Integrated Reservoir Simulation Studies to Optimize Recovery from a Carbonate Reservoir

摘要

A three-dimensional finite-difference reservoir simulator,integrated in an EOR expert system, has been used todetermine the reservoir management and production strategiesto optimize the oil recovery from a carbonate reservoir. Thereservoir is a candidate for an EOR process or otherwisesubject to abandonment. After screening the reservoir for anappropriate EOR process on the basis of its properties, it wasdetermined that miscible carbon-dioxide injection is the mostsuitable process. The management strategies involvedstudying different design parameters to maximize the projectprofitability. The injection techniques that were tested in thisstudy include: (1) water-alternating-gas (WAG),(2) simultaneous water-alternating-gas (SWAG) injection, and(3) gas injection in the bottom of the reservoir with waterinjection in the reservoir top. All simulation runs wereconducted using permeability fields that have beenconditioned with core data taken from wells in the field.Specific strategy that was used includes the use of horizontalinjectors in conjunction with vertical producers. This wellconfiguration has been shown to yield the best oil recoverycompared to other well configurations. Simulation resultsshow that the most economical method to produce thisreservoir was to simultaneously inject water at the reservoirtop and gas at the reservoir bottom. This production strategyhas resulted in better sweep efficiency and therefore high oilrecovery and good economics.