Multiscale Finite-volume Method For Two-phase Flow Simulations In Heterogeneous Reservoir

We present a multiscale finite-volume method(MsFVM)for single-phase flow and two-phase flow simulations in heterogeneous reservoir.Compared with conventional reservoir numerical simulation methods,MsFVM has an advantage of remaining computing accuracy in time of reducing the calculated amount due to we employ two different sets of basis functions named dual basis function and fine-scale basis function,which can capture fine scale heterogeneous features in reservoir.We start studying our MsFVM from solving single-phase flow equation.By constructing finite-volume discrete scheme,we get coarse-scale pressure.The calculated amount of this process is much less than getting fine-scale pressure in conventional reservoir numerical simulation methods.After constructing dual basis function and fine-scale basis function,finally,multiscale pressure is worked out through the linear combination of coarse-scale pressure and fine-scale basis function.A numerical experiment is provided to prove that MsFVM not only can remain computing accuracy,but also can reduce the calculated amount.In chapter four,we use MsFVM to solve two-phase flow equation,whose solving steps are similar to solving single-phase equation except the renewal of basis functions in each time step.Furthermore,the constructed massive nonlinear equations are iterative solved by adaptive time-step Newton-Raphson.In chapter five,several oilfield numerical experiments are tested and the accuracy and efficiency of MsFVM are demonstrated successfully after comparing the multiscale pressure and multiscale saturation with fine scale pressure and fine scale saturation.