Self-Potential Response in Laboratory Scale EGS Stimulation
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Self-potential (SP) response during stimulation of a laboratory-scale enhanced/engineered geothermal system (EGS) was monitored to improve the current understanding of its role in characterization of the stimulation process. Stimulation tests were conducted on 33.0 cm cubic blocks of igneous rocks with one injection well and four nearby producers. The data show excellent correlation between the pressure drop and the SP recorded during the fracturing and circulating phases of the tests. The main direction of fluid flow (and thus the fracture) is identified by the larger coupling coefficient in the main flow direction. The results show that the SP response is mainly controlled by electrokinetic coupling and that thermoelectric coupling is negligible. After fracturing, the coupling coefficient increases even with different saturation and electrical boundary conditions. Injection fluid salinity has been shown to have a great influence on the SP response when the salinity difference between the injected fluid and the formation fluid is large. According to the laboratory results, an SP array can be used to detect and map fluid flow in an EGS both during the fracturing and production stages. However, sufficient liquid saturation and porosity are needed to obtain a strong signal.
KeywordsSelf-potential Enhanced/engineered geothermal system Hydraulic fracture Electrokinetic coupling coefficient
This project was supported by the US Department of Energy Office of Energy Efficiency and Renewable Energy under Cooperative Agreement DE-EE0006765.0000. This support does not constitute an endorsement by the US Department of Energy of the views expressed in this publication. Partial funding of the OU Reservoir Geomechanics JIP is also appreciated.
Compliance with Ethical Standards
Conflict of Interest
The authors have no conflict of interest.
- Dukhin SS, Deriaguine BV (1974) Surface and colloid science: electrokinetic phenomena: translated from the Russian by Mistetsky A, Zimmerman M. Plenum Press, New YorkGoogle Scholar
- Giulia Di Giuseppe M, Troiano A, Somma R, Carlino S, Troise C, De Natale G (2016) A Self potential study of the summit geothermal system of the Krafla volcano (Iceland). In: EGU General Assembly Conference Abstracts, Vol 18Google Scholar
- Hu LB, Ghassemi A (2018a) Lab-scale investigation of a multi well enhanced geothermal reservoir. In Proceeding 43rd Stanford Geothermal Workshop held in Stanford University, Stanford, California, USAGoogle Scholar
- Hu LB, Ghassemi A (2018b) Heat and fluid flow characterization of hydraulically induced fracture in lab-scale. In 52nd US Rock Mechanics/Geomechanics Symposium. American Rock Mechanics AssociationGoogle Scholar
- Hu LB, Ghassemi A, Pritchett J, Garg SK (2016) Laboratory scale investigation of enhanced geothermal reservoir stimulation. In 50th US Rock Mechanics/Geomechanics Symposium. American Rock Mechanics AssociationGoogle Scholar
- Hu LB, Ghassemi A, Pritchett J, Garg SK (2017a) Experimental investigation of hydraulically induced fracture properties in enhanced geothermal reservoir stimulation. In Proceeding of 42nd Stanford Geothermal Workshop held in Stanford University, Stanford, California, USAGoogle Scholar
- Hu LB, Ghassemi A, Pritchett J, Garg SK (2017b) Characterization of hydraulically induced fracture in lab-scale enhanced geothermal reservoir, In proceeding of 41st GRC Annual Meeting in Salt Lake City, Utah, USAGoogle Scholar
- Ishido T, Pritchett J (2011) Effects of diffusion potential on self-potential distribution in geothermal areas. Geotherm Resour Counc Trans 35:1687–1691Google Scholar
- Ishido T, Pritchett J, Nishi Y, Sugihara M, Kano Y, Matsushima N, Kikuchi T, Tosha T, Ariki K (2018), Self-potential monitoring at the sumikawa geothermal field, Akita, Japan, In Proceeding of 43rd Stanford Geothermal Workshop held in Stanford University, Stanford, California, USAGoogle Scholar
- Mitchell JK (1976) Fundamentals of Soil Behavior. John Wiley and Sons, New YorkGoogle Scholar
- Moore JR (2007) Application of the self -potential method in hydrogeology. University of California, BerkeleyGoogle Scholar
- Moore JR, Glaser SD (2005) Self-potential observations during hydraulic fracturing in the laboratory. In Alaska Rocks 2005, The 40th US Symposium on Rock Mechanics (USRMS). American Rock Mechanics AssociationGoogle Scholar
- Moore JR, Glaser SD (2006) The Self-potential response during hydraulic fracturing of sierra granite, In proceeding of the Thirty-First Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, CaliforniaGoogle Scholar
- Pritchett J, Ishido T (2005) Hydrofracture characterization using downhole electrical monitoring. In Proceedings of World Geothermal Congress, TurkeyGoogle Scholar
- Schön JH (2015) Physical properties of rocks: fundamentals and principles of petrophysics. Elsevier, AmsterdamGoogle Scholar
- Tester JW, Anderson BJ, Batchelor AS, Blackwell DD, DiPippo R, Drake EM, Garnish J, Livesay B, Moore MC, Nichols K, Petty S (2006) The future of geothermal energy. Impact of enhanced geothermal systems (EGS) on the United States in the 21st Century, Massachusetts Institute of Technology, Cambridge, MA, 372Google Scholar