致密砂岩油藏减氧空气泡沫驱油效果及注采参数优化OA

To investigate the adaptability and oil displacement efficiency of oxygen-reduced air foam flooding in tight sandstone reservoirs and optimize key parameters,a comprehensive study involving 3D geological modeling and numerical simulation was conducted based on the actual reservoir conditions of Block P in Yanchang Oilfield.The results prove that oxygen-reduced air foam flooding exhibits significantly superior advantages in enhancing oil recovery compared to water flooding,continuous gas flooding,and water-alternating-gas(WAG)flooding.Furthermore,regarding the implementation method of foam flooding,the gas-liquid alternating slug injection approach outperforms simultaneous co-injection.Particularly,it can increase the 10-year recovery factor by more than 3.5 percentage points and reduce the water cut by over 8 percentage points compared to water flooding.Sensitivity analysis of key injection-production parameters reveals that the injection-production ratio presents the most significant impact on displacement efficiency,followed by the gas-liquid ratio and foam solution concentration,while the slug cycle shows relatively less effect.In field application,it is recommended to maintain the injection-production ratio no less than 1.2,gas-liquid ratio of 3∶1,foam solution concentration of 0.45%,and slug cycle of 40 days,with subsequent adjustments based on dynamic injection-production responses.The field test results show that by implementing optimal well group selection,compared to water flooding,the water cut in reduced-o xygen air foam flooding was decreased by up to 24 percentage points,while the oil production was increased up to 88.46%.These findings provide a feasible approach for effectively improving the development performance in tight sandstone reservoirs and serve as valuable references for oxygen-reduced air foam flooding in similar reservoirs.