特低渗透油藏注CO_2驱参数优化研究

Research on CO_2 Flooding Parameters Optimization of Extra-low Permeability Reservoirs

安塞王窑区长6储层属于特低渗透油藏,经过多年的注水开发,目前已进入中高含水期,注水开发的矛盾日益突出,进一步提高水驱采收率难度大。CO2驱在一定程度上能够弥补水驱的不足,是特低渗透油藏提高采收率的一种重要方式。以安塞王窑区长6特低渗透油藏为研究对象,分析了该区块的地质特征和注水开发中存在的问题,应用地质建模技术和油藏数值模拟技术优选了适合该试验区的CO2驱开发方式,并且进一步优化了地层压力、采油速度、水气交替时间、关井气油比和总注气量等参数。此次研究成果将为CO2混相驱现场试验流程建设、试验的实施提供基础参数,对安塞油田全面实施CO2驱油技术具有参考和借鉴作用。

The Chang-6 formation of Block Wangyao in Ansai Oilfield belongs to the extra-low permeability reservoir. Cur-rently,it has entered the high water-cut stage. It is difficult to further enhance recovery by water flooding. However,CO2 flooding is an important EOR approach in extra-low permeability reservoir,which can compensate for the disadvantages of wa-ter flooding. Taking the Chang-6 of Wangyao extra-low permeability reservoir for example,this paper analyzes the geological features of the block and the problems in water flooding development,and optimizes the CO2 flooding pattern fitting for the pilot area by applying geological modeling and reservoir numerical simulation techniques,and further optimizes the parame-ters of formation pressure,production rate,water alternating gas time,shut-in gas-oil ratio and total gas injection volume. The results of this study will offer basic parameters of CO2 miscible flooding to the construction and implementation of field test. It also provides reference to implement action of CO2 flooding technology to the entire Ansai Oilfield.