A simulation study on the effect of the dispersion on the process of enhanced oil recovery

Abstract

Gas injection is a potential proven enhanced oil recovery technique due to the difficulty of injecting water in the low permeability reservoir. In the process of gas flooding, there is mass transfer between fracture-matrix, which is called diffusion due to the fluid velocity difference in matrix and fractures. In the complex fracture network formed by hydraulic fracturing in the low permeability formation, this mass transfer is widely existed. However, it is often neglected in the past studies about optimization design of gas flooding. In this paper, embedded discrete fracture model (EDFM) using vectorization programming is built which is easy to obtain pressure gradient and velocity to characterize dispersion caused by velocity difference between matrix and fracture. And the EDFM is used to simulate the gas flooding for a typical well, which is in good agreement with Eclipse verified the accuracy of the model. Through a series of comparisons, the influences of different fracture network mode, matrix permeability, dispersion and gas injection rate on gas flooding are analyzed and the well performance is comprehensively evaluated considering the fracture network and the dispersion in the gas flooding.