부산대학교 도서관

CO2 flooding has been widely applied in lots of low permeability reservoirs. After extensive CO2 injection,some reservoirs began to show serious gas channeling problems. CO2 foam had been successfully used tosolve gas channeling problems due to its advantages of water selective plugging features (not pluggingoil). In this paper, a novel CO2 foam system was developed for high temperature and high salinity(HTHS)(85 ℃, 60,000 mg/L) aiming at solving the gas channeling in Changqing Oilfield. Taking the foam half-lifeas the evaluation standard, the optimum foam system (0.5 wt% EC-1 + 1 wt% SiO2) for the target reservoirwas determined. The influences of temperature, salinity and pressure on the CO2 foam performance werestudied by high temperature and high pressure(HTHP)method. The ability and mechanism of anti-gaschanneling were studied by experiments of sand packed tube and microscopic displacement,respectively. The results showed that the foam system possessed good foam properties at HTHS withpressure. As the concentration of SiO2 nanoparticles increased, the resistance factor of the foam systemincreased. However, temperature showed an adverse effect on foam stability, the resistance factordecreased with the increase of temperature. The Jamin superposition and emulsion plugging mechanismof foam system was revealed by microscopic displacement experiments.