Adaptive Criterion for Iterative Hydromechanical Coupling in Black-Oil Reservoir Using Pseudocompressibility

Abstract

Geomechanical analysis of oil reservoirs requires the solution of a coupled stress flow problem of highly discretized volume of rock. A proper solution to such problems might have a high computational cost, and the larger the discretization, the longer the time spent to reach the solution. This paper presents a new numerical scheme, called iterative adaptive coupling, for the solution of multiphase flow and the geomechanical coupled problems, which reduces the number of iterations for each time step and still maintains the accuracy of the solution. This numerical scheme uses a convergence criterion based on the pore fluid pressure and a pseudocompressibility as the coupling parameter. The solution of the five-spot production pattern is presented to compare this scheme with two other numerical schemes: two-way iterative coupling and sequential. The two-way coupling is used as a reference. The sequential scheme carries out only one iteration per time step with a significant reduction in time, about 50%, but presents results that are not accurate and reliable. The adaptive scheme reduces the solution time by more than 35% and keeps the solution within 0.12% of the solution obtained using the two-way scheme.