SEQUENTIAL FULLY IMPLICIT WELL MODELING OF TRANSMISSIBILITY FOR RESERVOIR SIMULATION

A subsurface hydrocarbon reservoir with wells is simulated by sequential solution of reservoir and well equations to simulate fluid flow inside the reservoir and well production rates. Sequential solution of reservoir and well equations treats wells as specified bottom hole pressure wells. This avoids solving large matrices resulting from the simultaneous solution of the reservoir and well equations which can be computationally very expensive for large number of unknowns and require special sparse matrix solvers. Such sequential solution involves regular reservoir system solvers complemented by a small matrix for the numerical solution of the well bottom hole pressures. The solution is on a steady state volume balance relationship of the layer completion rates, formation pressures and transmissibilities to determine completion rates for the layers of the well for the full reservoir model, and determine total rate for the well from the determined completion rates for the layers of the well.