Solar-Generated Steam for Oil Recovery: Reservoir Simulation, Economic Analysis, and Life Cycle Assessment

Transcription

1 Solar-Generated Steam for Oil Recovery: Reservoir Simulation, Economic Analysis, and Life Cycle Assessment Joel Sandler, Garrett Fowler, Kris Cheng, Anthony Kovscek Department of Energy Resources Engineering Stanford University

2 Main Conclusions Continuous, variable-rate scenarios resulting from solar thermal system meet oil production benchmarks set by conventional steam flood Economic analysis points to the viability of a high solar fraction TEOR project Life cycle assessment indicates good ratio of energy output to input and correspondingly low CO 2 emissions

3 The Back-Story: ERE B.S. Required core energy resources (15-16 units) engineering fundamentals (22-29 units) technology in society (3-5 units) capstone experience (3 units) Mathematics (15-25 units) Science (26-30 units) Earth and Energy Depth (18 units student designed) fluid flow and the subsurface 3D modeling of subsurface structures Energy and earth systems

4 Creating a Capstone Experience (Big) contemporary problem Geared to student interests Use skills from across ERE curriculum Engineering solution: elements of research, analysis, and synthesis Emphasize communication skills Endicott, Alaska, 2005

5 concentrating solar power gas-fired steam generator saturated steam enhanced oil production Active Thermal Recovery Project

6 Energy 199 Participants Spring 2011 missing G. Fowler

7 Scene Setting Growing interest in solar-generated steam for TEOR Viability study using various metrics Reservoir simulation (performance) Economic analysis (value) Life-cycle assessment (impact) optimization of electricity versus EOR heat battery Targeted the San Joaquin Valley

8 Methodology: Reservoir Simulation Comparison of constant and variable rate steam floods with heat losses Model parameters and grid based on literature values for Tulare Sands (Spivak, 1987) Daily variability Effect of solar variability on injection rate modeled using variable-rate injection schedule (NREL, 2005) Intensity (W/m 2 ) 1,400 1,300 1,200 1,100 1, Seasonal variability Time (hr)

9 Methodology: Economic Analysis Six scenarios for Kern River (before tax) direct steam, cogeneration, and solar thermal systems in various ratios Linear scaling of CAPEX Assume full investment carried in 1980, SOYD depreciation, and 30- year project life Energy prices and consumption/production rates from EIA (2011)

10 Methodology: Life-Cycle Assessment 4-acre module: single transit trough including glasshouse e- Q embodied energy Materials sourced from Shenzhen, China Plant located in Bakersfield, CA Materials (including transport) and operation inputs included Per-unit LCA of materials referenced from GaBi database (2011)

11 Simulated Temperature Profile 1120 days

12 Simulated Oil Production Rate Continuous and Variable Injection Rate oil rate green: constant rate inj blue: variable rate cumulative red: constant rate inj black: variable rate

13 Sensitivity of Oil and Water Production Rate to Heat Loss oil rate (solid lines) blue: constant inj no heat losses green: constant inj heat losses red: constant inj all heat losses

14 Sensitivity of Oil Production Rate to Max Injection Pressure oil rate (solid lines) blue: constant inj, heat losses red: variable rate, heat losses green: variable rate, heat losses, increased BHP constraint

15 Results: Reservoir Simulation Cumulative recovery, breakthrough timing, and peak oil production rate are key metrics Simulation of the base and continuous injection variable-rate cases give nearly equivalent results Comparison of the variable rate and annual variability cases is further evidence that results are insensitive to short-term fluctuations in injection Using heat loss parameters from Prats (2007) and heat loss model in STARS (based on analytical solution for over and under burden heat losses in Vinsome and Westerveld, 1980) reduces the expected ultimate recovery and increases the time to steam breakthrough time but recovery remains substantial

16 Kern River Steam and Oil Production

17 Sensitivity to Discount Rate (no taxes included in NPV)

18 Results: Economic Analysis Despite high historical SOR and associated maximum steam demand, the solar thermal scenarios still yield NPVs that are comparable if not better than the traditional scenarios All solar scenarios have high CAPEX Optimal result quite sensitive to natural gas prices, electricity prices, discount rate, and method of depreciation

19 Lifecycle Energy Consumption vs. Production (Steam) 25:1 Return on Energy Invested

20 Emissions Estimates (Brandt and Unnasch, 2010; Brandt 2012)

21 Results: Life-Cycle Analysis Operations and maintenance (O&M) make up the significant fraction of energy consumption with transportation of materials proving to be negligible Glass makes up more than 57% of the total material embodied energy mix (mid case assumptions) Compared to the lifetime quantity of energy produced as steam, energy inputs from materials, operation and maintenance, and transportation largely negligible, indicating large net positive energy output from the single-transit trough system 25:1 return (steam) on energy invested

22 Discussion Limitations Geomechanical considerations Long-term glasshouse performance Non-optimized development strategy Land-use impacts Takeaways 24.4% of life-cycle emissions (or 29.5 g CO 2 /MJ RBOB) for California heavy crudes from combustion of natural gas* 20% fraction of steam from solar thermal comparable to 100% from cogeneration in terms of production emissions* *Reference values from Brandt and Unnasch 2011

23 Main Conclusions Continuous, variable-rate scenarios resulting from solar thermal system meet oil production benchmarks set by conventional steam flood Economic analysis points to the viability of a high solar fraction TEOR project Life cycle assessment indicates good ratio of energy output to input and correspondingly low CO 2 emissions

24 Acknowledgments Professors Adam Brandt and Roland Horne M. Sriyanong, M. Bazargan, E. Sagatov, R. Kabera, D. Delgado, M. Henderson GlassPoint Solar, Chevron Corp., and CMG Ltd.

25 Works Cited Brandt, Adam and Stefan Unnasch. Energy Intensity and Greenhouse Gas Emissions from Thermal Enhanced Oil Recovery. Energy Fuels NREL-National Renewable Energy Laboratory, Update: Typical Meteorological Year 3. National Solar Radiation Data Base.. Web. 23 May < solar/ old_data/ nsrdb/ / tmy3/ by_state_and_city.html#c>. O Donnell, John. Personal Communication. 5 May PE International, GaBi Life Cycle Database. < america/databases/>. Prats, Michael. Thermal Recovery Petroleum Engineering Handbook. Ed. Howard B. Bradley. Richardson, Texas: Society of Petroleum Engineers, Spivak, Allan, and J.A. Muscatello. Steamdrive Performance in a Layered Reservoir-- A Simulation Sensitivity Study. SPE Reservoir Engineering (Aug. 1987): OnePetro. Web. 22 May EIA United States Department of Energy: Energy Information Agency, Spot Prices. Web. 1 May Sigworth, H.W. Jr. ; Horman, B.W. ; Knowles, C.W. Cogeneration experience in steam EOR applications. SPE-12196; Conference: SPE annual technical conference, San Francisco, CA, USA, 5 Oct Vinsome, P. K. W. and Westerveld, J., A Simple Method for Predicting Cap and Base Rock Heat Losses in Thermal Reservoir Simulators. The Journal of Canadian Petroleum. Reservoir Performance Technology, Montreal: Canada. July-September, 1980.

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