CO2驱提高采收率技术效果的影响因素研究

The impact of heterogeneity on CO2 flooding improving recovery

CO2驱油技术是国外一项成熟的提高采收率方法,受到世界各国油田的广泛关注。非均质性作为CO2驱重要的油藏和操作参数,对CO2驱提高原油采收率的影响很大。安默德(Ahmed)等人通过敏感性分析研究了主要参数对CO2驱采收率和产量的影响。研究结果显示,在不同非均质性条件下,在合理的注入速率下,采用五点法井网,单井控制面积0.48km2,短周期WAG,水平井段尽量位于产层下部,长度与井距相等,可获得最大采收率。美国朗之利韦伯油田是世界第三大CO2驱油田,从1986年开始实施至今仍然在产,后期CO2气窜严重,通过非均质性研究,调整各项参数,并尝试泡沫和凝胶调剖等技术,取得较好开发效果。国外在CO2驱油技术的研究方法和手段上取得较大进展,对我国一些油田开展的CO2驱油技术研究具有重要的指导和借鉴意义。

CO2 flooding is a mature EOR technology that attracts wide attention in the world.Heterogeneity,as an important index for reservoir description and performance,has a great impact on improving recovery of CO2 flooding.Ahmed et al.studied main factors that affect CO2 flooding recovery and production.The study shows that the best recovery can be achieved under different heterogeneity condition with reasonable injection rate,five-spot well pattern,single well controlling area of 0.482,short WAG,and horizontal wells that locate in the lower part of the formation and has the same length with well distance.Rangely oilfield is the third biggest CO2 flooding oilfield.the oilfield was put in production in 1986 and it is still producing.In the late stage of production severe CO2 channeling took place.After heterogeneity study,some factors were adjusted,and foam and gel conformance control were tried,and the result was favorable.Big improvements are made with research method and technology of CO2 abroad,and some can be reference and lessons to the CO2 flooding technology in China.