Resource Characterization and Quantification of Natural Gas ...


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Resource Characterization and Quantification of Natural Gas ...

  1. 1. Resource Characterization and Quantification of Natural Gas-Hydrate and Associated Free-Gas Accumulations in the Prudhoe Bay – Kuparuk River Area on the North Slope of Alaska Robert B. Hunter,, (907)-564-5733 Scott A. Digert,, (907) 770-8072 BP Exploration (Alaska), Inc. P.O. Box 196612 Anchorage, Alaska 99519-6612 Mary Poulton,, (520) 621-8391 Robert Casavant,, (520) 626-3785 Charles Glass,, (520) 621-6062 University of Arizona, Dept. Mining and Geological Engineering Mines and Metallurgy Bldg. #12 1235 E. North Campus Dr., POB 210012 Tucson, AZ 85721-0012 Roy Johnson,, (520) 621-4890 University of Arizona, Dept. of Geosciences 888 N. Euclid #510, P.O. Box 3308 Tucson, Arizona 85722-3308 Shirish L. Patil,, (907) 474-5127 Godwin A. Chukwu,, (907) 474-7748 Abhijit Y. Dandekar,, (907) 474-6427 Santanu Khataniar,, (907) 474-5658 David O. Ogbe,, (907) 474-7698 Department of Petroleum Engineering, Petroleum Development Laboratory University of Alaska Fairbanks P.O. Box 755880, 425 Duckering Building Fairbanks, AK 99775-5880 Timothy S. Collett,, (303) 236-5731 U.S. Geological Survey, Denver Federal Center P. O. Box 25046, MS939 Denver, CO 80225 The objectives of this project are to characterize, quantify, and determine the commerciality of in-place and recoverable gas-hydrate and associated free-gas resources in the Prudhoe Bay Unit (PBU) – Kuparuk River Unit (KRU) – Milne Point Unit (MPU) areas on the Alaska North Slope (ANS). The project team will accomplish these goals through integrated academic, industry, and government collaborative research designed to assess the potential for safe, cost competitive, and environmentally responsible production of these possible abundant, strategic, and secure unconventional energy resources.
  2. 2. The large magnitude of potential gas hydrate reserves and the interest in future ANS gas commercialization make this an opportune time to assess the energy resource potential of ANS gas hydrates. The PBU-KRU-MPU area is the premier area in the world for a project of this type. This area combines the presence of both gas hydrate and associated free gas within high- quality reservoirs beneath existing oil and gas facility infrastructure. This infrastructure enables access to sites, support equipment, and production facilities needed for a project of this magnitude. Gas hydrate resource assessments of northern Alaska range from 6.7 to 66.8 trillion cubic meters (TCM) (236 to 2,357 trillion cubic feet (TCF)) of gas in-place (Collett, 1997). Collett (1997) calculates the mean ANS basin gas in-place resources are 16.7 TCM (590 TCF). Alaska sites where gas hydrates are inferred or identified include the Eileen trend within the PBU – KRU – MPU areas, which may contain as much as 1.24 TCM (44 TCF) of gas in-place. Only limited, systematic gas hydrate reservoir characterization studies have been accomplished. ANS gas hydrates have not been characterized by detailed reservoir analyses to determine reservoir extent, stratigraphy, structure, continuity, compartmentalization, quality, variability, and geophysical and petrophysical property distributions. This project will study these reservoir characteristics to provide practical input to reservoir and economic models. The project will also determine the technical feasibility of gas hydrate production on the ANS. Accomplishing project goals will require a multi-phased, multi-year, collaborative project with specific deliverables to determine the technical and economic feasibility of gas hydrate and associated free gas resource development. Three phases will occur over 4 years. Each phase will build on prior phases, with clear project continuation/commerciality decisions between phases. The first phase focuses on reservoir characterization using existing seismic and well data, leading to a scoping evaluation of recoverable reserves and commercial potential. This phase will also design drilling system, data acquisition, completions, and production testing technologies. Phase 2 will apply developed technologies and integrate well, core, log, and production test data from an additional well if justified by results from Phase 1. This phase will also extend the geologic and reservoir models, include detailed analyses of structural control on geothermal gradient and hydrate stability, and refine the evaluation of reserves and commerciality. Phase 3 will further verify the resource, extend the models to full field, and include additional drilling and long-term production testing if justified by Phase 2 results. This phase could lead to a future ANS gas hydrate pilot development. Significant technical, economical, environmental and safety issues require resolution before gas hydrates become a viable energy resource. The energy resource potential of gas hydrates has been studied for nearly three decades. However, the developed knowledge has not been adequately tested or applied to practical gas hydrate resource development and economic recovery in the United States. Production from gas hydrates will likely require innovations in drilling, completion, and reservoir technology. Development of this technology could require significant capital investment. The PBU – KRU – MPU region of the ANS provides the best area for timely gas hydrate and associated free gas resource delineation studies, economic evaluations, and pilot development program plans due to the coincidence of resource presence beneath existing or planned facility infrastructure.
  3. 3. BP Alaska Methane Hydrate Project – DOE – Industry • Alaska Resource & Economics Focus • Mission • Alignment • Right Place • Alaska Prize • Definitions & Historical • Onshore Resource • Alaska Perspective • Alaska Project Specifics • Commercial Viability • Objectives/Timing Courtesy USDOE Courtesy USDOE • Technical Challenges
  4. 4. BP Alaska Gas Hydrate Project Mission: Economic Resource Characterize, quantify, & determine commerciality of gas hydrate & associated free gas resources in arctic regions through integrated academic, industry, & government collaborative research to promote safe, low cost, & environmentally responsible production of abundant, strategic, & secure energy resources Courtesy USDOE Courtesy USDOE
  5. 5. Alaska Project Collaborators • BP Exploration (Alaska), Inc. – Lead, Project Coordination & Industry Liaison • USGS – Research and Historical • University of Arizona, Tucson – Geology and Geophysics • University of Alaska Fairbanks – Petroleum & Reservoir Engineering • Advisory Committee – Industry Data Courtesy USDOE Owners and Research Collaborators Courtesy USDOE
  6. 6. Alaska Gas Hydrate Resource • Premier Area & Time for Research • Resource – Infrastructure – Alignment • Quantify/Verify Resource Size and Extent • Assess Verified Resource Commerciality • Leverage DOE Support – Research • Extend Industry Capability – Collaboration • Unconventional Resource – Challenges • Approve Phase Advance if Economic Resource • Assess Resource to Reserves Challenge • Enable Informed Industry & DOE Evaluation • Future Commerciality Options • Future Development Options Courtesy USDOE Courtesy USDOE
  7. 7. Alaska Gas Hydrate Resource • Onshore – Existing Facility, Reservoir • Eileen Trend – to 44 TCF in-place • Accessible Prize Requires Characterization • Associated Free Gas Present, Undefined • Tarn Trend – to 60 TCF in-place (IP) • Less Well Defined • No Known Associated Free Gas • North Slope Basin – to 590 TCF IP • USGS Probabilistic Play Estimates Courtesy USDOE Courtesy USDOE
  9. 9. Alaska North Slope Development Infrastructure Courtesy USDOE Courtesy USDOE
  10. 10. Alaska Gas Hydrate Resource Gas Hydrate Stability Field (m) (ft) (psi) 0 0 Rock/Sediment 0 0 Methane Gas hydrate stability field 1000 300 TARN Hydrate 500 4 TREND PRESSURE (MPa) 600 2000 Base of ice-bearing EILEEN 1000 DEPTH Permafrost 900 3000 Geothermal gradient TREND 8 Free Gas 1500 1200 4000 12 2000 1500 5000 16 2500 1800 -10 0 10 20 30 TEMPERATURE (°C) Courtesy USDOE Courtesy USDOE After Collett, 1993
  11. 11. Alaska Gas Hydrates Historical Perspective • 1970’s – Industry Awareness – Oil Focus • 1980’s – Government & Industry Research • 1990’s – Huge Potential Resource: 44 TCF+ • 2000’s – Potential Conventional Gas Commercialization = Alignment • Unconventional Resource Challenges • Encourage Industry Partnership via DOE Funds • Characterize, Quantify, & Verify – Seismic Data • Economic Viability Determines Phase Progression • Apply Innovative Research – Technical Challenges • Conceptually Similar to Viscous Oil Resource • Convert Resource to Reserves? • Provide Additional Gas within Existing Courtesy USDOE Courtesy USDOE Infrastructure & Potential Exploration Areas
  12. 12. Alaska Gas Hydrates Historical Perspective Year 1960 Initial ANS Exploration, Industry Prudhoe Bay Field Discovery 1970 NW Eileen #2 Gas Hydrate Test Well Oil-Focus Research Gap 1980 USGS Research Projects USDOE Gas Hydrate Projects 1990 BP EWE Seismic USGS Resource Assessment – 590 TCF ARCO Gas/Hydrate 2000 USDOE-BP Gas Hydrate Project Possible Pilot Development 2010 Courtesy USDOE Courtesy USDOE
  13. 13. Alaska Gas Hydrate Project Year/Phase/ ~ DOE Cost ($13.2 MM) 2001 Project Proposal to DOE 2002 I Reservoir and Fluid Characterization 2.0 & In-Place Resource Calculation Studies 2003 Drilling/Production RE/PE Studies Wells of Opportunity – Data Reservoir and Economic Modeling 2004 Proceed if Commercially Viable II Drilling, Data, Production Testing & Reserves Calculation Studies 3.6 Reservoir and Economic Modeling 2005 Proceed if Commercially Viable III 7.6 2006 Courtesy USDOE Courtesy USDOE Possible Pilot Development
  14. 14. Phase I: Assess Available Data & Verify Commerciality • Assess Existing Seismic & Well Data to Characterize Gas Hydrate – Free Gas Reservoir and Fluids Resource • Verify Resource Size and Extent • Enhance Data Collection Opportunities • Evaluate Reservoir Performance Parameters: Equilibrium, Relative Perm • Design Drilling System, Completions, Data Acquisition, & Production Testing Technology • Build Reservoir and Economic Models to Determine Phase Progression • Select Candidate Areas for Phase II Courtesy USDOE Courtesy USDOE Operations and Development Scenario
  15. 15. Phase II: Apply Technology in Field Operations, Economics • Apply Drilling, Completion, Production Testing Technology Design Developed in Phase I to Field Operations • Target Data Acquisition in Specific Areas • Integrate Seismic / Well Data to Extend, Add Detail, & Model Reservoir Character • Select/Drill Well in Best Candidate Area • Provide Staff, Facilities, & Infrastructure • Acquire Rock & Production Data in Well • Calculate Phase Progression Economics Courtesy USDOE Courtesy USDOE
  16. 16. Phase III: Verify Resource, Lead to Possible Pilot Program • Apply Drilling, Completion, Production Testing Technology Design Developed in Phase I-II to Field Operations • Enhance and Apply Production Methods in Probable Long-Term Field Operations • Provide Staff, Facilities, & Infrastructure • Acquire Reservoir & Production Data • Construct Full Field Reservoir Characterization and Reservoir Model • Study Gas Hydrate Decomposition and Geotechnical Properties Courtesy USDOE Courtesy USDOE • Calculate Pilot Development Economics
  17. 17. North Alaska Fields/Formations Chronostratigraphic Diagram ~Depth Age Sequence S N Formation Field 0 0 Mackenzie TERTIARY n Camde IAN 1000 K 2000 (Gas Hydrate) OO Tree u Ugn 3000 Spruc e ak / Badami, Ugnu BR st S ide e We dston le Mu Schrader Bluff, am Colvil Wall Lar Shale Milne Pt., WSak CRETACEOUS Nan. Torok Tarn n 4000 bia HRZ lum 5000 Upper Shale Pt. Thompson 115 k Co r ua Beechy Pt. 6000 pik Break Up BEAU Ok Kuparuk Pt. McIntyre, Niakuk 7000 Lower Shale Kuparuk, Milne Pt. Failed FORT Alpine JURASSIC UPPER KINGAK Rift Nuiqsut Nechelik IA Simpson N Lower Kingak Barrow TRIASSIC 215 Shublik Sag River 8000 Eileen Prudhoe Bay PERMIAN Ivishak Kavik ELLESMERIAN Echooka Wahoo 9000 Lisburne DEVONIAN CARBONIFEROUS Lisburne Alapah Kayak 10000 Kekiktuk Endicott Hunt Kanayut 355 Fork Franklinian Courtesy USDOE Courtesy USDOE
  19. 19. ANS Gas Hydrate/Free Gas KRU 1D-8 KRU 1C-8 NW Eileen - 02 0 500 Top Methane Hydrate Stability Field 1000 D E Base C F 1500 Permafrost Base B Gas H Permafrost ydrat es in A Rese 2000 rvoir Sand Base Methane Hydrate Stability Field Free Gas Trapped 2500 Below Gas Hydrates 3000 Courtesy USDOE Courtesy USDOE After Collett, 1993
  20. 20. Conventional 3D Seismic Time 0.5 0.75 1.0 1.25 Courtesy USDOE Courtesy USDOE Base Gas Hydrate Stability Zone
  21. 21. Technical Challenges • Gas Hydrate Productivity • Endothermic Gas Dissociation • Thermodynamic Modeling/Application • Recovery Factor Calculation Critical • Seismic Imaging • No High-Resolution Data Available • Shallow Portions of Conventional Data • Acoustic Properties Unique when within Non-Permafrost Section • Well Completion • Assess Productivity Issues • Conventional vs. NonConventional • Application of Heavy Oil Technology? Courtesy USDOE Courtesy USDOE
  22. 22. Productivity Challenges Gas Hydrate Product Methods ion Depressur t on Therma In t iza i l jec ion Inh i or In t ib t jec ion Hot Methanol Gas Gas Brine or Gas Out Out Gas Out Imperm. Rock Imperm. Rock Imperm. Rock Gas Hydrate Gas Gas Dissoc ted ia Hydrate Hydrate Hydrate Dissoc ted Hydrate ia Dissoc ted Hydrate ia Free-Gas Rese i rvo r Impermeable Rock Impermeable Rock After Collett, 2000 Courtesy USDOE Courtesy USDOE
  23. 23. BP Alaska Gas Hydrate Project Summary • PBU/KRU/MPU: Premier Area & Time • Resource – Infrastructure – Alignment • Characterize and Quantify Resource • Verify In-Place Resource & Resolve Extent • Assess Commercial Potential • Productivity/Recovery Factor - Reserves • Benefit Industry & USDOE • Potential Huge/Unconv. Gas Resource • Assess Technical/Economic Hurdles • Prize – Convert Resource to Reserves • Utilize Gas – Reservoir Energy/Sales • Enable Industry & DOE to Assess Future Courtesy USDOE Courtesy USDOE Development Potential in Accessible Area
  24. 24. Interagency Gas Hydrate R & D Objectives Attainable in Alaska • Short-Term: 4-5/7 Determine Physical/Chemical Properties Input Research to Databases and Website Improve Distribution/Volume Assessment Improve Geophysical Characterization Tools Provide Samples and Use Sampling Tools • Mid-Term: 3/3 Refine Characterization Tools Estimate Recovery Potential Develop/Test Production Methods • Long-Term: 3/4 Commercially Produce for Secure Gas Supply Provide Knowledge/Tools Supporting R & D Courtesy USDOE Courtesy USDOE Establish U.S. as Leader - Gas Hydrate R & D