At present one of effective tools of real reservoir systems simulation is the numerical solution of partial differential equations of multidimensional multiphase filtration theory with combination of well equations. Because of that the wells are a single source of information about reservoir systems, the realistic description of fluid flow around the wells is one of most challenging aspects of reservoir simulation.
In conventional reservoir simulation there is accepted that the boundary conditions for reservoirs must be to given in the production (injection) wells and in the external (internal) boundaries. Wells are assumed to be in the gridblock centers without taking into account their exact position. It leads to neglecting of closest neighbouring cells influences and the fluid flow around an off-center wells is described incorrectly. This problem is especially important in the full-field simulators development when the reservoir systems approximate with very coarse gridblocks and reservoir produces (injected) by numerous off-center wells.
In this paper the new well representation technique in the reservoir simulation is described. This technique allows to give exact off-center well position and take into account the influence from closest neighbouring gridblocks. The application of this technique is described in the explicitly and implicitly formulations.
The results of calculations by using of suggested technique was matched with results of reservoir simulation by fine-grid application and showed a good agreement. In this paper there is illustrated that the implementation of this technique allows to improve the accuracy of results and considerable decrease of computing time because of that suggested technique assumes the use of coarse grids.
