Unlocking Mid- Paleozoic Reservoirs in the Illinois Basin

by Will Gilliam

Introduction

- Horizontal drilling and multi-stage completion techniques have allowed operators to unlock the petroleum potential of shale and other tight oil/gas formations .

- Large-scale land rush underway in southern Illinois, focused on the New Albany Shale.

- Source Rock Geochemistry and Vitrinite reflectance (Ro) data suggests the New Albany Shale is a thermally mature, organic-rich source rock across much of the Illinois Basin.

- Like the Appalachian Basin, the Illinois Basin contains many prolific Lower Mississippian Carbonate reservoirs, ideal for horizontal development.

Illinois Basin

- Intracratonic basin that includes part of Illinois, Indiana, Kentucky, and northern Tennessee.

- Lends it geometry to deep seated basement faults that began as a failed rift aulacogen. (Buschbach and Kolata, 1991).

- 100,000 square miles of Cambrian through Permian Sedimentary rocks.

Lower Mississippian Carbonates

- The Lower Mississippian represents transition from deeper to shallower water carbonate facies (Lasemi et al., 2012), in an actively subsiding basin (Kolata, 1990).

- Chesterian Age Sandstones (Tar Springs, Cypress, Aux Vases) have been the primary conventional target across the region.

- Five Lower Mississippian formations of interest exist in the Illinois Basin: St. Genevieve, St Louis, Salem, Warsaw, and Ft. Payne.

Modified from Lewan et al., 2012

St. Genevieve – St. Louis- Salem

- Salem, St. Louis, and St. Genevieve depositional environments more similar to modern tropical carbonates (Lasemi et. al, 2012).

- Reservoir lithofacies are primarily, bioclastic, oolitic, and peloidal grainstones; sucrosic dolomite.

- Carter Oil Company, Union County, KY Completed 4/17/1946 McCloskey Interval IP 1363 bbl in 17 hours.

Carter Oil Record # 24509

Union County, Kentucky

From uky.edu/kgs

Warsaw

- The Warsaw is a transitional carbonate unit, marking a transition from deeper to shallower water environments across much of the Illinois Basin.

- Jobe and Saller (1995) describe three domiant lithofacies in Central Illinois :

Bryzoan Boundstones (Mound)

Bryzoan Grainstones (Reservoir) Fossilliferous Wackestone (Seal)

Jobe and Saller, 1995

Modified from Lasemi et al., 2012

Warsaw

- Jobe and Saller (1995) describe exploration model for Bryzoan Mound Complex.

- They postulate thick non-porous bryzoan boundstone accumulations control the distribution of reservoir lithofacies.

- Reservoir facies in bryzoan intergranular porosity, best developed along mound flanks.

- Mounds can be identified by ispoaching porous vs. nonporous Warsaw and Ft. Payne lithofacies.

Jobe and Saller, 1995

Ft. Payne

- Thin-bedded, argillaceous, cherty limestone, part pyritic and organic-rich (Lasemi, et al., 2012).

- Deposited in deep-water slope to basinal type setting (Lineback, 1966).

- Biogenic components are crinoids, bryzoans, sponge spicules, and radiolarians (Lasemi, et al., 2012).

- Best reservoirs occurs between the Warsaw/Ft- Payne Contact.

Lasemi, et al., 2012

Carbonate Development

- Successful horizontal development occurring in the Appalachian Basin (St. Louis and Ft. Payne). Miller Energy Ft. Payne horizontal well 365 bopd, 730 mcfd, 0 bwpd

- In Mississippian Carbonates, horizontal well planning contingent on grainstone porosity extent.

- Plan to land above oil water contact, Drill up-dip and TD just before mound core or extent of porosity.

- Mudlogging and Geosteering is important, analyze cuttings to determine best oil shows, and use gamma from multiple offset wells to geosteer.

New Albany Shale

- The New Albany Shale is a Late Devonian Age Organic-Rich Shale.

- Source Rock for overlying oil reservoirs.

- Reaches thickness of 450’ in basin depocenter.

- Widespread oil window, and Wet gas window in basin depocenter.

- Thermogenic (Ro > 0.6) and Biogenic gas window (Ro< 0.6) (Strapoc, et al., 2010).

Hasenmueller and Comer, 2000

New Albany Well Log

- KGS Blan #1 Carbon Sequestration Well

- Detailed petrologic, geochemical, source rock, and core evaluation of the New Albany Shale.

Nuttall, 2013

New Albany Source Rock Geochemistry - Kerogen is Type II Oil Prone, (Nuttall, 2013)

- Tmax 431-440°C, low thermal maturity, low side of oil window

- S1 ~ 4.95- 10.69

- HI ~ 509-668

- TOC ~ 4.75-9.48%

Nuttall, 2013

New Albany Shale

- Thermal maturity largely controls OM porosity development in organic rich shale. (Jarvie, 2007; Loucks et al., 2010)

- Vitrinite reflectance and Tmax delimit NAS thermal maturity windows (Barrows and Cluff, 1981), .

- Biogenic Gas occurs outside of the Ro = 0.6 contour (Strapoc et al., 2010)

- Thermogenic gas occurs in more mature parts of the basin. Occurs with the early onset of oil generation window.

-

Modified after Barrows and Cluff, 1984; Crockett and Morse 2010

New Albany Shale Porosity

- Shale porosity is complex, measured on micro-nanometer scale.

- New Albany Core Blan #1 exhibits three types of porosity (Nuttall, 2013).

- Intraparticulate porosity

- Intraparticle with pyrite and dolomite

- Intraparticle porosity in organic matter

- Backscatter Image of Intraparticle micro- and nanoporosity in degraded organic particle

- Presence of organic porosity development at low end of oil window.

Nuttall, 2013

New Albany Shale Oil Production

- Endeavor Energy Resources Whitfill #5,Breckenridge County, Kentucky

- Completed interval 1852-1860’ ; Grassy Creek member

- Original IP 200 mcfd

- Re-filed 5/30/2012; most recent test volume 33 bopd and 60 mcfd, on pump

- Completed with Water Frac, 390 bbls 45,000 lbs 20/40

KGS Record #140732

New Albany Shale Oil Production

- OILGASP Hux/R&M Farms #1

Lawrence County, Illinois

- IP 10 BO, 100 mcfd

- Completed: 2698 - 2738’

Fractures - Fractures are zones of mechanical

weakness in rock (i.e. joints, faults, or styolites)

- Open-mode fractures and faults are present in the New Albany Shale.

- Western Kentucky is composed of series of complex transtensional and transpressional faults.

- Structural variations suggest multiple fracture sets.

- S 85° E

- N 60° E

- N 45° E

- N 38° E

Gale et al, 2010

Fractures

- RSPEA Unconventional Resource Project

- Drilled two parallel horizontal NAS wells Christian County, Kentucky.

- Drilled Observation well and deployed microseismic array to observe frac.

- Noticed two fracture trends

N 65° E (Primary)

N 48° E (Secondary)

Walser, 2007

Summary

- The Lower Mississippian Carbonates contain multiple reservoir targets.

- St. Genevieve through Salem reservoirs largely occur in oolitic and peloidal grainstones.

- Warsaw and Ft. Payne porosity is best developed in Bryzoan grainstone lithofacies.

- The NAS is an organic-rich source rock, in the oil window, across much of the Illinois Basin.

- Thermal maturity places this unit at the early onset of the oil generation window, organic microporosity is somewhat developed in the KGS Blan #1.

- The NAS contains a thermongenic gas window at depth, and a biogenic gas window at shallower depths.

Barrow, M. H., and Cluff, R. M., 1984, New Albany Shale Group (Devonian- Mississippian) source rocks and hydrocarbon generation in the Illinois Basin, in Deamsion, G. and Murris, R. J., eds., Petroleum geochemistry and basin evolution: AAPG Memoir 35, p. 111-138. BUSCHBACH, T.C., AND KOLATA, D.R., 1991, Regional setting of Illinois Basin, in Leighton, M.W., Kolata, D.R., Oltz, D.F., and Eidel, J.J., eds., Interior Cratonic Basins: American Association of Petroleum Geologists, Memoir 51, p. 29–55. Gale, J. F. W., Laubach, S. E., and Fidler, L. J., 2010, natural Fractures in the New Albany Shale, Illinois Basin, and their importance for shale-gas production, AAPG Eastern Section Meeting, Abstract with Programs Hasenmueller, N. R., and J. B. Comer, eds., 2000, GIS compilation of gas potential of the New Albany Shale in the Illinois Basin: Gas Research Institute, GRI-00/0068/ IBCS4, CD-ROM. Kolata, D. R., 1990, Overview of sequences, in M. W. Leighton,D. R. Kolata, D. F. Oltz, and J. J. Eidel, eds., Interior cratonic basins: AAPG Memoir 51, p. 59–73. Lewan, M. D., Henry, M. E., Higley, D. K., and Pitman, J. K., 2002, Material-balance assessment of the New Albany- Chesterian petroleum system of the Illinois Basin, AAPG Bulletin, v. 86, No. 5, p. 745-777. LINEBACK, J.A., 1966, Deep-water sediments adjacent to the Borden Siltstone (Mississippian) delta in southern Illinois: Champaign, Illinois State Geological Survey, Circular 401, 48 p. LINEBACK, J.A., AND CLUFF, R.M., 1985, Ullin–Fort Payne, A Mississippian shallow to deep water carbonate transition in a cratonic basin, in Crevello, P.D., and Harris, P.M., eds., Deep-Water Carbonates: Buildups, Turbidites, Debris Flows and Chalks: SEPM, Core Workshop no.6, p. 1–26. Loucks, R.G., Reed, R.M., Ruppel, S.C., and Hammes, U., 2012, Spectrum of pore types and networks in mudrocks and a descriptive classification for matrix-related mudrock pores: American Association of Petroleum Geologists Bulletin, v. 96, no. 6, p. 1071–1098. JOBE, H., AND SALLER, A., 1995, Oil reservoirs in grainstone aprons around bryozoan mounds, upper Harrodsburg Limestone, Mississippian, Illinois Basin: American Association of Petroleum Geologists, Bulletin, v. 79, p. 783–800. Nuttall, B., 2013, Middle and Late Devonian New Albany Shale in the kentucky Geological Surveu Marvin Blan No. 1 Well, Hancock Count, Kentucky, Report of Investigations 17, Series XII, 64p. Treworgy, J. S., 1990, Kaskaskia Sequence, Mississippian Valmeyeran and Chesterian series, in M. W. Leighton, D. R. Kolata, D. F. Oltz, and J. J. Eidel, eds., Interior cratonic basins: AAPG Memoir 51, p. 125–142. Walser, 2007, Mapping induced Fractures and modeling them in the Western Kentucky New Albany Shale, http://www.rpsea.org/projects/07122-16/.