多层砂砾岩油藏注烟道气提高采收率技术

Enhanced oil recovery technology through flue-gas injection in multi-layer sandy conglomerate reservoirs

通过在水驱多层砂砾岩油藏中注入火驱烟道气,可实现老油田提高采收率及节能环保的双目标。并联长岩心室内驱油实验结果表明,水驱后注烟道气可有效提高油藏采收率,通过气水交替注入控制气体流度能得到更好的开发效果。在室内实验的基础上,针对A油藏开展了现场试注,进一步评估注气的可行性。根据试注动态分析及数值模拟,认为注烟道气能起到明显增油效果,但多层砂砾岩油藏连续注气方式下注入气易沿高渗、薄层窜流,导致气体早期突破。油藏规模注烟道气的注采参数优化结果表明,采取分层注烟道气、水气交替注入、水气比1∶1、交替周期7 d的效果最好。目前,A油藏投注了1个分层注气井组,取得较好的增油效果。该研究成果可以为同类油藏开发提供一定借鉴。

Enhanced oil recovery,energy saving and environmental protection can be achieved through flue-gas injection in water-flooding multi-layer sandy conglomerate reservoirs.The laboratory parallel long cores experiments show that the oil recovery can be improved through injecting flue-gas after water flooding and better results can be achieved by water-gas alternative injecting,which could control the gas mobility.On the basis of laboratory experiment,a pilot test was carried in the A reservoir to evaluate the feasibility of gas injection.It is considered that the injection of flue-gas can obtain obvious effect of oil increasing through dynamic analysis and numerical simulation,but the gas tends to early break through in thin high permeable layers through continuous gas injection in multi-layer sandy conglomerate reservoirs.The optimization of injection-production parameters through numerical simulation on reservoir scale show that the best performance can be obtained through separated layer gas injection and water-gas alternative injecting with a water/gas ratio of 1:1 and a WAG cycle of seven days.A separated layer gas injecting well group has been put into production in the A reservoir and obtains preferable effects of oil increasing.The research results can provide certain reference to develop such kinds of reservoirs.