The most important consideration for geothermal energy development in non-hydrothermal scenarios is the use of hydraulic fracturing technology to establish an effective network pathway to conduct fluid from injector(s) to producer(s). The number of interconnected fractures and their deformation of the network pathway becomes an important parameter to characterize effective conductivity in geothermal reservoirs. A coupled hydro-mechanical model is used to study conductivity aperture changes by taking account the effect of fracture deformation. The deformation characteristics described invoke a pre-peak linear elastic constitutive relationship and non-linear elastic-plastic constitutive behavior after the peak stress is reached. Starting with accepted dynamic friction-weakening, a hydraulic aperture concept is superimposed and modifications are suggested to available post-peak elastic-plastic constitutive models. Displacement discontinuity method (DDM) is used to construct a boundary element method, which is able to analyze the induced stress field around the unconnected natural fracture. As a result, the unconnected fracture will be in a new stress zone which includes in-situ stress and induced stress. The Barton criterion is used to judge the stability of the disconnected fractures under the new stress field.

This content is only available via PDF.
You can access this article if you purchase or spend a download.