The compositional simulation and seismic monitoring of CO2 EOR and sequestration in new gas condensate reservoir

Abstract

AbstractWhile mature oil reservoir and aquifers are good candidates for CO2 sequestration, we proposed and investigated the alternative approach which, at the very start of production, combines CO2 sequestration and CO2 EOR in gas condensate reservoir. Firstly, we conducted compositional reservoir simulation and synthetic seismic simulation in a five-spot well pattern to investigate whether seismic data can monitor of CO2 front and gas condensate bank. The simulated results and the seismic simulation results are compared with each other. Although the density contrast among reservoir gas, injected CO2 and condensate is smaller than the density contrast in the case of CO2 sequestration in aquifer, the seismic signal can capture this smaller difference and monitor the CO2 injection front and locate the condensate zone. When there is no adequate data available for reservoir characterization at early period of production, this direct measurement is very valuable for reservoir characterization and for any stimulation of condensate block. Secondly, we compare the production by natural depletion and production combined CO2 EOR and storage at the very beginning. The latter will speed up the recovery process, increase the recovery rate while simultaneously store CO2 in reservoir. The extra benefit in gas condensate reservoir is that injection of CO2 will increase the pressure and postpone and decrease liquid dropout and relieve the condensate blocking.