Modeling COSubscript2/Subscript miscible flooding for enhanced oil recovery

摘要

The injection of fuel-generated CO_(2) into oil reservoirs will lead to two benefits in both enhanced oil recovery (EOR) and the reduction in atmospheric emission of CO_(2). To get an insight into CO_(2) miscible flooding performance in oil reservoirs, a multi-compositional non-isothermal CO_(2) miscible flooding mathematical model is developed. The convection and diffusion of CO_(2)-hydrocarbon mixtures in multiphase fluids in reservoirs, mass transfer between CO_(2) and crude, and formation damages caused by asphaltene precipitation are fully considered in the model. The governing equations are discretized in space using the integral finite difference method. The Newton-Raphson iterative technique was used to solve the nonlinear equation systems of mass and energy conservation. A numerical simulator, in which regular grids and irregular grids are optional, was developed for predicting CO_(2) miscible flooding processes. Two examples of one-dimensional (1D) regular and three-dimensional (3D) rectangle and polygonal grids are designed to demonstrate the functions of the simulator. Experimental data validate the developed simulator by comparison with ID simulation results. The applications of the simulator indicate that it is feasible for predicting CO_(2) flooding in oil reservoirs for EOR.