凝析气藏注CO_(2)提高采收率机理物理模拟  

Physical simulation of EOR mechanism by CO_(2) injection for condensate gas reservoir

作　　者：田巍[1,2] TIAN Wei(Research Institute of Petroleum Exploration&Production,Zhongyuan Oilfield Company,SINOPEC,Puyang 457001,China;Working Station for Postdoctoral Scientific Research of Zhongyuan Oil Field Company Ltd.,Puyang 457001,China)

机构地区：[1]中国石化中原油田分公司勘探开发研究院,河南濮阳457001 [2]中国石化中原油田分公司博士后科研工作站,河南濮阳457001

出　　处：《天然气地球科学》2021年第10期1592-1600,共9页Natural Gas Geoscience

基　　金：河南省博士后基金“深层高压低渗油藏CO_(2)驱注气能力变化及调整对策”(编号:2018120)资助.

摘　　要：为深入研究凝析气藏注CO_(2)提高采收率机理,应用室内实验手段开展了CO_(2)对凝析气藏流体物性的影响实验。结果表明:注CO_(2)降低了凝析气的露点压力,降低幅度随注入量增加越来越大,注入0.4倍时的下降幅度达到了15.42%;CO_(2)注入倍数较小时,对凝析油以溶解、降黏、膨胀作用为主,凝析油膨胀体积的增量是萃取产出凝析油体积的9倍以上,溶解气油比和相对密度随注入倍数增加而增加;CO_(2)注入倍数较高时以萃取作用为主,生产气油比迅速增加,凝析油相对密度越来越大,采出程度达83%以上。在实际地层条件下,注CO_(2)开发,在远井区主要发挥降低露点压力的作用,并将露点线向产出井推移;在过渡带初期以溶解膨胀为主,压缩了该区带范围,后期主要为萃取作用,将液动线向产出井推进,缩小了近井带范围;在近井带初期主要为驱替作用形成气流通道,中后期主要为溶解、膨胀、携带和萃取作用。综合以上,凝析气藏注CO_(2)开发压缩了气液两相区,可大幅提高凝析气藏采收率。研究成果为凝析气藏的注CO_(2)开发和技术推广提供了重要的技术支撑。In order to further study the mechanism of CO_(2) injection to enhance the recovery of condensate gas reservoir,experiments of the fluid properties of condensate gas reservoir affected by CO_(2) have been carried out.The results show that the dew point pressure of the condensate reservoir is reduced by injecting CO_(2),and the reduction rate increases with the increase of injection volume.The larger the injection volume,the faster the dew point pressure decreases,a 15.42%drop while injecting 0.4 HCPV CO_(2).With a smaller injection HCPV CO_(2),the effect on condensate oil is mainly dissolution,viscosity reduction and expansion.The increment of the condensate oil expansion volume is more than 9 times that of the extracted condensate oil volume,and the dissolved GOR and relative density will increase as the injection HCPV goes up.with a higher CO_(2) injection HCPV,extraction plays a major role,the production GOR increases rapidly,a growing number of the relative density of condensate oil,and the recovery percent reaching more than 83%.Under the actual formation condition,with the development of CO_(2) injection,which mainly reduces dew point pressure in the far well area,and pushes the dew-point-line to the producing well direction.In the early stage of the transition zone,dissolution expansion is the main factor,which compresses the zone area.In the later stage,extraction is the main factor,which pushes the hydraulic line towards the producing well and reduces the zone area near the well.In the early stage near the well zone,the flow channels are mainly formed by displacement,and in the middle and late stage,the flow channels are mainly formed by dissolution,expansion,transport and extraction.In conclusion,the development of CO_(2) injection in condensate gas reservoir compresses the area of gas-liquid two-phase zone,which can greatly enhance the recovery of condensate gas reservoir.The research results provide important technical support for CO_(2) injection development and technical extension of condensate gas

关 键 词：凝析气藏 注CO_(2) 露点压力 膨胀 提高采收率. 

分 类 号：TE37[石油与天然气工程—油气田开发工程]