Geomechanical Simulation of $\hbox{CO}_2$ Injection

Abstract

Microseismic monitoring provides information about the geomechanical deformation occurring in and around the reservoir. As such, the interpretation of microseismic activity can be greatly improved by geomechanical modelling. Geomechanical models commonly use finite element techniques to simulate the deformation caused by pore pressure changes in the reservoir. Injection of $\hbox{CO}_2$ will increase the pore pressure in the reservoir. This represents the loading for the geomechanical model, which computes the deformation both inside and around the reservoir. By examining the stress evolution it is possible to identify areas in and around the reservoir where fractures are likely to form or be reactivated. In this chapter I use a relatively novel technique where a geomechanical model is coupled to a fluid-flow simulator. This allows changes in pore pressure to be passed directly to the geomechanical model, and changes in porosity and permeability to be returned to update the fluid model. The modelling method has been developed by the Integrated Petroleum Engineering, Geomechanics and Geophysics (IPEGG) consortium. In this chapter I introduce the modelling technique and demonstrate it with several simple numerical simulations. I use these to examine how factors such as the reservoir geometry and material properties affect the stress evolution during $\hbox{CO}_2$ injection.

Even the self-assured will raise their perceived self-efficacy if models teach them better ways of doing things. Albert Bandura