苏北复杂断块油藏二氧化碳驱油效果影响因素分析及认识

苏北盆地复杂断块油藏CO₂驱油效果差异较大，为制定提高CO₂驱油效果的有效措施，分析了其主要影响因素。对苏北9个CO₂驱区块的相关数据进行了统计，分析了井型、压裂情况、注气前油井产油量、注采比和注气方式等对CO₂驱油效果的影响。分析结果为:直井的开发效果好于水平井，非压裂井的效果好于压裂井，油井初产量越高则CO₂驱油效果越好，最佳注采比为2.5左右，而注CO₂方式对开发效果影响不大。研究结果表明，低渗透油藏采用的井型、油井是否压裂、注气前油井产油量是影响CO₂驱油效果的主要因素，在研究制定提高苏北盆地复杂断块油藏CO₂驱油效果的技术措施时，应充分考虑这些主要影响因素。 

Analyzing and Understanding the Influencing Factors of CO_2 Flooding in the Subei Complex Fault Block Reservoirs

The performance of CO₂ flooding in the complex fault block reservoirs of the Subei Basin varies greatly. In order to find effective measures to improve the development of these unique fault-block reservoirs, the main influencing factors were analyzed. Based on the data from 9 CO₂ flooding blocks in north Jiangsu, the influences of well type, fracturing conditions, initial production before gas injection, the injection-production ratio and the gas injection method on CO₂ flooding effects were analyzed. The analysis results show that the development effect of vertical wells is better than that of horizontal wells, and it is better for non-fractured wells than fractured. The higher the initial production of the well, the better the CO₂ flooding effect. The optimal injection-production ratio is around 2.5, while CO₂ injection methods play an insignificant role in the development effect. The results show that those factors, such as low permeability reservoir well type and the necessity of reservoir stimulation, are the main factors influencing CO₂ flooding. Those issues need to be fully considered in improving the CO₂ flooding effect in the complex fault block reservoirs in the Subei Basin.