濮城油田沙一段油藏CO₂ /水交替驱提高采收率试验

 Pilot test of enhancing oil recovery by CO₂ and water alternating injection in Es1 reservoir of Pucheng Oilfield

 马平 2 陈林媛³ 王秋梅³ 费明华⁴

西南石油大学石油工程学院，四川 成都 610500 中国石化中原油田分公司采油四厂，河南 濮阳 457071 中国石化中原油田分公司勘探开发科学研究院，河南 濮阳 457001 4中国石化国际石油勘探开发有限公司，北京 100083

水驱废弃的高温高盐油藏，化学驱提高采收率的发展受到限制，为了探索进一步提高油藏采收率的新途径，在濮城油田沙一段水驱废弃油藏开展了CO₂ /水交替驱先导试验。通过细管实验确定了该区CO₂驱的最小混相压力，利用长岩心物理模拟开展了完全水驱后CO₂ /水交替驱替实验。结果表明，该区注CO₂的最小混相压力为18.42 MPa，目前油藏条件下，CO₂ /水交替驱可提高采收率35.89%。现场优选了1个井组开展先导试验，生产动态资料表明，地层压力保持在最小混相压力之上，产出油质变轻，驱替达到了混相，单井最高增油量16 t/d，采出程度提高5.15%。研究表明，CO₂ /水交替驱可以获得比水驱更高的采收率，试验规模可以进一步扩大。

 Enhancing oil recovery by chemical flooding is limited due to high temperature and high salinity of abandoned waterflooding reservoir. In order to probe new methods in enhancing oil recovery, the pilot tests of CO₂ and water alternating injection are carried out in Es₁ reservoir of Pucheng Oilfield which is nearly abandoned. The minimum miscibility pressure of CO₂ flooding is determined by slim tube test. Through the long core physical simulation, a well group is selected to implement the pilot test after completely waterflooding. The result shows that the minimum miscibility pressure of CO₂ injection is 18.42 MPa. At present, the miscibility can be reached the formation pressure and the oil recovery can be improved to 35.89% by CO₂ and water alternating injection. Production data show that formation pressure is over the minimum miscibility pressure. Produced oil turns light and flooding becomes miscible. The maximum oil increment of single well is 16 t and the degree of reserve recovery increases by 5.15%, which shows that the oil recovery can be enhanced by CO₂ and water alternating injection and the test scale can be enlarged.

10.6056/dkyqt201203019