Seismic imaging of fractures in geothermal reservoirs
- Massachusetts Inst. of Tech., Cambridge, MA (United States)
- Kyungpook National Univ., Taegu (Korea, Republic of)
The fracture systems that act as conduits for fluids play an important role in the extraction of geothermal energy in both liquid- and vapor-dominated fields. Hydraulic fracturing is a common engineering practice used to enhance fluid production from reservoirs with low permeability. In hot dry rock (HDR) and in vapor-dominated reservoirs that are being depleted, it is necessary to inject water to produce steam. This process generally requires hydraulic fracturing in advance to enhance the recovery. Therefore, fracture imaging and characterization are important in obtaining a better understanding of geothermal reservoirs. In this paper the authors present two new techniques for seismic characterization of fracture systems. The first technique involves the detection and characterization of existing fractures with a seismic source at the surface and a hydrophone array in a borehole, i.e., the hydrophone vertical seismic profiling (VSP). P- and S-waves impinging on an open fracture induce fluid flow from the fracture into the borehole and generate tube waves in the borehole. Orientations of fractures can be determined by using the ratios of an S-wave generated tube wave to a P-wave generated tube wave. The second technique is the high-precision location of induced earthquakes during hydrofracturing for imaging the fracture. These approaches provide the means to obtain much more detailed information about fracture systems within geothermal reservoirs.
- Sponsoring Organization:
- Massachusetts Inst. of Tech., Cambridge, MA (United States); USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-86ER13636
- OSTI ID:
- 435575
- Report Number(s):
- CONF-960805-; TRN: IM9710%%233
- Resource Relation:
- Conference: 31. intersociety energy conversion engineering conference, Washington, DC (United States), 9-14 Aug 1996; Other Information: PBD: 1996; Related Information: Is Part Of Proceedings of the 31. intersociety energy conversion engineering conference. Volume 3: Policy impacts on energy, renewable energy resources, energy systems, environmental impact; Chetty, P.R.K.; Jackson, W.D.; Dicks, E.B. [eds.]; PB: 684 p.
- Country of Publication:
- United States
- Language:
- English
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