure; 7) time synchronous black metallic spherules, similar to those associated with meteoritic ablation and impact ejecta, in close proximity to the structure; and 8) a necessary energy release for structural origin of at least 5.9 x 1018 J of energy, without development of magma or any igneous material.

The identification of astroblemes in the subsurface is rare. Comparison of the Calvin structure to known or suspected Complex impact craters suggests consistent structural and physical analogues. Although a considerable body of interpretive geophysical and structural data favors an impact origin for the Calvin structure, it is the identification of shock-metamorphosed quartz that confirms the structure as an Ordovician impact crater.

 

3D Characterization of Manlove Field, a Cambrian Mt. Simon Gas Storage Field in Central Illinois

 

MORSE, DAVID G. and MILLER, RANDY W, Illinois State Geological Survey, Champaign, IL

 

Manlove Field, a 150 BCF aquifer gas storage field in Champaign County, Illinois, consists of an anticlinal closure reservoir in the Cambrian Mt. Simon Sandstone with a sealing caprock formed by the overlying Cambrian Eau Claire Formation. The upper Mt. Simon is about 50’ thick and includes four sandstone facies- the rippled, the homogeneous, the bioturbated, and the deformed; a finely interlaminated dark gray shale and medium-fine sandstone facies; and rare thin beds of laminated dark gray shale facies. The various sandstone facies have low porosity (8-10%) and modest reservoir quality. The underlying main gas storage interval, where the sandstone has better porosity (12-15%) and less shale, consists primarily of cross-bedded, laterally discontinuous, channel facies. Thin shales occur locally and are interspersed among the reservoir sandstone strata. The sandstone is primarily cemented by silica.

Old Gamma Ray-Neutron and modern FDC-CNL logs, and core data were analyzed in order to prepare 3D models of Mount Simon V-shale and porosity. Because shale markers of the Mt. Simon could not be reliably correlated across the field or even between adjacent wells 1000’ apart, the models were constructed based on thicknesses below the top of the Mount Simon. Sandstone reservoir strata, as shown by several slice maps of the 3D distribution of porosity, include stacked channel sandstone bodies with locally continuous, bifurcating high porosity zones ½ to 1 mile wide. Adjacent to these sandstone bodies are lower porosity zones with comparable size and similar north-south orientation, which are interpreted as abandoned channel fills. Other slice maps show a more heterogeneous, less organized sandbody geometries.

 

Influence of the West Virginia Dome on Paleocurrent Patterns in the Upper Devonian-Lower Mississippian Price Formation in the Central Appalachians

 

MURPHY, SHELDON J., WV Geological Survey Morgantown, WV

KAMMER, THOMAS W., West Virginia University, Morgantown, WV

 

Upper Devonian-Lower Mississippian sedimentation was influenced by a positive area known as the West Virginia Dome located in the Central Appalachians. Paleocurrent data collected from the Price Formation demonstrates the significance of the dome on paleoflow patterns. Exposures in West Virginia are located along the Allegheny Front and include the lowermost marine Oswayo Member, Cussewago Sandstone Member, Riddlesburg Shale Member, and the uppermost non-marine Rockwell Member. These units overlie the Devonian Hampshire Formation or Greenland Gap Formation and underlie the Mississippian Greenbrier Limestone or Maccrady Formation. At the center of the dome the Price formation is absent; the Mississippian Greenbrier Limestone sits unconformably on the Devonian Hampshire Formation.

Paleocurrent data were analyzed to determine if the West Virginia Dome was being uplifted during the Late Devonian-Early Mississippian or during the Middle Mississippian. Outcrop locations were chosen around the West Virginia Dome for accurate distribution of paleocurrent data. Paleoflow indicators reveal syndepositional patterns suggesting the dome was active during the Late Devonian-Earliest Mississippian. Paleocurrents south of the dome indicate southwest to west flow patterns suggesting paleochannels meandered around the dome. Northern mapping area localities reveal west to northwest paleoflow directions.

Subsurface exploration in the Price Formation has produced large quantities of gas in West Virginia. These gas reservoirs are located in western portions of the depositional basin and include the Upper Devonian-Lower Mississippian Berea, Big Injun and Weir sandstones. The subsurface Berea is time-equivalent to the Cussewago Sandstone that outcrops in eastern West Virginia. Therefore, paleoflow patterns influenced by the West Virginia Dome may suggest trends that apply to subsurface members of Price Formation.

 

Mapping Lost or Abandoned Pipes and Utilities at Two Former Refinery Sites in Michigan

 

Mwanda, K., and Sauck, W.; Dept. of Geosciences, Western Michigan Univ.

 

The US EPA razed two former oil refinery sites in Michigan in the late 1990's. They were antiquated and both had serious, long-term spill and leakage problems. Removal of the surface equipment and tanks did not address the entire problem, as considerable below-ground piping existed at both sites. Adequate remediation of the subsurface contamination required knowledge of the locations of all the buried utilities. Initial surveying was done at both the Carson City and Kalamazoo sites using the magnetic and electromagnetic (EM) induction methods. Follow-up at specific locations was done with GPR, electrical resistivity, spontaneous potential, and induced polarization (IP).

Both sites showed numerous pipes of several types and of various lengths. Use of both the magnetic and EM methods allowed some differentiation to be made between types of pipe, for example steel pipe vs reinforced concrete drain pipes. A number of buried, reinforced foundations were also detected. At several locations, conductive vadose-zone plumes appeared to emanate from the ends of the abandoned pipelines. Considerable amounts of surficial steel fragments resulting from the demolition process had to be cleared from the sites prior to surveying. The magnetic response of most steel pipe was dominated by permanent magnetization, in which each section of pipe (between couplers) had a positive and a negative pole. A number of pipes were verified by trenching; most were found less than four feet below the surface, and their diameters ranged from 1 to 4 inches. GPR transects were limited to areas where background conductivity was below 10 mS/m, as higher conductivity zones caused severe ringing and radio signal attenuation. The maps of the pipe locations were also very useful for guiding subsequent work with other electrical methods (directed toward stratigraphy and LNAPL impacts) to areas clear of interfering, conductive pipe. At these sites where as-built drawings of subsurface installations were non-existent, high-resolution geophysics with at least two methods was very successful in revealing the locations of all buried metallic structures.

 

Paleogeography and Dundee Production in Central Michigan: Controls and Influences

 

Myles, James R., Scot Energy, Acme, MI

 

The distribution of the various types of Dundee Limestone reservoirs across central Michigan reflects the progression of depositional influences from a western lagoon, across an intervening shoal, and into an eastern open marine shelf. An isopach between the base of the Rogers City Limestone and the Detroit River Anhydrite is a useful tool for understanding the Dundee Limestone paleogeography. The dolomitized Rogers City Limestone reservoirs, characterized by efficient water-drives, are found atop the isopach "thicks" (shoal area), east of the depositional edge of the Reed City Anhydrite (lagoonal facies).

The location of the Dundee shoal to the east of the Ordovician gas-producing structures in Osceola, Newaygo, Mecosta and Montcalm Counties suggests the possibility of deeper basinal influences on Dundee paleogeography. A Precambrian continental suture trends southwest to northeast across central Michigan, bringing together basement terranes with differing styles of deformation. The Osceola to Montcalm Ordovician gas production lies north of the suture, and the productive trend is subdivided by rift-related transfer faults into half-graben arrangements of drape-fold closures overlying tilted basement blocks. Each half-graben has its distinctive dip-slope orientation. The Dundee shoal has developed over the hingelines of half-grabens whose bounding faults dip to the northeast.

The Dundee fracture porosity fields near Saginaw Bay overlie the continental suture. Subtle wrenching accompanying reactivation of basement faults by late Paleozoic compression is believed to be responsible for the development of these prolific reservoirs.

 

Unexpected Astrobleme in Hillsdale County, Michigan

 

QUILLO, ANGELA M., Miller Exploration Company, Traverse City, MI and

MURRAY, LEW P.*, Miller Exploration Company, Traverse City, MI

 

Several layers of sediments may inhibit the discovery of numerous astroblemes across the Earth. These structures are usually stumbled upon during petroleum exploration processes. Usually, as in this specific case, the structural geology differs from the geologists’ expectations leading to further study and interpretation. The study area of interest is located twelve miles south-southwest of the enormous Albion-Scipio Field in the Michigan Basin. The Albion-Scipio Field contains diagenetically altered limestone of the Trenton and Black River Formations to dolomite. This dolomite contains fractures and vugs with dispersed caverns. The Utica Shale and cap dolomite act as seals to prohibit migration of hydrocarbons from the Trenton and Black River Formations.

 

Due to the close proximity of the Albion-Scipio Field, the area of study was thought to posses similar structural geology. With this assumption, two dimensional seismic surveys and well logs were used to define the structural geology. The two-dimensional surveys overlooked important structural features, but the well logs did show extreme thickenings for certain formations. The information gathered, however, lead to further hypothesizing of the true structural geology. With such hypothesizing, a three-dimensional seismic survey revealed the true structural geology.

 

The true structure consisted of a series of faults surrounding an uplift feature within a depression. Such a structure, defined as an astrobleme, would account for the extreme formation thickenings in certain wells. However, other evidence, such as shock metamorphism, must exist before a final theory can be proved. Volcanic origin of the structure must also be ruled out for the structure to be considered an astrobleme. The existence of astroblemes is difficult to prove, but such structures will only reveal the true astrogeology of the Earth.

 

 

 

3-Dimensional Geological Visualization & Volumetrics Using RockWorks/2002

 

REED, JIM, RockWare Incorporated, Golden, Colorado

 

RockWorks/2002 is the newest version of RockWare’s integrated geological data management, analysis, and visualization tool collection. It contains a redesigned borehole data manager for manipulating well logs, geochemical, stratigraphic, production, and structural data for vertical, inclined, and deviated wellbores. Output and analytical capabilities include topographic models, well logs, cross sections, fence diagrams, and reservoir models. New interactive three-dimensional graphic capabilities (OpenGL-based) allow the user to examine reservoir volumetrics as geologic features are manipulated.

RockWorks/2002 also contains a collection of other geological utilities for basic gridding and contouring, land grids, solid modeling, 2D volumetrics, 2D and 3D feature analysis (rose and stereonet diagrams, lineation maps and densities), statistical computations and diagrams (histograms, scatterplots, ternary plots), survey mapping, coordinate conversions, and more.

The RockWorks/2002 user interface includes a self-guided teaching environment in which the user is encouraged to follow along as the program walks through a collection of case studies.

 

 

 

 

 

Regional Stratigraphic and Reservoir Investigation of the Beekmantown Dolomite and Equivalent Units (Cambrian-Ordovician) in Ohio, Pennsylvania, and New York

 

RILEY, RONALD A., representing the Beekmantown Research Consortium, and the Ohio Division of Geological Survey, Columbus, OH

 

The Beekmantown Research Consortium, partially funded by NYSERDA, conducted a regional investigation of the Beekmantown dolomite and equivalent units across eastern Ohio, western Pennsylvania, and western New York. The primary goal was to better understand the regional stratigraphy, lithology, depositional environment, and post-depositional processes controlling porosity development in the Beekmantown dolomite, and relate them to hydrocarbon production.

While Beekmantown production in the Appalachian basin has been confined to eastern Ohio, porosity development and hydrocarbon shows indicate oil and gas potential exists throughout the study area. Regional correlations from wireline logs, cores, and well cuttings indicate up to 3 distinct zones of porosity development in the Beekmantown dolomite (informally named the "A, B, and C porosity zones") that are related to multiple episodes of subaerial exposure. These porosity zones can be correlated across much of eastern Ohio and more tenuously into western Pennsylvania and New York. An FMS image from a producing Beekmantown well in Guernsey County, Ohio indicated caves up to 3 feet in diameter in the "B porosity zone." Regional core examination of the "A and B porosity zones" indicates vugs up to 4 inches across commonly filled with secondary dolomite. Many of these areas of porosity are associated with crackle, chaotic, and mosaic breccias. Local occurrences of anhydrite within the "A and B porosity zones" indicate that dissolution of evaporites, in part, controlled porosity development.

Beekmantown deposition occurred in a tidal flat to shallow marine environment along a broad continental shelf. Carbonates are dominant, and siliciclastics become more common to the northeast in Pennsylvania and New York. Locally, evaporite deposition occurred in areas of restricted circulation and elevated salinity. Multiple episodes of subaerial exposure of Beekmantown deposits created early diagenetic porosity.

 

Finding Shallow Hydrocarbons With Electrical Geophysical

Methods at a Former Refinery Site

 

Sauck, W.; Werkema, D., Dept. of Geosciences, Western Michigan Univ.; Atekwana; E., Aal, Gamal; Dept. of Geology, Univ. of Missouri, Rolla.

 

Shallow hydrocarbons (LNAPL), perched high in the unsaturated zone at a former refinery site in Kalamazoo, MI, were discovered and mapped using a dual coil electromagnetic (EM) induction system whose signal comes mainly from the 3-10 foot depth interval. The response of the LNAPL-impacted sediments in this environment was highly conductive, relative to the surrounding glacial drift. Additionally, several of the high-conductivity zones are associated with the ends of buried abandoned pipes (which are also readily mapped with the EM system). These conductive zones were investigated further with the Ground Penetrating Radar (GPR) and electrical resistivity methods. This area, at the former tank farm, consists of very heterogeneous outwash sands, gravels, and some till units. Water table was 20 to 25 feet below the surface. Multi-spacing electrical resistivity profiling was done along several transects over the anomalous conductive zones. Results showed a conductive zone centered between 3-6 foot depths. GPR was then used to profile across these conductive features. It showed that the anomalous zone was channel-form in cross-section. Additionally, attenuation of the radar signal strength by the anomalous zone corroborated the high conductivity of this zone. Finally, hand augering was done in the conductive zones, as well as in adjacent areas with normal background conductivity. Liquid hydrocarbons were encountered at 3-8 foot depths in all borings made in the anomalously conductive zones, while clean sands were found in areas of normal background conductivity. The base of the impacted zone was a thin, tight clay unit. Thus, the basal clay of the paleochannels was the impermeable unit that held the LNAPLs perched high in the vadose zone. Mapping of these shallow contaminated units has helped to understand the distribution of LNAPLs at the level of the water table.

This anomalous response, entirely contrary to what is normally expected for hydrocarbon contamination, has been seen elsewhere at old spill sites in Michigan. Hydrocarbons and sediments containing recently spilled liquid hydrocarbons normally show high resistivity. Other WMU research has shown that bacterial degradation in mature spills produces inorganic leachate and surfactants, which together allow electrically conductive paths to develop through the initially high-resistivity LNAPL-impacted layer.

 

Finding New Pays in Old Plays: New Applications for Geochemical Exploration in Mature Basins

 

SCHUMACHER, DIETMAR and HITZMAN, DANIEL C.

Geo-Microbial Technologies, Inc., Ochelata, OK

 

Detailed geochemical surveys document that hydrocarbon microseepage from petroleum accumulations is common and widespread, is predominantly vertical, and is dynamic. These characteristics create a new suite of applications for surface geochemical surveys: field development, finding by-passed pay, and monitoring hydrocarbon drainage. Because hydrocarbon microseepage is nearly vertical, the extent of an anomaly at the surface can approximate the productive limits of the reservoir at depth. The detailed pattern of microseepage over a field can also reflect reservoir heterogeneity and distinguish hydrocarbon-charged compartments from drained or uncharged compartments. Additionally, since hydrocarbon microseepage is dynamic, seepage patterns change rapidly in response to production-induced changes.

Evidence for such changes are documented with detailed microbial and soil gas surveys from Texas, Oklahoma, and Kansas. When such surveys are repeated over the life of a field or waterflood project, the changes in seepage patterns can reflect patterns of hydrocarbon drainage. Applications such as these require close sample spacing, and are most effective when results are integrated with subsurface data, especially 3-D seismic data. The need for such integration cannot be overemphasized. High-resolution microseepage surveys offer a flexible, low-risk and low-cost technology that naturally complements more traditional geologic and seismic methods. Properly integrated with seismic data, their use has led to the addition of new reserves, drilling of fewer dry or marginal wells, and optimization of the number and placement of development or secondary recovery wells.


Mississippian Cypress Sandstone Architecture in the Illinois Basin

 

SEYLER, BEVERLY and GRUBE, JOHN P., Illinois State Geological Survey, 615 East Peabody Drive, Champaign, Illinois, 61820

 

The Cypress Sandstone has been the focus of considerable research. It is the most widespread siliciclastic unit and the most prolific horizon in the Illinois Basin with production exceeding a billion barrels of oil to date. Results of reservoir characterization research sponsored by the Department of Energy through Plains Illinois, Inc. show regional sandstone trends, portions of which reveal paleotectonic influences. Detailed reservoir architecture of select oil fields shows compartmentalization plays a significant role in development and recovery programs.

The regional Cypress Sandstone architecture was established by constructing a network of cross sections in a statewide grid of more than 2000 wells. Minimum data density was four wells per township. A Cypress net sandstone thickness map shows significant sandstone depositional trends concentrated in and aligned with the present structural low of the Basin. On a regional scale, the trend of thick sandstones appears to have a strong syndepositional structural control. There is evidence that many of the current major structural features in the Illinois Basin also were active during or prior to deposition of lower Chesterian strata.

Cypress Sandstone reservoir architecture at Lawrence Field and many other fields is characterized by multiple, less than 10 foot thick, vertically stacked or shingled, sandstones that range in overall thickness from less than 10 feet to 40 feet. These sandstones form as linear ridges, oriented northeast-southwest and are commonly very compartmentalized. The linear sandstone ridges are analogous to modern-day tidal shoals. The channel- like sandstones that exceed a thickness of 100 feet, are rarely productive. Successful field development and implementation of secondary and tertiary recovery programs in these compartmentalized reservoirs requires detailed reservoir characterization.

 

 

"Train Wreck"

Energy Prices, the Energy Infrastructure and the American Consumer

 

SCHWAGER, JOHN, Belden & Blake Corporation, Canton, OH

 

In a compelling 45-minute presentation, John Schwager, President and CEO of Belden & Blake Corporation, shares how the combined forces of energy prices, the U.S. energy infrastructure and the American consumer are converging into an inevitable "Train Wreck". Through over 30 years of energy industry experience and personal research, Schwager explains where the country is today with respect to its energy environment, how we got there, and why it’s going to be difficult to meet future energy requirements. He provides an insightful analysis of the country's energy situation with a focus on electricity. His overview also includes the six energy fuels: petroleum, coal, nuclear, hydro, renewables, and natural gas.

Schwager's understanding of the U.S. energy infrastructure is evidenced by his early predictions over the past two years of the California power crisis, high oil and natural gas prices and gasoline shortages/price spikes.

This presentation will allow you to analyze the country's energy situation without having to cut through government hypocrisy and media distortion and bias. You will also be challenged to look more closely at our environmental programs and what they are costing you as an American consumer.

 

 

Stratigraphic Distribution of Rogers City Dolomitization Across the West-Central Region of the Michigan Basin

 

TAYLOR, ERIC T., Independent Geologist, Traverse City, MI

 

Historically, the upper Dundee (Rogers City formation) has been an important oil and gas zone in the west-central portion of the Michigan Basin. Approximately 100 MMBO has been recovered from the 40 commercial Rogers City fields within this region. Primary geologic controls on production include structural uplift and adequate reservoir development at the top of the Dundee.

In west-central Michigan, the Rogers City carbonate interval exhibits two distinct lithotypes; regional dense limestone laterally abutting secondary dolomite. The superior oil production is associated with the dolomite facies as porosity and permeability development is greatly enhanced. Utilizing the existing well data base, the dolomite facies can be mapped across this region as laterally extensive trends. Identification of these stratigraphic fairways provides important information for future hydrocarbon exploration. Maps exhibiting trends of Rogers City dolomitization will be displayed during the presentation.

 

Upper Cretaceous and Cenozoic Sea-Level Change Estimates Through Backstripping Analysis of Borehole Data, Onshore New Jersey

 

Van Sickel, William A., Western Michigan University,

Kalamazoo, MI; Kominz, Michelle A., Western Michigan University, Kalamazoo, MI; and Miller, Kenneth G., Rutgers University, New Brunswick, NJ

 

       Backstripping analysis of detailed stratigraphic data from the Bass River and Ancora boreholes on the New Jersey Coastal Plain (Ocean Drilling Project Leg 174AX) provides the first sea-level estimates from Upper Cretaceous borehole data and tests Cenozoic sea-level estimates from previously drilled boreholes. Results suggest a long-term (108 – 107 year) sea-level fall of approximately 100 m, mainly since the Paleocene. Superimposed 3rd order (0.5 – 3 million year) sea-level changes are less than 70 meters.  Amplitudes varied by as much as 50 meters across sequence boundaries in the Cretaceous, suggesting a maximum amplitude of 3rd order sea-level change of more than 50 meters.  Sea-level amplitudes and durations were comparable when sequences were sampled at multiple borehole sites.  This suggests that the resultant curves are an approximation of eustasy.

       An important refinement included in this study was a reassessment of the compaction of New Jersey Coastal Plain sediments through electric log analyses of onshore wells. Porosity for the dominant lithologies (sand and mud) reveal considerably lower porosity than those seen at the Cost B-2 well. With the acquisition of new (older sequences) borehole data, along with improved porosity analysis, accurate sea-level estimates are produced from the backstripping method.

 

 

 

The Impact of Thrust and Backthrust Faults in the Albanian Thrust-belt-Platform System and Opportunities

 

VELAJ, TELO K*, 1700 Street Rd., Apt. S-4, Warrington, PA 18976

XHUFI, CAUSH B, #14, 1813-25th Avenue SW, Alberta T2T1A4

 

The Albanian Thrustbelt (Supersalt complex) consist of some tectonic zones (Ionian.Kruja, Krasta zones etc.), which are westward overthrusted (500-100km.) above the autochthonous (subsalt complex). This overthrusting process is helped by the presence of the Upper Triassic sheets, which constitutes major detachment level of the alloctons.

The subsalt complex is characterized by a development of the tectonic features (thrust, overthrust, strike-slip etc.), which are developed during the collision and postcollision stage, causing:

  1. The overthrusting of the tectonic zones, masking the autochthonous structures with large dimensions and high exploration perspective.
  2. Three structural anticlinal belts (Berati, Kurveleshi, and Cika) are formed in the Ionian zone. They have overthrusted of 20-30 km. westward masking several perspective folded structures.
  3. These above structures belong duplex and triplex style.

  4. The overthrusting of their own anticlinal units of Thrustbelts (5-10 km.) which happens more in the Kurveleshi belt and less in Kruja zone. As a result of these overthrusts is formed imbrications and duplex style bringing to the masking of subthrust complex.

 

The subsalt complex (Apulia platform and South Adriatic basin) has the form of a regional monoclinal, folded in its eastern part (under the Thrustbelt) and unfolded in its western one.

Backthrust phenomenon is secondary and has taken place in both supersalt and subsalt complexes in postcollision stage. Generally they are eastward thrust (5-10 km.) faults. They have local and regional character and mask the geological structures as well.


 

Petrographic and Geochemical Study of Gypsum and Dolomite in the

Mississippian Michigan Formation, Subsurface of Western Michigan

 

VIDETICH, PATRICIA E., Department of Geology, Grand Valley State

University, Allendale, MI; and TOURRE, SARAH A., URS Corporation,

Sacramento, CA

 

The Mississippian Michigan Formation in the subsurface of western Michigan is comprised of gypsum-shale-dolomite sequences. The gypsum and dolomite were petrographically and geochemically analyzed to determine their origin. The majority of the gypsum is alabaster with a mosaic texture and some vertically oriented nodules. The gypsum is 1 to 6m in thickness and has a high gypsum to matrix ratio. The dolomite (generally ≤0.2 m thick) is unfossiliferous and non-stoichiometric. It is composed of very fine (most <10m m), subhedral to anhedral crystals. Ripples and mudcracks, formed in the underlying shale, are preserved in the dolomite as are terrestrial plant fossils.

d 34S in the gypsum ranges from +15.2 to +17.9 per mil CDT and 87Sr/86S ranges from +0.70792 to +0.70806. All these data fall within the range of estimated isotopic values for other Mississippian marine sulfates. d 18O and d 13C in the dolomite are negatively correlated and the d 18O is as heavy at +5.3 ‰ PDB and d 13C as light as -4.7 ‰.

The megascopic characteristics of the gypsum suggest subaqueous deposition, perhaps in marginal seas. The similarities between the isotopic values of the gypsum in the Michigan Formation and reported Mississippian values indicate that the gypsum precipitated from water of marine derivation with little or no influence from continental waters. Petrographic observations and isotopic data for the dolomite suggest that the precursor dolomite sediment formed in a shallow, restricted sea that was periodically freshened resulting in mixing of waters. The carbonate sediment was likely dolomitized either penecontemporaneously or soon after burial.

 

 

IET Methodology Revitalizes Resource Development in Mature Basins of Northeastern US

 

VIELLENAVE, JIM, and FONTANA, JOHN, Direct Geochemical, Golden, CO and PYRON, ARTHUR J., Pyron Consulting, Pottstown, PA

 

Recent work by the authors has revealed a need for new exploration and development techniques that can meet two criteria: 1). Ease of applicability while increasing the effective success ratio in new and known plays, and 2). Flexibility in pricing to allow adjustment to the often-rapid changes of commodity prices. Our Integrated Exploration Technology (IET) methodology involves layering of techniques that can be scaled to the budgetary or prospect requirements of individual operators.

The IET approach has been developed to address the needs of the independent operator: 1). How can I reduce my costs for exploration/development while increasing my success ratio?, 2). How can I reduce the costs for leasing or seismic confirmation studies without sacrificing the developmental potential of my prospect?, and 3). How can I maximize my return on investment and still remain cost competitive in the marketplace? Our experience using the IET methodology has shown it to be easily scaled to address the most complex or simple or exploration and developmental programs.

The IET approach involves layering of remote sensing, geochemical, non-seismic geophysical and geological methods to develop an integrated evaluation of the potential of a given prospect. We will present several examples of its application in exploration and developmental problems in the onshore basins of the Northeastern United States, including Devonian shale gas and the Trenton-Black River plays of the Appalachian Basin. These applications have successfully identified new plays, and have delineated extensional and developmental drilling opportunities.

 

 

Field and Laboratory Studies of the Anomalous Electrical Conductivity Zones Associated With LNAPL Contamination in MI

 

WERKEMA, D., and SAUCK, W; Dept. of Geosciences, W. Michigan Univ.

ATEKWANA, E.; Dept. of Geology, Univ. of Missouri - Rolla

 

High conductivity, rather than the expected low conductivity, has been measured geophysically in the LNAPL free- and residual-product zones at various contaminated sites in Michigan. The contaminants ranged from crude oil to JP-4 and gasoline. The dominant geologic material at these sites was sand, with appreciable amounts of carbonate. The effect has been seen at two former refinery sites, and at a former US Air Force Base (Wurtsmith). Water samples from the uppermost parts of the aquifer beneath these LNAPL plumes displayed electrical conductivities 3 to 5 times greater than background. Based on these results and earlier USGS hydrogeochemical studies at a pipeline spill in Bemidji, MN, we developed a working model which involved bacterial degradation of LNAPL, production of organic acids, carbonic acid, and surfactants. The acids were buffered by the calcite and dolomite grains, producing an inorganic leachate rich in Ca, Mg, and bicarbonates. Annual vertical cycling of the water table, in the presence of emulsifying surfactants, tended to break up the initially continuous LNAPL layer, allowing conductive leachate paths through the LNAPL to form.

The zones have been investigated in detail by permanent vertical arrays of electrodes -Vertical Resistivity Probes (VRP), by multi-spaced horizontal resistivity profiling at the surface, and by horizontal ground penetrating radar (GPR) profiling. The VRPs were measured repeatedly over a period of several years to better understand seasonal changes and individual infiltration events. Surface resistivity techniques could only map the shallower low-resistivity anomalies. The GPR could clearly delineate some of the leachate plumes because of the clearly attenuated GPR signal below the leachate plume.

Preliminary laboratory experiments in 18-liter reactor vessels showed rapid development (4-6 weeks) of large bacterial populations and the production of conductive leachate and surfactants. Larger semi-static column experiments have helped clarify a number of the processes and phenomena. These columns had the capability for resistivity measurements via a fixed vertical array of electrodes, as well as liquid sampling from any level with a hypodermic needle through a rubber septum along the sidewall of the column.

Michigan Basin Petroleum Development 1858–2001

 

WESTBROOK, JACK R., Michigan Oil & Gas News, Mt. Pleasant, MI

 

From the first 13-foot hand-dug commercial petroleum well in the world dug in 1858 where the Michigan Basin Dundee Formation outcrops at Oil Springs, Ontario, Canada to the latest in state-of-the-art horizontal drilling technology and research, the Michigan Geological Basin has boasted a number of firsts in it’s fifteen decade ascension to become the 17th largest crude oil producer and 11th largest natural gas producer of the 34 United States that produce petroleum.

Along with the world's first producing oil well ever dug (just into Canada in the Michigan Basin) and the world’s first gusher (ditto); Michigan was the home of the first oil well ever acidized to enhance recovery, was home state of Franklin Supply Company, a leader in onshore directional holes drilled for more than a decade and in now actively embracing horizontal drilling technology.

Beginning with the 1886 discovery of oil at St. Clair County on the Basin’s Michigan side, petroleum development in Michigan has undergone a variety of booms and busts, with this presentation summarizing Michigan’s geological and geographical petroleum production history by decade.

 

Polyphase Tectonic Movement: Southern Edge of the Rome Trough

 

WHITE, TINA M., Department of Geological Sciences, University of Kentucky, Lexington, KY; and DRAHOVZAL, JAMES A., Kentucky Geological Survey, University of Kentucky, Lexington, KY

 

The Rome Trough is a Middle Cambrian, asymmetric, rift graben that can be traced from eastern Kentucky through West Virginia and into Pennsylvania. In Kentucky the trough is bounded on the northwest by the Kentucky River Fault System, on the west by the Lexington Fault System, and on the southeast by the Rockcastle River Fault System. The Rockcastle River, Pike County, and Perry County Uplifts lie south of the Rockcastle River Fault.

The presence of these uplifts has been indicated by gravity anomalies and limited well data. An examination of single-fold, reflection-seismic data verifies the existence of the Rockcastle River Uplift and reveals a marked divergence of dip within the Cambrian reflectors on the northern side of the Rockcastle Fault. Deeper reflectors dip steeply south into the fault, whereas shallower reflectors dip to the north away from the fault. Post-Cambrian reflectors at the northern edge of the fault also show a pronounced north dip. The reflector patterns suggest Middle Cambrian extension across an originally north-dipping, listric growth fault. Later, tectonic shortening apparently rotated the fault to a south-dipping orientation and uplifted the southern block to form the Rockcastle River Uplift, dragging up the Middle Cambrian-Middle Ordovician beds on the northern block.

Determining the timing of this uplift and its relationship to the other structures along the southern edge of the Rome Trough will require further work and additional seismic data.

 

Digital Databases, Surfer Mapping and Atlas 3.0

 

WOOD, JAMES R., Michigan Tech. Univ., Houghton, MI

 

Datasets for gas and oil fields typically come in various formats. Often paper copies of driller’s reports, well logs and other reports need to be combined and cross-referenced with digital records and maps. In or case, formation top picks needed to be checked with paper copy for accuracy and new picks entered on a large scale. Traditional databases, such as MS Access, can do this task, but it is time consuming and they lack the spatial dimension, that is, they do not show the relation of the wells to each other and to other geographic markers such as section lines and roads. It is far easier and more intuitive to work with wells plotted on maps than sorting digital databases. In our work assembling large databases of formation top picks, it became apparent that we needed a better interface between the data and the operator. To fulfill that need we developed a program, ATLAS, which was designed to show well locations and attributes on in a geographic framework and have ready access to the digital database as well as all the paper documents.

The ATLAS program is now in version 3.1 and has the following capabilities. It will allow a user to pick a well or group of wells, open the database for editing as well as separate databases containing raster images of driller’s reports or scout tickets. Roads, streams, section lines, county boundaries and additional cultural information (city and town boundaries, political districts, etc.) can also be displayed. Subsets can be extracted to smaller databases which in turn can be sent to plotting routines. We have attached the data to Golden Software’s Surfer © package, for example. This not only allows us to easily locate and edit well data, but also allows us to group well and fields and sends them off to be automatically plotted. For example, we can automate the plotting of all Dundee Fields (100+) either in black and white or in color at any scale and size with whatever plotting attributes are desired. In a 750 Mhz Pentium Class computer, all 100 fields can be contoured and plotted in about 15 minutes. The output can be sent either to a plotter or to files. This capability allows easy general of atlases, quick looks at a large number of fields, and easy updating of maps as more data becomes available.

 

The program is written in Visual Basic and uses the ESRI MapObjects © control for most of the spatial display. The program is versatile and can be used in other contexts. For example, we have recently used the ATLAS program to display geochemical data from surveys as though the sample locations were wells and the values were top picks. The only change necessary was to put geochemical data in the database in place of the tables of formation top picks. ATLAS is available on the Michigan Tech Web site and disks with sample data are available.

 

Results of Recent Drilling at Vernon Field, Isabella County, MI

MI. and A Geologic Model for the Top of the Dundee Fm.

 

WOOD, J. R, BORNHORST, T. J. AND CHITTTICK, S. D.

Michigan Tech. Univ., Houghton, MI, HARRISON, W. B., BARNES, D. Western Michigan Univ., Kalamazoo; MI, QUINLAN, W. Cronus Energy LLD, and TAYLOR, E., Consultant, Traverse City, MI

 

A horizontal well with dual laterals was drilled at Vernon Field in the fall of 2000. This well was designed to probe the field for bypassed oil and was sited based on data from previous wells. The initial lateral penetrated the Dundee Formation at -2905 feet subsea and continued approximately due East for 1501 feet, mostly in hard shale (plug?) with no hydrocarbon shows. The second lateral was offset to the Northeast and about 9 feet higher in the section. This lateral encountered good shows and good reservoir rock but efforts to bring it on production failed. The well was plugged and abandoned January 5, 2001.

The main reason for the failure of the well to produce was excessive water production probably due to two main causes: (1) water introduced into the lateral via fractures, and (2) a higher water table than anticipated due to efficient previous production. If fractures were the reason, then serious doubt is cast on the use of laterals to produce bypassed oil from fields of this type. Although the use of a multi-lateral well did allow us to probe the formation for good reservoir rock, the same strategy may have doomed the effort to put the well on production by increasing the chances of cutting water–bearing faults or fractures. On the other hand, a vertical well sited over the shale plug encountered in the first lateral would have likely failed too.

A geologic model was constructed for Vernon Field that takes into account the lithologies encountered in this well. The basic model is that the first well drilled into a large shale plug which is interpreted as either a mud-filled sinkhole originally formed on the surface of karsted Dundee limestone or a shale-filled low on a similarly exposed karstic surface. It appears that the dolomitization was a hydrothermal event following karstification, either subaerially or submarine.

 

An Approach to the Accommodation Space Changes of the Fault-depression Lacustrine Basin -- From Upper Jurassic-Lower Cretaceous of Songliao Basin, North-east China

 

ZHANG, SHIQI, Department of Petroleum Resources Science, University of Petroleum, Shandong, PRC; and REN YANGANG, Daqing Oil Field, Heilongjiang, China

 

Using upper Jurassic-lower Cretaceous of Songliao basin as research target, the characteristics of the accommodation space changes of the fault-depression lake basin were studied by the ways of comprehensive explanation of seismic sections, drilling and core data. The formation styles of accommodation space were mainly controlled by the tectonic movement styles of boundary faults in the fault-depression lake basin. In the synsedimentary fault-depression accommodation space was increased mainly in vertical, and in the receding fault-depression it was produced mainly in transverse. The correlative relationship between increment of sub-aquatic accommodation space and synchronous sedimentary volume controlled the evolution of sequence and the formation of system tracts.