Processes of coupling between geomechanics deformation and reservoir flow in porous media.

摘要

The basic equations for single-phase fluid flow and geomechanical deformation are briefly reviewed on a microscopic scale. The single-phase flow equations in a porous medium are then extended to multiphase flow equations, with some assumptions for transforming the flow equations from the microscopic scale to the macroscopic scale.; The coupling processes used by various authors to integrate reservoir fluid flow and reservoir deformation have been classified into four different types: implicit coupling, iterative coupling, explicit coupling and pseudo coupling. Advantages as well as disadvantages of each coupling type are briefly discussed. Among the coupling types, the iterative coupling is adopted for the purposes of studying the convergence of the link between a reservoir simulator and a geomechanics module.; A new formula for porosity as a function of pore pressure, temperature and mean total stress is developed. Furthermore, in order to improve the coupling efficiency, equivalent forms of incremental mean total stress are investigated, along with some explanations to prove why inappropriate determination of the equivalent form may lead to inaccurate results.; Several test cases are performed to show the advantages of the novel porosity formula, compared to other formulae in terms of the number of coupling iterations needed for converging and the CPU time consumed for each test case. Conclusions of the current research, as well as discussion on the future research, are given. References related to the study are listed at the end.