Regional Quantitative Play Fairway Analysis: Methodology, Global Examples, and Application for the East African Rift System

Transcription

1 Regional Quantitative Play Fairway Analysis: Methodology, Global Examples, and Application for the East African Rift System 1 Nicholas H. Hinz, 2 Mark Coolbaugh, 1 James E. Faulds, 2 Lisa Shevenell, and 3 Pete Stelling 1 Nevada Bureau of Mines and Geology, University of Nevada, Reno, NV, USA 2 ATLAS Geoscience, Inc., Reno, NV, USA 3 Western Washington University, Bellingham, WA, USA

2 Regional Geothermal Assessments Single Geothermal Area Regional Assement

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4 Developing the next resources Many of the easy to develop systems have already been developed around the world What should be the strategy for selecting which known systems to develop next? How do we explore for additional unknown systems? How do we find blind or hidden resources that do not have active surface features? Steady development of resources on time, on budget, with appropriately sized power plants, and sustaining power production key for maintaining investor confidence

5 Quantitative Play Fairway Analysis Play Fairway Analysis borrowed from the petroleum industry spatial analysis of reservoir, trap, seal for petroleum resources Spatial analysis of heat, permeability, fluids, cap rock for geothermal resources HEAT + PERMEABILITY + FLUIDS + CAP ROCK = PROBABILITY OF A RESOURCE

6 Full PFA Methodology Great Basin, USA INPUTS FOR HEAT Well temperatures Spring temperatures Fluid geochemistry No magmatic heat in this region 3 km depth conductive temperature gradient model Faulds et al., 2015, 2016

7 Fault Hosted Systems Regional characterization of ~425 systems in the Great Basin Region, USA 40% are blind resources Faulds and Hinz (2015)

8 Full PFA Methodology Great Basin, USA INPUTS FOR PERMEABILITY Local structural settings Earthquake epicenters Horizontal gravity gradient Recency of faulting Quaternary fault slip rate Geodetic strain rate Quaternary fault distribution Faulds et al., 2015, 2016

9 Full PFA Methodology Great Basin, USA INPUTS FOR FLUIDS Depth to Water Table Regional Aquifer Type (Carbonate or Crystalline basement) Faulds et al., 2015, 2016

10 Benchmarks Great Basin Region Statistical analysis of known power capable resources structural settings geochemistry measured temperature association with Q-fault recency/strain rate geodetic strain models EQ seismicity gravity data

11 Flow Chart for Calculating PFA Results Each input data set is weighted separately according to statistical analysis of known benchmarks, or by using expert opinion Faulds et al., 2015, 2016

12 PFA Results for the Great Basin, USA Faulds et al., 2015, 2016

13 PFA Error Calculation Faulds et al., 2015, 2016

14 PFA Degree of Existing Exploration Faulds et al., 2015, 2016

15 Infrastructure and Land Use Data Faulds et al., 2015, 2016

16 Simple Prospecting for Fault Hosted Geothermal Resources Simplified assessment Select structural target areas Ranked on Recency of faulting Fault slip rates Type of structures Known thermal data Conduct low cost exploration Hinz et al., 2015

17 Full PFA Methodology Subduction Arcs INPUTS FOR HEAT Volcanic Centers Spring Temperatures Well Temperatures Fluid/Gas Geochemistry Sinter Presense/Type/Extent of Fumaroles Shevenell et al., 2015

18 Full PFA Methodology Subduction Arcs INPUTS FOR PERMEABILITY Tectonic Setting Plate Convergence Angle Local Structural Setting Quaternary Fault Slip Rate Pleistocene vs Holocene Calderas Shevenell et al., 2015

19 Full PFA Methodology Subduction Arcs INPUTS FOR FLUIDS Fluid ph Salinity Shevenell et al., 2015

20 Benchmarks Arc Volcanic Systems Statistical analysis of 74 power capable resources tectonic strain style structural setting angle of plate convergence Quaternary fault slip rates Quaternary fault density geochemistry fumarole field size

21 Value of Benchmarks Great Basin PFA Area 34 benchmarks: Structural settings, geochemistry, measured temperature, association with Q-fault recency/strain rate, geodetic strain models, EQ seismicity, gravity data analyzed for power capable systems > 130 C Subduction Arcs 74 benchmarks: Tectonic strain style, structural setting, angle of plate convergence, geochemistry, fumarole fields, strain rate

22 PFA Results for Global Subduction Arcs Shevenell et al., 2015

23 Benchmarks and Resource Capacity Global Subduction Arcs (across many countries) 74 productive volcanic centers (7.6 GWe installed) ranges from <1 to 795 MWe averages ~103 MWe/VC median ~46 MWe/VC EARS 3 producing systems ranging from 2.4 to 659 MWe, all magmatic USA 34 producing systems ranging from <1 to >700 MWe, magmatic and fault-controlled Fault controlled systems range from <1 to 100 MWe, Average ~25 MWe

24 PFA Methodology for the EARS PUBLIC DATA SOURCES Federal surveys Databases: AGID, GRMF, Smithsonian Peer review papers, maps Conference proceedings Filter final results for Flash, Binary, Direct Use capable resources

25 Developing Benchmarks for the EARS Digital (vector) database of known thermal manifestations (individual springs and fumaroles): XY location Temperature Geochemistry Analyses relative to Seismicity geodetic strain rates local structural settings extensional versus transtensional settings magmatic versus amagmatic arc segments distribution relative to late Quaternary volcanic centers Develop a catalogue of conceptual models for end and middle member geothermal systems in the EARS

26 Summary-Conclusions Geothermal potential maps can help guide industry and governments in exploration and development Can be paired with energy infrastructure: power grids, other forms of renewables Can be updated annually as needed to guide individual nation s or industry s evolving plans and knowledge of resources/infrastructure Facilitate certain, steady incremental growth in geothermal energy, including high and low temperature resources

27 Thank You