苏北低渗透油藏CO2驱油开发模式探讨

CO₂驱是改善低渗油藏开发效果行之有效的方法之一。针对中国石化华东油气田苏北低渗透油藏三十多年的CO₂驱油矿场实践，将华东目前注气区块按油藏特点和不同注气时机总结为4种开发模式。详细阐述了每种模式的驱油机理、适合油藏类型和典型实例。其中，深层低渗透油藏同步注气开发模式适合于深层、强水敏的低渗透油藏，能较好地补充地层能量；大倾角油藏衰竭开采后注气（吞吐）开发模式适合于大倾角、薄层且分布稳定的特低渗透油藏，可大幅度提高单井产能；高含水油藏水驱转注气开发模式适合于注水开发效果差的中高含水低渗透油藏，能有效改善水驱开发效果；二次注气开发模式适合于注气开发后再次注气的低渗透油藏，通过对开发层系、注采结构、注入方式和注入剖面的综合调整抑制气窜，可再次提高采收率。该研究成果对于低渗透油藏的CO₂驱油方式选择具有借鉴价值。

Discussion on the Development Model of CO2 Flooding in Low Permeability Reservoir in North Jiangsu

CO₂ flooding is an effective method for improving the develop effect of low-permeability reservoir. Sinopec East China Oil and Gas Field has been conducting field experiments in North Jiangsu low-permeability reservoir for 30 years. According to the experience, the current gas injecting blocks are divided into 4 types based on different reservoir characteristics and injecting periods. This paper elaborates the corresponding developing mode for each type of block. Among them, synchronizing injection is suitable for low-permeability reservoirs which are deep and water-sensitive; injection after exhaustion can substantially raise the single well deliverability of high-inclination-angle low-permeability reservoirs which are thin and steadily spreaded; the water-convert-gas injection is suitable for reservoirs with medium-high water cut after water injection; the secondary gas injection development mode is suitable for the low-permeability reservoir which is injected again after gas injection development. The recovery can be increased again by controlling gas channeling through the comprehensive adjustment of development series, injection production structure, injection mode and injection profile. The researching result has a reference significance for choosing CO₂ flooding mode in low-permeability reservoirs.