Use of Coupled Geomechanics and Fluid Flow Model for Optimization of Multistage Hydraulic Fracturing and Horizontal Wells in Enhanced Geothermal System Applications

摘要

A coupled geomechanics and fluid flow model with commercial hydraulic fracturing component was used in a geothermal research study allowing the creation of complex fracture network in the presence of largely distributed natural fractures. The role of in-situ stress state, discrete fracture network, fracturing fluid and proppant properties have been investigated for an Enhanced Geothermal System (EGS) feasibility study. Modeling results indicated that when designing for EGS wells, the connectivity between the hydraulic fractures and natural fractures for sustaining the desired heat production in the EGS operations was greatly depended on the unique reservoir characteristics of geothermal formations, including lithology, in-situ stress state, pore pressure and natural fracture characteristics such as fracture orientation as well as proper fracturing fluid viscosity, proppant concentration, pump rate, and well spacing.