Numerical simulation of water flooding in natural fractured reservoirs based on control volume finite element method

A numerical method is employed to investigate the fluid flowing dynamics in fractured reservoirs in this paper. Owing to the multi-scales and strong heterogeneity, description of fracture network systems plays a significant role for a successful fractured reservoir simulation model. Comparing to previous works, this paper proposes a combination of dual continuum and discrete fracture network (DFN) model, which is used to simulate the flow in reservoirs with multi-scale fractures and proved feasible. In the first part of the paper, implicit flow equations of oil and water phase in fractured reservoirs are established to consider the nonlinearity properties. And then the control volume finite element method based on the unstructured grid system and N-R iteration are used to obtain the numerical solution. Moreover, the accuracy of this simulator is proved to be reasonable by field data; Sensitivity analysis shows that the existences of complex multi-scale fracture networks have great impacts on water flooding. Compared with the homogeneous reservoir, natural fracture (micro and large scale) networks can change the direction and velocity of the waterfront, which finally leads to the more serious water breakthrough, higher water cut and less recovery. The research and the numerical results obtained in this paper can provide theoretical guidance for efficient and scale development of natural fractured reservoirs. (C) 2016 Elsevier B.V. All rights reserved.