摘要
通过国内外多个油田水驱后实施CO2驱的矿场实例研究,发现注入CO2后很多油井存在含水率下降的现象;这种现象发生在CO2驱的整个开发阶段,包括注气初期阶段CO2未到达生产井、生产井见气阶段以及高气油比阶段。重点讨论了生产井见气前的开发规律,在该阶段油藏内以油水两相渗流为主,不受三相渗流作用的影响。通过现场动态反应并结合室内细管和长岩心实验,揭示了CO2与油、水2种介质的相互作用,得到了两个结论:第一是始于低含水阶段的CO2驱过程中气体穿越地层水驱替地层油到达生产井;第二是始于高含水阶段的CO2驱替规律在不同级别低渗透岩心中的差异非常明显:对于特低渗岩心,CO2突破前的采出程度占CO2驱总采出程度的73.27%,CO2突破后的采出程度占26.73%,对于一般低渗岩心,CO2突破前的采出程度仅占CO2驱总采出程度的16.72%,而CO2突破后的采出程度占到了CO2驱总采出程度的83.28%。
Through the study of many domestic and abroad field examples of CO2 flooding after water flooding,it is discovered that after the injection of CO2,the water cut of many production wells decreases sharply,and this phenomenon happens across the whole development phase,including the early stage of CO2 injection which the CO2 displacing front doesn＇t reach production wells,the stage of little gas producing,and the stage of high gas-oil ratio.We take emphasis on discussing the development rules of low permeability reservoir before the breakthrough of CO2,and on this stage oil-water two-phase fluid flow is the main flow type,and three-phase flow does not exist.The reason is that a majority of the injected CO2 dissolved in local oil and water.According to the actual oilfield dynamic response and the results of in-house slim tube and long core flooding experiment,we explain the action between CO2 and oil-water system,finally gain two conclusions.The first is that gas can drive crude oil reaching producers by traveling through local water.The second is that the displacement law is obviously different in different low permeability cores when CO2 flooding starting from high water cut stage,for the special low permeability cores,the oil recovery before CO2 breaking accounted for CO2 total recovery of 73.27%,and after CO2 breaking the recovery accounted for 26.73%.But for the average low permeability cores,the oil recovery before CO2 breaking only accounted for CO2 total recovery of 16.72%,and after CO2 breaking the recovery accounted for 83.28%.
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2011年第4期1028-1032,1047,共6页
Journal of Jilin University：Earth Science Edition
基金
国家重大专项项目(2008ZX05000-016-04)
关键词
CO2驱
低渗透
室内实验
含水
开发规律
油气
CO2 flooding
low permeable
in-house experiments
water cut
development rules
petroleum
