低渗油藏CO_2-水交替注入压裂增注设计

Design on Fracturing and Augmented Injection in CO_2-Water Alternate Flooding in Tight Reservoirs

综合考虑采收率、经济效益与埋存量研究了中低渗油藏CO_2驱压裂增注设计优化方法。首先,采用响应面法综合考虑储层特征、压裂设计与水气交替3方面6种因素,设计了满足需要的少量代表性CO_2驱方案,生成了方案经济净现值、埋存量指标与各因素之间的预测模型,可以快速、直观的确定针对单目标的最佳方案。同时,建立了综合考虑CO_2驱经济净现值与埋存量的多目标优化方法,可以迅速的确定各因素在不同水平组合情况下实现不同设计目标时的最优CO_2驱方案。研究表明:裂缝长度适中、缝高较大、水气比较小时能够获得CO_2方案经济效益与埋存量的综合最优。

Considering recovery, economic benefits and storage capacity, design on fracturing and augmented injection in CO2-water alternate flooding in reservoirs with low to medium permeability was optimized. Six factors in three aspects of reservoir characteristics, fracturing design and alternation of water and gas were analyzed by response surface method, CO2 flooding scheme with a few representative was designed, the forecast model of scheme economic net present value, buried storage index and other factors was established, which can quickly and visually determine the best scheme aiming at single-objective. At the same time, multi-objective optimization method considering CO2 flooding economic net present value and storage capacity was developed, which can determine the best CO2 under different combination of various factors for achieving different design goals. The results showed that the co-optimization of CO2 flooding scheme economic benefits and storage could be achieved under moderate fracture length, greater fracture height and low water-gas ratio.