+Websites accessed December 15, 2013. Key Factors for Success in Unconventionals: Characteristics, Key Plays, Typical Challenges Need to know: Big Picture: Basin Analysis/ Geological History Depositional environment / history Burial Thermal history Maturation Structural history (natural fractures / faults / erosion) Geological factors Thickness Maturity Gas content/rock properties Areal extent Depth Structural complexity Lateral continuity Closer Look: Stratigraphy / Structure Lithology Formation attributes Structure Geomechanics Prospectivity issues Producibility What makes a reservoir or play unconventional? Susan Smith Nash Outline of Presentation and Resources / Additional References+ 1
Cander, Harris, 2013, What Are Unconventional Resources? A simple definition using viscosity and permeability. http://www.searchanddiscovery.com/documents/2012/80217cander/ndx_cander.pdf EIA, 2010, Unconventional Fossil Energy: Domestic Resource Opportunities and Technology Applications: DOE / NETL: http://www.netl.doe.gov/technologies/oil-gas/publications/epreports/unconventionalfossilenergy_reportdraft4-23-10v2.pdf Stoneburner, Richard, 2013, The Exploration, Appraisal and Development of Unconventional Reservoirs: A New Approach to Petroleum Geology: AAPG Distinguished Lecture Tour. http://www.searchanddiscovery.com/documents/2013/41115stoneburner/ndx_stoneburner.pdf EIA, 2010, Major Tight Plays, Lower 48 States. http://www.eia.gov/oil_gas/rpd/tight_gas.pdf Characteristics of unconventionals Shale plays (gas, liquids-rich) Boyer, Chuck; Bill Clark, Valerie Jochen, and Rick Lewis, 2011, Shale Gas: A Global Resource: Oilfield Review. 12p.. http://www.slb.com/~/media/files/resources/oilfield_review/ors11/aut11/03_shale_gas.ashx Zagorski, W.A., D. Bowman, J. Morris, and C. Yang, 2013, Marcellus Shale - Geologic Considerations for an Evolving North American Liquids-Rich Play: Search and Discovery Article #110166 (2013).. http://www.searchanddiscovery.com/documents/2013/110166zagorski/ndx_zagorski.pdf Shale gas Crain s Petrophysical Handbook, 2012, Shale Gas Basics. http://www.spec2000.net/17-specshgas.htm Shale oil Crain s Petrophysical Handbook, 2012, Tight Oil Basics. http://www.spec2000.net/18-tightoil.htm Jarvie, D., 2011, Unconventional Oil Petroleum Systems: Shales and Shale Hybrids: Search and Discovery Article #80131 (2011). http://www.searchanddiscovery.com/documents/2011/80131jarvie/ndx_jarvie.pdf Plays Coalbed Methane 2
North America Shale Play Roundup: Durham, L.S., 2012, Shale List Grows: AAPG Explore July, 2012. http://www.aapg.org/explorer/2012/07jul/shale_list0712.cfm Barnett First main shale gas Depth: 6500 8500 ft Thickness: 100 600 ft Average IPs: 4.0 MMcfd Laterals: 3,500 5,000 ft Sweet spots: Ro associated with depth of burial Problems: learning curve slickwater fracs; non-isolated multistage horizontals; declines / need to refract; can drill into wet lime (Ellenburger) and destroy well. Waldo, David, 2012, A Review of Three North American Shale Plays: Learnings from Shale Gas Exploration in the Americas: Search and Discovery Article #80214 (2012). http://www.searchanddiscovery.com/documents/2012/80214waldo/ndx_waldo.pdf Review of workflows useful in the Barnett Shale Volumetric attributes Basement control of faulting and collapse Velocity anisotropy analysis Azimuthal AVO analysis Improved lateral resolution through innovative migration Marfurt, Kurt., 2011, Seismic Expression of Shale Reservoirs: Opportunities for Technology Improvement: Oklahoma Geological Survey / OU School of Geology Geophysics. http://www.ogs.ou.edu/meetings/presentations/unconvres809/marfurt.pdf Marcellus Similar to Barnett monoclonal dip in a foreland setting Extreme sweet spots Geological factors (fractures, thickness, pressure, TOC, etc.) 3
Completion approaches (water frac / foam frac / N 2 frac) Pressure gradient low pressure -- must understand to successfully complete & produce TOC highly variable Commercial Consortia (Core Lab / Weatherford) Zagorski, W.A., Douglas C. Bowman, Martin Emery, and Gregory R. Wrightstone, 2011, An overview of Some Key Factors Controlling Well Productivity in Core Areas of the Appalachian Basin Marcellus Shale Play: Search and Discovery Article #110147 (2011). http://www.searchanddiscovery.com/documents/2011/110147zagorski/ndx_zagorski.pdf Bakken World class source rocks Hard, siliceous, pyritic, fissile, organic-rich TOC.s as high as 40 wt% (average 11%) High OM indicates anoxic conditions (amorphous-sapropelic OM) HC generation: 10 to 400 B bbl oil Reservoir-favorable facies and diagenetic history (matrix permeability) Mature source rocks form continuous oil column (pervasive saturation) Favorable history of fracture development: folds, faults, solution of evaporites, high fluid pressures, regional stress field (fracture permeability) Sonnenberg, Steve, 2010, The Bakken Petroleum System of the Williston Basin: AAPG Education presentation. http://education.aapg.org/bakken/bakkenwebinarslides.pdf Crain s Petrophysical Handbook, 2012, Bakken Geology. http://www.spec2000.net/18-tightoil.htm#b2 Eagle Ford Lower Cretaceous Depth: 4000 12,000 ft Thickness: 100 475 ft TOC: 3 5 % Vitrinite Reflectance: 1.0 1.27% Ro Porosity = 9-12% Permeability = nanodarcy range 4
Pressure gradient: 0.43-0.70 psi/ft Gas / liquids-rich production line: oil window Cander, Harris, 2012, Sweet Spots in Shale Gas and Liquids Plays: Prediction of Fluid Composition and Reservoir Pressure: Search and Discovery Article #40936. http://www.searchanddiscovery.com/documents/2012/40936cander/ndx_cander.pdf Peebles, Ross, 2012, Integrating Seismic, Microseismic and Engineering Data to Optimize Lateral Placement and Completion Design in the Eagle Ford: Search and Discovery Article #80251 (2012). http://www.searchanddiscovery.com/documents/2012/80251peebles/ndx_peebles.pdf Niobrara Chalk: fractures / pressure) Pervasive petroleum saturation Mature source rocks Abnormally pressured Generally lacks down-dip water Updip water saturation Low porosity and permeability reservoirs Fields have diffuse boundaries Enhanced by fracturing Folding and faulting Tectonic, diapiric, slumping Wrench faults Geologic history of fractures Recurrent movement along basement shear zones Solution of evaporites High fluid pressure Maturation of source rocks Compaction and dewatering Regional stress field 5
Deacon, Marshall, and Robert Lieber, 2013, Integrated Reservoir Evaluation as a Means for Unlocking Maximum Resource Value in an Unconventional Reservoir: Niobrara Formation, DJ Basin, Colorado: Search and Discovery Article Article #110168 (2013). http://www.searchanddiscovery.com/documents/2013/110168deacon/ndx_deacon.pdf Sonnenberg, Stephen. (2011) The Niobrara Petroleum System, A Tight Oil/Gas Resource Play: AAPG Education Presentation, 51p. http://education.aapg.org/niobrara/niobrarasystemslides.pdf Woodford Cardott, Brian J., 2013, Woodford Shale: from Hydrocarbon Source Rock to Reservoir: Search and Discovery Article #50817 (2013). http://www.searchanddiscovery.com/documents/2013/50817cardott/ndx_cardott.pdf Mississippian Lime Play Matson, Shane (2013). Mississippian Lime Play: From Outcrop to Subsurface - the Evolution of a Play: Search and Discovery Article #110170 (2013). http://link.videoplatform.limelight.com/media/?channelid=f5f86f09185c46118df7014b3afd744f&width=800&height=450&playerform=22d59 6cc0ab348e59291dc91cc18948d&deepLink=trues http://www.searchanddiscovery.com/documents/2013/110170matson/ndx_matson.pdf Haynesville High heat and pressure Deep Utica Oil window? Fractures / fracture networks Deeper More extensive productive area (for gas) Monterey Siliceous / complex and highly heterogeneous Diatomaceous in places / dolomitic in others 6
Fracable where siliceous and brittle Extremely tight / fractures? Pressure issues? Supermature / shale oil (use cyclic steam to produce?) Depths vary: from 8000 ft 20,000 ft, between 1000 3000 ft thick Big deal, or big bust? Drown, D., 2012, The Monterey Shale: Big Deal, or Big Bust?: AAPG Explorer, November, 2012. http://www.aapg.org/explorer/2012/11nov/monterey1112.cfm South America Vaca Muerta and La Luna General Issues with Unconventionals: Lithological variations Typical challenges Drilling: Staying in the zone, avoiding geohazards, not crossing faults or going into water zone, correct drilling fluids Completion: Hydraulic fracturing frac fluid, proppants; microseismic Production: pressure, induced & natural fractures & pressures, fracture networks (flow), proppant diagenesis Water sourcing Key Technologies Determining Prospectivity Geochemical methods: Total Organic Carbon (TOC): 2 5% by weight Minimum 15-20 m thick with high TOC levels Typically Type II/III Kerogen, with 3 6% porosity 400 nanodarcy permeability Thermal maturity 7
Ro >1.4 for dry gas Ro 1.1-1.4 for wet gas Ro 0.6-1.1 for oil (high risk ductile rock) Hydrocarbon Index (HI) = 1.0 Tmax 560+ o C Self-sourcing / generation /expulsion Geomechanical properties Pore throats / pore architecture Crain s Petrophysical Handbook, 2012, Total Organic Carbon: Total Organic Carbon (TOC) Basics. http://www.spec2000.net/11- vshtoc.htm Seismic WAZ seismic acquisition 3D seismic /imaging Stay in the zone: sweet spots Avoid geohazards Tie to fracture data Attributes (amplitude, velocity, and impedance) Bandwidth extension Acoustic impedance inversions CGG Veritas, Wide Azimuth: CGG Veritas. http://www.cgg.com/data//1/rec_docs/1900_waz-brochure.pdf Full-Azimuth processing; WAZ 3D De-Multiple, Azimuthal Velocity Analysis, WAZ Imaging. Correlate attributes (such as amplitude, velocity, and impedance) with available fracture data from wells. Far, Mehdi E; Leon Thomsen, and Colin M. Sayers, 2013, Seismic characterization of reservoirs with asymmetric fractures: Geophysics, v. 78, p. N1-N10. http://www.rpl.uh.edu/papers/2013/2013_mehdi_geophysics_seismic_characterization.pdf Winters, Glenn (2013). Obstacles and Pitfalls of the Everyday Interpreter: The Role of Geophysics in Resource Plays: Search and Discovery Article #41131 (2013). http://www.searchanddiscovery.com/documents/2013/41131winters/ndx_winters.pdf 8
Determining lithologic properties Brittleness <40% Vclay (XRD analysis) / direct measurement of brittle index required Fracability Breyer, John A., Helge Alsleben, Milton Enderlin, 2011, Predicting Fracability in Shale Reservoirs: Search and Discovery Article #40783 (2011). http://www.searchanddiscovery.com/documents/2011/40783enderlin/ndx_enderlin.pdf Stress regime: Need to understand stress and geomechanical framework in order to place laterals and orient fracs in hydraulic fracturing. Pore pressure: pressure gradient from 1.75 2.5 psi/m (0.55-0.75 psi/ft) need for frac fluids and proppants Pore throats / architecture Oil Shales EOG Resources, Horizontal Oil Shale Drilling: EOG Resources. http://www.scribd.com/doc/30830861/horizontal-oil-shale-drilling-eog- Resources Reprocessing existing well log data Triple combo Density logs Quirein, John; Dan Buller, Jim Wikowsky, and Jerome Truax, 2012, Integrating Core Data and Wireline Data for Formation Evaluation and Characterization of Shale Gas Reservoirs: Search and Discovery Article #41073 (2012). http://www.searchanddiscovery.com/documents/2012/41073quirein/ndx_quirein.pdf Fracture networks Natural Induced Drilling Horizontal drilling planning Geosteering Drilling fluids & concerns Sourcing water 9
Logging while drilling (LWD) Smart drilling Completions Hydraulic fracturing Zipperfracs vs simulfracs Vermylen, J., and M. Zoback, 2011, Hydraulic Fracturing, Microseismic Magnitudes, and Stress Evolution in the Barnett Shale, Texas, USA, SPE Hydraulic Fracturing Technology Conference, January 2011. Issues Sourcing water Disposing of frac fluid Frac fluid Proppants (selection, materials (ceramic or sand), proppant diagenesis) Moos, Daniel, 2012, The Importance of Stress and Fractures in Hydrofracturing and Stimulation Performance: A Geomechanics Overview: Search and Discovery Article #80255 (2012). http://www.searchanddiscovery.com/documents/2012/80255moos/ndx_moos.pdf LaFollette, Randy, 2012, Shale Reservoir Production Results: Everything Matters, But Some Things Matter More Than Others: Search and Discovery Article #80254 (2012). http://www.searchanddiscovery.com/documents/2012/80254lafollette/ndx_lafollette.pdf Multistage fracs: Considerations Isolating the stages Frac monitoring / fracture network determination Microseismic Can determine fractures, fracture networks, connectivity, and also (potentially) 3D anticlinal structures. Low-density and lowimpedance rock is highly fracture-prone. 10
Refunjol, Xavier; Kurt Marfurt, and Joel Le Calvez, 2012, Extracting Formation Properties from Hydraulically Induced Microseisms, Seismic Attributes, and Impedance Inversion: Search and Discovery Article #80252 (2012). http://www.searchanddiscovery.com/documents/2012/80252refunjol/ndx_refunjol.pdf Perez, Roderick, 2013, Integration of Surface and Subsurface Tools in The Reservoir Characterization of Unconventional Plays: Search and Discovery Article #41211 (2013). http://www.searchanddiscovery.com/documents/2013/41211perez/ndx_perez.pdf Nagel, Neal, 2013, Critical Geomechanics Concepts for Hydraulic Fracturing and Well Completions in Shales: Search and Discovery Article #41210 (2013). http://www.searchanddiscovery.com/documents/2013/41211perez/ndx_perez.pdf McLennan, John, and Dan Potocki, 2013, Hydraulic Fracturing Complexity: Interaction between Hydraulic and Natural Fractures: Search and Discovery Article #41209 (2013). http://www.searchanddiscovery.com/documents/2013/41209mclennan/ndx_mclennan.pdf Green, S., and Roberto Suarez-Rivera, 2013, The Role of Stresses versus Rock Fabric on Hydraulic Fractures, Search and Discovery Article #41208 (2013). http://www.searchanddiscovery.com/documents/2013/41208green/ndx_green.pdf Stanford University, 2013, Stanford Center on Induced Seismicity, 25p. http://www.stanford.edu/~bakerjw/scis/introductory%20overview%20mark%20zoback.pdf Core analysis: Commercial consortia: Core Lab Weatherford University consortia with core analysis focus: University of Texas (Laubach) University of Oklahoma (Geomechanics Consortium / Abousleiman) Stanford (Zoback focus on reservoir geomechanics and induced seismicity) Production Water production / disposal / processing & reusing Oil field chemicals (corrosion, scale, etc.) Staged production 11
Isolating productive zones Chemical treatment for different types of unconventionals Decline curves Downhole pumps Gas gathering & processing (including conditioning) Hanson, Gary, 2012, Shale Gas and Tight Oil Development: An Adaptive Model Resulting from Real Long-term Solutions that Incorporate Water Resources Management and the Public Trust: Search and Discovery Article #80253 (2012). http://www.searchanddiscovery.com/documents/2012/80253hanson/ndx_hanson.pdf LaFollette, Randy, 2012, Shale Reservoir Production Results: Everything Matters, But Some Things Matter More Than Others: Search and Discovery Article #80254 (2012). http://www.searchanddiscovery.com/documents/2012/80254lafollette/ndx_lafollette.pdf Moos, Daniel, 2012, The Importance of Stress and Fractures in Hydrofracturing and Stimulation Performance: A Geomechanics Overview: Search and Discovery Article #80255 (2012). http://www.searchanddiscovery.com/documents/2012/80255moos/ndx_moos.pdf Peebles, Ross, 2012, Integrating Seismic, Microseismic and Engineering Data to Optimize Lateral Placement and Completion Design in the Eagle Ford: Search and Discovery Article #80251 (2012). http://www.searchanddiscovery.com/documents/2012/80251peebles/ndx_peebles.pdf Steffen, Kurt, 2013, Porosity, Permeability and Profitability: Integrating Geology, Reservoir Engineering and Commercial Factors for Evaluation of Unconventional Resource Opportunities: Search and Discovery Article #80283 (2013). http://www.searchanddiscovery.com/documents/2013/80283steffen/ndx_steffen.pdf Other References Bai, Baojun; M. Elgmati, Hao Zhang, and Mingzhen Wei, Rock characterization of Fayetteville shale gas plays: Fuel, v. 105, March 2013, p. 645-652. Multiple techniques were used to characterize the petrophysical properties of the rock samples from the Fayetteville shale gas play, including clay mineralogy, wettability, organic matter and their maturation, submicron pore structure, and 3-D pore structure. Geological properties of Fayetteville shale gas samples were measured using multiple disciplinary techniques. " Micro-features of shale rocks were characterized using the dual beam system (FIB/SEM)." 3D pore structure of a shale rock was reconstructed using FIB/SEM slides." The properties of a shale rock, including permeability, porosity, were calculated using the reconstructed 3D model. Busch, A. and A. Amann-Hildenbrand, 2013, Predicting capillarity of mudrocks: Marine and Petroleum Geology, v. 45, p 208-223 (using data mining with existing core information / databases). 12
Cardott, B.J., 2012, Thermal maturity of Woodford Shale gas and oil plays, Oklahoma, USA: International Journal of Coal Geology, v. 03, p. 109 119. Gentzis, Thomas. (2013) A review of the thermal maturity and hydrocarbon potential of the Mancos and Lewis shales in parts of New Mexico, USA International Journal of Coal Geology, Volume 113, 1 July 2013, Pages 64 75 Hutton, W., 2013, Accelerating benefits of shale plays with bundled technology: Pipeline & Gas Journal. October 2, 2013. Josh, M.; L. Esteban, C. Delle Piane, J. Sarout, D.N. Dewhurst, and M.B. Clennell, 2012, Laboratory characterisation of shale properties: Journal of Petroleum Science and Engineering, v. 88 89, June 2012, p. 107 124. Martini, A.M., L.M. Walter, T.C.W. Ku, J.M. Budai, J.C. McIntosh, and M. J.C., Schoell, 2003, Microbial production and modification of gases in sedimentary basins: a geochemical case study from a Devonian shale gas play, Michigan Basin. AAPG Bulletin, v. 87, p. 1355-1375. Rahm, B.G., and S.J. Riha, 2012, Toward strategic management of shale gas development: Regional, collective impacts on water resources: Environmental Science & Policy, v. 17, March 2012, p. 12 23. Rahm, B.G., J.T. Bates, L.R. Bertoia, A.E. Galford, D.A. Yoxtheimer, and S.J. Riha, 2013, Wastewater management and Marcellus Shale gas development: Trends, drivers, and planning implications: Journal of Environmental Management, v.120, 15 May 2013, p. 105-113. Romero-Sarmiento, M.-F., M. Ducros, B. Carpentier, F. Lorant, M.-C. Cacas, S. Pegaz-Fiornet, S. Wolf, S. Rohais, and I. Moretti, 2013, Quantitative evaluation of TOC, organic porosity and gas retention distribution in a gas shale play using petroleum system modeling: Application to the Mississippian Barnett Shale: Marine and Petroleum Geology, v., August 2013, p. 315-330. (applies advanced modeling tools to shale reservoirs uses Barnett.) Speight, J.G., 2013, - Origin of shale gas, in J.G. Speight, ed., Shale Gas Production Processes: Gulf Professional Publishing, Boston, 2013, Chapter 1, p. 1-23. 13