Petroleum Systems of the Michigan Basin—A Look at Remaining and Undiscovered Oil and Gas Resources

Based on a workshop presented by PTTC's Midwest Region - Michigan Satellite and the Michigan Oil and Gas Association on September 23, 2004 in Grand Rapids, Michigan.

BOTTOM LINE

Experts from the U. S. Geological Survey (USGS) and Universities presented useful information, normally found in "academic" circles, in a manner that independent explorationists could understand. The complex geochemistry and source of Michigan Basin hydrocarbons must be analyzed through a combination of basin modeling and thermal maturation history based on core analysis, logs, 3-D seismic data, micro-stratigraphy, and historical production data. Interpretation of basin models and thermal history can provide valuable assistance for further Michigan exploration. The Core Research Laboratory at Western Michigan University demonstrates the interest the State of Michigan and the petroleum industry has to provide valuable exploration data and tools.

PROBLEM ADDRESSED

The identification of the geological source rocks of the Michigan Basin, and how fluid migrates from source rock to reservoir presents a challenge to oil and gas operators working in the region. Historical data reveal that production cycles track technology and interpretive successes of the major basin plays. Basin complexities and the tools or approaches to unravel those complexities must be understood to produce remaining reserves and discover new reserves.

KEY WORDS:

Antrim Shale, Conodonts, Geometric Attributes, Michigan Basin Core Research Laboratory, Multi-Trace Attribute Analysis, Petroleum Systems
Stratigraphic and Thermal Modeling, Trenton-Black River

SPEAKERS:

USGS Oil and Gas Assessment of the Michigan Basin,
Christopher Swezey, U.S. Geological Survey

The History of Petroleum Production in Michigan,
Jim Duszynski, Michigan Department of Environmental Quality

Views of Existing and Prospective Producing Formations in Michigan,
A.S. (Buddy) Wylie, Michigan Technological University

Review of the Geochemistry of Michigan Basin Natural Gases, Oils and Hydrocarbon Source Rocks,
Joseph Hatch, U.S. Geological Survey

Michigan Basin Core Research Laboratory, Today and Tomorrow,
William Harrison III, Western Michigan University and Saleh al Dossary, Aramco

Conodonts Applied to Thermal Maturation and Stratigraphic Studies in the Ordovician of the Michigan Basin,
John Repetski, U.S. Geological Survey

Stratigraphic and Thermal Modeling of the Michigan Basin,
Daniel Hayba, U.S. Geological Survey

Geometric Attributes Applied to Fracture, Karst and Hydrothermal Overprints,
Charlotte Sullivan, Kurt Marfurt and C.H. (Chuck) Blumentritt, University of Houston

TECHNOLOGY OVERVIEW

The concept of applying comprehensive regional knowledge to independent exploration and hydrocarbon production is a vital way to involve the experts at specific "academic" levels in the fundamental exploration problems of independent operators. National and regional specialists presented interpretations of the petroleum systems and production cycles of the Michigan Basin and focused on how these systems apply to specific formations and the search for undiscovered oil and gas.

Introduction to Petroleum Systems: Oil Assessment

The USGS has a long history of research in the Michigan Basin, employing the petroleum systems approach. The elements of a petroleum system are the source rock, maturation, migration, reservoir rock, traps and seals. Maturation of fluids in the source rock determines what hydrocarbon products are available to migrate from the source to the reservoir rocks. Understanding the thermal history of the maturation process, migration of hydrocarbons within the basin, and structure of the rocks that form the traps and seals is the key to oil and gas production from the Michigan Basin.

Most basins have several petroleum systems. The Paleozoic sediments of the Michigan Basin are largely carbonates and evaporate beds often form the seals to preserve the oil and gas. The Ordovician Trenton Limestone and the Devonian Antrim Shale were used as examples to explain the petroleum systems concept. The Ordovician Collingwood source rocks are fractured carbonates with both structure and stratigraphic traps, hydrocarbons migrated up through hydrothermal dolomitizing fluids in faults during the Mississippian, Pennsylvanian and early Permian, and are sealed by dolomite caps. The reservoir rocks are the Trenton-Black River Limestones. The Antrim Shale forms both the source rock and the reservoir rock for an extensive gas play in the Michigan Basin. The gas is biogenic, little or no migration of hydrocarbons with maturation occurring in the deepest part of the basin. The traps and sealing mechanisms are fractures and overlying strata.

History of Petroleum Production in Michigan

Cumulative production for the Michigan Basin is 1.3 billion barrels of oil and 6,408 Bcf of gas. In 2003 oil production was 6.5 million barrels and gas production was 231 Bcf. Silurian and Ordovician formations produce both oil and gas, while production from the Devonian is primarily oil, and Mississippian production is gas. Oil production had three peaks-in the 1930s, early 1960s and in the late 1970-1980s, and has been in decline since then. Gas production remained low till the mid 1970s and has been rising since the mid 1980s with a peak in the early 1990s. Stratigraphically most of the production is from Paleozoic beds. New exploration techniques have been the spur to peaks and raises in production. Seismic methods began to be used in the Michigan Basin in the 1960s and led to the discovery of more isolated reservoirs such as pinnacle reefs. The Antrim Shale play in the northern part of the Michigan Basin peaked in 1996-1998 and has been declining since late 1998. Drilling to greater depths and increased accuracy in mapping during the past decade is bringing about an upswing in oil and gas production in the Michigan Basin.

Existing and Prospective Producing Formations

Many formations in the Michigan Basin have significant remaining oil and gas reserves. Creation of detailed structure and isopach maps for potentially productive horizons on a broad basin scale has been instrumental in identification of the formations with missed or bypassed oil. Potential source rocks for oil and gas production have been identified from the Antrim, Amherstberg, Salina, Niagara, Collingwood and Foster formations. Producing horizons identified include the Michigan Stray, Berea, Antrim, Traverse Group, Dundee, Detroit River, Richfield, Sylvania, Salina, Clinton/Burnt Bluff, Trenton/Black River, and Prairie du Chien/Glenwood. Mapping the top of the glacial drift has been important, as newer exploration techniques are finding ways to "see" under this overburden that was once impenetrable to exploration methods. The largest cumulative producing formations in the Michigan Basin are the Antrim shale at 1.8 Tcf of gas; Dundee/Reed City - 297 MMBO; Niagara - 467 MMBO; Trenton/Black River - 139 MMBO, 289 Bcf; and Prairie du Chien 584 Bcf, 14 MMBO.

Geochemistry of Natural Gases, Oils and Source Rocks

The research included a summary of all chemical data to identify genetically related families of gases and oil and source rocks in the Michigan Basin. A number of reports and databases from the 1980s and early 1990s contained relevant data. Some of this data required correction or elimination of duplicates, and additional information about producing horizons and GIS latitude and longitude data. Statistical analysis included study of gas wetness; nitrogen, carbon dioxide, hydrogen sulfide content; and carbon isotope ratios. Five major hydrocarbon intervals in the Michigan Basin were characterized: the Lower Ordovician Foster and St. Peter formations; the Middle Ordovician Trenton and Collingwood formations; the Upper Silurian Niagara and Salina groups; The Middle Devonian Amherstburg, Lucas and Dundee formations; and the Upper Devonian Antrim Shale and Mississippian Sunbury and Michigan formations.

Each interval is examined in detail with graphs of the chemical contents and isotope ratios. Nine chemically distinct producing gas horizons and five distinct oil-bearing intervals were identified from the Michigan Basin. The five stratigraphic intervals with the best source rock potential were the Foster Fm., Trenton/Collingwood Shale, Guelph Dolomite, Amherstburg Fm. and Antrim Shale

Core Research Laboratory—Today and Tomorrow

The facility at Western Michigan University has 55,000 ft of conventional core; 50,000 drillers' reports; 30,000 wireline logs; 20,000 scout tickets from 1930s-1960s; thousands of core reports, mud logs and production tests; hundreds of hand colored geologic maps, subsurface stratigraphic and field maps; and cuttings and samples from over 1,000 wells. Most of the data collected has come from company well files or materials donated by Michigan oil and gas industry companies. Most of the information has not previously been available to the public. Future plans include expansion of the storage space, and bringing back 250,000 ft of core from Michigan operators to a common, public facility for use by all.

The Core Research Laboratory's goal is to provide knowledge of oil and gas resources to the public through workshops, and to provide an excellent learning experience for students. Recent workshops have focused on low-cost, cutting edge technologies, horizontal drilling, down-hole water disposal, seismic and geochemical techniques, examination of cores and cuttings, wireline logging and geological use of the Internet. On-line data has become a rich source of information on oil and gas exploration, and the Laboratory is creating searchable databases on Michigan Basin geology.

Conodonts applied to thermal maturation and stratigraphic studies

Conodonts, the mineralized hard parts (teeth) of extinct marine animal groups, have long been used to stratigraphically identify intervals. A brief review of the structure and organization of conodont was presented, followed by more extensive analysis of their value in interpreting Michigan Basin stratigraphy. Because of their wide range from the Cambrian through the Triassic, their distribution in most marine environments, the easy to identify forms and size in cutting; conodonts are excellent biostratigraphic zone indicators. Recent studies of conodonts have shown that they are good geothermal indicators, reflected by color changes using the Conodont Color Alteration Index (CAI) developed by USGS. CAI data can be easily correlated with other thermal maturation measures, such as vitrinite reflectance, at much lower cost and is valuable in modeling basin evolution. Because the formations in the Michigan Basin are predominately carbonate, CAI data has been used to map producing horizons on a wide scale across the basin.

Stratigraphic and Thermal Modeling of the Michigan Basin

Thermal and stratigraphic modeling across the Michigan Basin was based on a transect from the southeast corner of the state through the central trough to a point offshore in the northwest corner of the lower peninsula. Well data including lithology and tops were correlated to make cross sections. Correlation of the lithologic changes across the Michigan Basin allowed for the development of a basin evolution model from PreCambrian through Recent. Vitrinite reflectance data coupled with maximum burial data was used to plot thermal maturation and the timing of thermal maturation events. The results of the 2-D model indicate that the Michigan Basin was buried approximately 4,000 ft deeper in the past than at present. Heat flow was higher along the southern margin of the basin during the time of maximum burial. Higher heat flow is related to fluid migration, while the timing of source rock maturation was related orogenic events.

Geometric Attributes Applied to Fracture, Karst and Hydrothermal Overprints

New multi-trace seismic attributes allow improved imaging. Multi-trace attributes are based on the relationship between the target trace and neighboring traces. Subtle geologic features that may be identified using seismic attributes include: fault zones, field scale joint systems and karst areas. Use of multi-trace attributes eliminates the need to pre-select horizons. Useful attributes include most Negative and Positive Curvature measures, which can be used to map faults, folds, flexures, and to predict the location of open fractures. Spectral curvature attributes allow separate examination of broad versus narrow geologic features. Examples of how multi-trace attribute analysis works were presented from seismic surveys of several Texas regions in addition to the Trenton-Black River in the Michigan Basin. The new multi-trace attributes have the potential for imaging the hydrothermal overprint of the Michigan Basin sediments.
 

CONNECTIONS:

C.H. (Chuck) Blumentritt
University of Houston
Department of Geosciences
4800 Calhoun Road
Houston, TX 77204
Phone: 713-743-3399
E-mail: cblumtritt@aol.com

Jim Duszynski
Michigan Department of Environmental Quality
P.O. Box 30256
Lansing, MI 48910
Phone: 517-241-1525
E-mail: Duszynsj@michigan.gov

William Harrison III
Western Michigan University
Geosciences Department
Kalamazoo, MI 49008-5241
Phone: 269-387-5488
E-mail: Harrison@wmich.edu

Joseph Hatch
U.S. Geological Survey
P.O. Box 25046
Denver, CO 80225
Phone: 303-236-5418
E-mail: jrhatch@usgs.gov

Daniel Hayba
U.S. Geological Survey
12201 Sunrise Drive
Reston, VA 20192
Phone: 703-648-6180
E-mail: dhayba@usgs.gov

Kurt Marfurt
University of Houston
Department of Geosciences
4800 Calhoun Road
Houston, TX 77204
Phone: 713-743-9119
E-mail: kmarfurt@uh.edu

John Repetski
U.S. Geological Survey
12201 Sunrise Valley Drive, MS 926A
Reston, VA 20192
Phone: 703-648-5486
E-mail: jrepetski@usgs.gov

Charlotte Sullivan
University of Houston
Department of Geosciences
4800 Calhoun Road
Houston, TX 77204
Phone: 713-743-3415
E-mail: esullivan@mail.uh.edu

Christopher Swezey
U.S. Geological Survey
12201 Sunrise Valley Drive, MS 956
Reston, VA 20192
Phone: 703-648-6444
E-mail: cswezey@usgs.gov

A.S. (Buddy) Wylie
Michigan Technological University
1400 Townsend Drive
Houghton, MI 49931
Phone: 906-487-1756
E-mail: aswylie@mtu.edu

For information on PTTC’s Midwest Region and its activities contact:

Steve Gustison, Illinois State Geological Survey
615 East Peabody Drive, Champaign, IL 61820
Phone 217-244-9337
Email: gustison@isgs.uiuc.edu

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