Using Fully Coupled Hydro-geomechanical Numerical Test Bed to Study Reservoir Stimulation with Low Hydraulic Pressure

This paper documents our effort to use a fully coupled hydro-geomechanical numerical test bed to study using low hydraulic pressure to stimulate geothermal reservoirs with existing fracture network. In this low pressure stimulation strategy, fluid pressure is lower than the minimum in situ compressive stress, so the fractures are not completely open but permeability improvement can be achieved through shear dilation. The potential advantage of low pressure stimulation compared with high pressure stimulation is that a large fracture network instead of a single primary fracture can be stimulated. We found that in this low pressure regime, the coupling between the fluid phase and the rock solid phase becomes very simple, and the numerical model can achieve a low computational cost. Using this modified model, we study the behavior of a single fracture and a random fracture network.