The Importance of Reservoir Geomechanics in Thermal EOR

The primary oil recovery in heavy oil reservoirs is low due to the high viscosity of the oil. Thermal EOR processes attempt to recover oil beyond the primary production methods. In this regard, the geomechanical response of an oil sands/heavy oil reservoir is complex, reaching both near- and far-field temperatures and pore pressures. In this paper, the latest achievement of thermal geomechanics is investigated. It can be perceived that owning to thermal and pore pressure changes in response to vapor injection methods, isotropic unloading, and shear dilation occur with varying degrees in different geomechanical zones. The extent of these regions is based on drainage conditions within that zone that directly impact the pore pressure evolution. The reservoir has been subdivided into three zones; drained, partially drained, and undrained. Geomechanical processes can lead to significant changes in relative and effective permeability, porosity, compressibility, and reservoir stress/strain behaviors.

Keywords:

Steam injection , EOR , geomechanical characteristics