Applying Streamline Method for Viscoplastic Oil Flow Simulation

Abstract

The work is devoted to the application of the streamline method for modeling nonisothermal nonlinear flow of viscoplastic oils. Two-dimensional plane problem of flow of water, gas and viscoplastic oil. The oil phase consists of two pseudocomponents: light and heavy fractions, which can gasify. The aqueous phase is represented only by one component, which can also gasify. During the simulation, the dependence of oil rheology on temperature is taken into account. The distinctive feature of the proposed streamline method is consideration of the process of integration of the system of flow equations integrations as a set of quasiequilibrium states, which are achived by simulation on a global grid during the relaxation time. Between these states, the calculation is carried out on the streamlines. This approach allows to account for changes of pressure, temperature, saturations during solving a system, rather than using streamlines to calculate temperature and saturations at a fixed pressure. Verification of the developed program was carried out by comparison with the results of calculations on commercial software. The convergence of the method when changing the number of streamlines, grids on streamlines, as well as the relationship between the times of calculations on the global grid and streamlines was also investigated. To study the efficiency of thermal methods of enhanced oil recovery in reservoirs with viscoplastic oils, test calculations were performed on the element of a five-spot pattern. In addition, the informativeness of standard techniques for well tests interpretation for viscoplastic oils has been investigated, and recommendations have been made to determine threshold pressure gradient by well test results.