Opening of a fault and resulting slip due to injection of fluid for the extraction of geothermal heat
The behavior of a fault with a fluid-filled region is studied for the extraction of heat from hot, dry rock masses. A fault is viewed as a prefractured plane in the earth's crust and is modeled by an interface across which two elastic bodies contact with each other, where frictional forces against the relative movement between two surfaces of the interface are taken into account. Once fluid is injected between the two surfaces, the fault will be opened up over a region where the pressure acting on the fault plane before the injection is locally smaller than that on the neighboring regions. The size of the fluid-filled region is compared with that of a crack opened by a hydraulic pressure in a homogeneous medium to show that the fluid-filled region could be used as a reservoir for the extraction of geothermal heat. The resulting slip caused by the reduction of frictional forces due to the injection of fluid is analyzed by the use of two models, i.e., an interface with frictional resistance only and an interface with both frictional resistance and fracture toughness. It is shown that the two models do not exhibit any significant difference in the size of the slipped region when the fluid-filled region is of dimensions of practical interest.
- Research Organization:
- Department of Mechanical Engineering, Tohoku University, Sendai 980, Japan
- OSTI ID:
- 5559776
- Journal Information:
- J. Geophys. Res.; (United States), Vol. 87:B2
- Country of Publication:
- United States
- Language:
- English
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