The Shale Spectrum: Interdisciplinary understanding across oil shale, oil-bearing shale and gas shale plays

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1 The Center for Oil Shale Technology & Research & The Colorado School of Mines 31sᵗOil Shale Symposium October 17-21, 2011 at the Cecil H. & Ida Green Center, Colorado School of Mines, Golden, Colorado The Shale Spectrum: Interdisciplinary understanding across oil shale, oil-bearing shale and gas shale plays Jeremy Boak, J. Frederick Sarg, Steven Sonnenberg Center for Applied Petroleum Systems Analysis & Research Department of Geology & Geological Engineering Colorado School of Mines

2 Shale and Mudstone Plays Steady demand and new technology drive interest in turning source rock formations into reservoirs Mudstone or shale, organic richness is key Seeking hydrocarbons that have not migrated far from their sources Is there oil that is not kerogen oil? 2 2

3 Petroleum Systems Perspective Oil shale & shale oil Oil-bearing shale & shale-hosted oil Source - USGS, Petroleum Systems and Geologic Assessment of Oil and Gas in the Uinta-Piceance Province, Utah and Colorado Gas shale & Shale gas 3 3

4 Bakken Green River Comparison 0 TOC 10 (wt 20 %) Green River Bakken

5 Technical Complexity; Geologic Diversity Development of oil shale requires artificial heating of immature kerogen, at surface or in situ Development of oil-bearing shale and gas shale depends upon more traditional methods applied in much more complex ways to kerogen that ranges from incipiently mature to overmature What can oil shale development add to the conversation? Rocks containing these hydrocarbons span same range of compositions and share rock textures and features 5 5

6 Shale and Mudstone Mineralogy argillaceous mudstone argillaceous marlstone calcareous/ dolomitic mudstone Carbonate siliceous marlstone siliceous mudstone Average Shale (1975) Bakken Barnett U. Green River L. Green River Chinese Oil Shale Thailand Oil Shale Polish Gas Shale Duvernay Muskwa Besa R. Lower black shale Besa R. Upper black shale Fort Simpson Q+F=Clay Carbonate/Clastic Clay Minerals Quartz + Feldspar 6 6

7 What Can Oil Shale Add? Physical properties of rocks across range of organic richness and mineralogic variety Understanding of kinetics of oil generation Understanding of geologic environments of organic-rich sediment Variation of organic matter type Variation of mineralogy 7 7

8 Physical Properties of Shale Systems All are very tight, impermeable mudstone and siltstone Production of hydrocarbons, natural or synthetic, depends on fracturing rock to drain the products Properties measured across temperature and pressure range needed to describe mechanisms of generation, migration and trapping of oil and gas to understand fracturing behaviour for field development Understanding properties of broad class of rocks informally called shale can be complementary 8 8

9 Shale Properties Depend on Organic Richness GPa Young's Modulus Bulk Modulus Shear Modulus Oil Yield (wt %) 9 9

10 Fracture Properties Determine Producibility Chart from Core Labs 10 10

11 Pressure Gradient Map of Altamont- Bluebell Field 11 11

12 Kinetics of Oil Generation Understanding kinetics of generation requires experiments at temperatures in the range of in situ retorts These experiments are important to understanding both synthetic and natural systems Can these models constrain models for generation in natural systems? 12 12

13 Experimental Range for Pyrolysis Slow heating Oil API Oil API Decrease with Heating Rate?? 1 year ICP 5 days Oil API Gravity Green River 1 day Fischer Assay 1 hour Changes relative reaction rates Affects volatilization of fragments Wide range of rates From ICP To surface retorting (e.g. Fischer Assay) ,000 10k 100k Heating Rate ( o C/d)

14 Diversity of Oil Shale Kinetic Models BOE 125, ,000 75,000 50,000 25,000 0 Gas Light Oil Heavy Oil Scheme 1 Scheme 2 Scheme 3 Scheme 1 Scheme 2 Produced Unproduced Unreacted Residue Scheme Produced Unproduced Unreacted Residue Produced Unproduced Unreacted Residue

15 Understanding Environments of Formation Behavior depends on organic content Also on mineralogic composition and variability Properties result in turn from Sedimentary history Depositional environments under which they formed Diagenetic alteration following deposition 15 15

16 Fischer Assay Oil Gravity 16 Specific Gravity R8 A Groove Mahogany B Groove R6 L5 R5 L4 R4 Unit L3 R3 John Savage 24 Colorado 1 Corehole CR-2 Corehole CR-1 Shell 23-X2 L2 R2 L1 R1 L0 R0

17 CR-2 Mineralogy (Dean, Howell, Pitman, 1981) Top R5 Top R

18 USBM 01A Well: Salinity, Redox, Oil & Mineral Properties 18 18

19 CAPSAR Research Consortia We have developed three separate research consortia on shale systems Green River Formation oil shale Bakken shale-hosted oil play Niobrara mudstone oil play Common ground for each of these consortia include: characterization of sedimentologic and petrologic features to create an integrated geologic framework measurement of critical properties relating to seismic characterization, rock strength and fracturing behavior modeling of rock mechanical behaviour under stress Understanding shale systems generically can provide synergistic insights across plays 19 19

20 Conclusions Integrated analysis pays general benefits Even of unusual basins like the Green River Formation basins Connections between lacustrine and marine? Some oil shale basins of ambiguous origin Stratigraphic, mineralogic, chemical characterization supports engineering property determination Kinetic models have yet to capture behavior across T and time scales 20 20

21 Shale Play Terminology Oil shale & shale oil Oil-bearing shale & Shale-hosted oil Source - USGS, Petroleum Systems and Geologic Assessment of Oil and Gas in the Uinta-Piceance Province, Utah and Colorado Gas shale & Shale gas 21 21

22 Shale and Mudstone Mineralogy argillaceous mudstone argillaceous marlstone calcareous/ dolomitic mudstone Carbonate siliceous marlstone siliceous mudstone Average Shale (1975) Bakken Barnett U. Green River L. Green River Chinese Oil Shale Thailand Oil Shale Polish Gas Shale Duvernay Muskwa Besa R. Lower black shale Besa R. Upper black shale Fort Simpson Q+F=Clay Carbonate/Clastic Clay Minerals Quartz + Feldspar 22 22