CO2压裂后近缝带烃类的相态特征  

PHASE STATE RESEARCH ON HYDROCARBONS AROUND FRACTURE AFTER CO_2 FRACTURING

作　　者：位云生[1] 胡永全[2] 张啸枫[1] 阮刚[3] 贾成业[3] 

机构地区：[1]中国石油勘探开发研究院鄂尔多斯分院,100083 [2]西南石油大学 [3]中国石油大港油田公司

出　　处：《天然气工业》2008年第11期91-92,共2页Natural Gas Industry

基　　金：四川省天然气开采重点实验室项目“凝析气藏压裂优化设计”(编号:GPL04-09)的资助

摘　　要：CO2压裂与常规水力压裂相比,除具有滤失小、易返排、低伤害等常规优点外,还能降低烃类的露点压力,对易凝析的中间组分产生很强的抽提作用,有效解除了由于温度压力的变化所造成的近缝带凝析油污染。这为提高凝析气藏采收率、制定合理有效的开发手段提供了新的途径。以中原油田白庙凝析气田为例,建立了数值计算模型,研究了CO2压裂停泵时刻其CO2量不同时的凝析气藏近缝带烃类的相态变化及各点凝析油饱和度的变化情况。研究结果表明:CO2气体对凝析气藏烃类的相态影响是CO2压裂优于常规水力压裂的重要原因,且CO2量不同时对烃类相态的影响程度存在显著差异。这为现场实际结果的解释及优化凝析气藏CO2压裂的气体用量和压裂规模提供了理论依据。Compared with conventional hydraulic fracturing,CO2 fracturing has many advantages:in addition to traditional virtues of little filtration,easy flowback and low damage etc.,CO2 can also decrease dew point pressure of hydrocarbons and extract heavily intermediate component condensated easily,which can effectively relieve the condensate oil pollution around fracture caused by change of temperature and pressure in condensate gas reservoirs.It enhances condensate gas recovery and offers a new way to reasonable and effective development of condensate gas reservoirs.A well in the Baimiao condensate gas reservoir,the Zhongyuan oil field,is taken as an example,and a numerical model is formed to research on hydrocarbons phase state and condensate oil saturation of each point at the time of pumping off in CO2 fracturing when molecule percentage of CO2 is different.The results indicate that the important reason why CO2 fracturing is better than conventional hydraulic fracturing is CO2 gas effect on hydrocarbons phase state in condensate gas,and there is obvious difference among the degrees of effect on hydrocarbons phase state when molecule of CO2 is different.The results offer theoretical reference to interpret the actual result and optimize gas volume and fracturing scale in condensate gas reservoir fracturing.

关 键 词：二氧化碳 凝析油气田 裂缝(岩石) 相态 饱和度 白庙气田 

分 类 号：TE357[石油与天然气工程—油气田开发工程]