Patent ID: 8271247

Claim:
A method of modeling a reservoir system comprising: constructing a reservoir model of a reservoir system, wherein the reservoir model comprises a reservoir and a plurality of wells; constructing at least one material balance group, wherein the at least one material balance group comprises a portion of at least one of the plurality of wells, a portion of the reservoir, and at least one well management algorithm to track material balance within the at least one material balance group; simulating fluid flow through the reservoir model based on the at least one material balance group by a simulator; and reporting results of the simulation; wherein simulating fluid flow through the reservoir model includes determining boundary conditions for the reservoir model based at least partially on the at least one material balance group for a plurality of time steps, and solving fluid flow equations that represent the fluid flow through the reservoir model based on the boundary conditions for the plurality of time steps, wherein determining the boundary conditions includes calculating a cumulative voidage replacement ratio that is a cumulative volume of injected fluids at reservoir conditions divided by a cumulative volume of produced fluids at reservoir conditions, and calculating a volume injection rate (Vol inj,res ) in reservoir volumetric units for one of the plurality of time steps based on the equation Vol inj,res =(VRR target *Vol prod,res,cum −Vol inj,res,cum )−/relaxation_time+VRR target *Vol prod,res,estimated for timestep where VRR target is the target voidage replacement ratio, relaxation_time is the larger of a user specified parameter and a size of the one of the plurality of time steps, Vol prod,res,cum is a cumulative volume of produced fluids at reservoir conditions, Vol inj,res,cum is a cumulative volume of injected fluids at reservoir condition, and Vol prod,res,estimated for timestep is an estimated production rate of injectable fluids for the one of the plurality of time steps.