CO_(2)吞吐提高凝析气藏凝析油采收率实验研究  

Experimental Study on Improving Condensate Oil Recovery by CO_(2) Huff and Puff in Condensate Gas Reservoirs

作　　者：王小雨 任皓洁 广怡初 张娟 殷晓霞 马斌 WANG Xiaoyu;REN Haojie;GUANG Yichu;ZHANG Juan;YIN Xiaoxia;MA Bin(Laojunmiao Oil Production Plant,PetroChina Yumen Oilfield Company,Jiuquan,Gansu,735019,China)

机构地区：[1]中国石油玉门油田分公司老君庙采油厂,甘肃酒泉735019

出　　处：《石油钻探技术》2025年第1期86-93,共8页Petroleum Drilling Techniques

基　　金：国家重点研发计划项目“CO_(2)驱油技术及地质封存安全监测”(编号:2018YFB0605500)资助。

摘　　要：注CO_(2)提高天然气和凝析油采收率技术目前仍处于发展阶段,CO_(2)的注入方式、注入时机以及CO_(2)与储层流体之间的相互作用机理尚不明确。通过开展凝析气藏注CO_(2)定容衰竭实验和油气界面张力测定实验,在明确最大反凝析压力及液量和CO_(2)-凝析油相互作用方式的基础上,提出了逐轮增量注CO_(2)的吞吐方法,并采用全直径岩心实验评价了吞吐效果及CO_(2)储存比例。研究表明,凝析气藏注入CO_(2)后,其露点压力、最大反凝析压力和凝析油体积均不断降低,临界点向左下角移动,两相包络区向内收缩,流体组分变轻;CO_(2)与凝析油之间需经多次接触,才能逐步混相,CO_(2)压力越高,达到混相所需接触的次数越少;4轮增量CO_(2)吞吐凝析油的采收率分别为1.2%,14.4%,25.8%和3.6%,比自然衰竭凝析油采收率累计提高了45.0百分点;CO_(2)储存比例随吞吐次数增多而降低,分别为82.2%,72.1%,46.4%和9.2%,最优CO_(2)吞吐次数应不超过3次;CO_(2)吞吐效果受CO_(2)注入压力及岩心系统压力的影响,当CO_(2)注入压力低于最小混相压力时,不利于CO_(2)吞吐和储存。研究结果可为凝析气藏高效开发、改善反凝析伤害提供参考和借鉴。The application of CO_(2) injection to improve the recovery of natural gas and condensate oil is still in the development stage.The CO_(2) injection mode,injection time,and the interaction mechanism between CO_(2) and reservoir fluid are not clear.Through the constant volume depletion experiment of CO_(2) injection into condensate gas reservoirs and the measurement experiment of oil-gas interfacial tension,a stepwise incremental CO_(2) huff and puff method was proposed on the basis of determining the maximum retrograde condensate pressure,liquid volume,and CO_(2)-condensate oil interaction mode.In addition,the huff and puff effect and CO_(2) storage ratio were evaluated by full diameter core experiment.The results show that after the CO_(2) is injected into the condensate gas reservoir,the dew point pressure,the maximum retrograde condensate pressure,and the condensate oil volume are continuously reduced,and the critical point moves to the lower left corner.The two-phase envelope area shrinks inward,and the fluid components become lighter.The phase mixing between CO_(2) and condensate oil can be achieved gradually only after multiple contacts.A higher CO_(2) pressure indicates fewer contacts required to achieve the phase mixing.The condensate oil recovery after four rounds of incremental CO_(2) huff and puff is 1.2%,14.4%,25.8%,and 3.6%,respectively,which is 45.0 percentage points higher than that after natural depletion.The proportion of CO_(2) storage decreases with the increase in huff and puff times,which are 82.2%,72.1%,46.4%,and 9.2%,respectively.CO_(2) huff and puff times should be controlled within 3 to achieve the optimal effect.The CO_(2) huff and puff effect is mainly affected by CO_(2) injection pressure and core system pressure.When the CO_(2) injection pressure is lower than the minimum miscible pressure(MMP),it is not conducive to CO_(2) huff and puff and storage.The research results provide a reference for the efficient development of condensate gas reservoirs and the improvement of retrograde con

关 键 词：凝析气藏 凝析油 二氧化碳吞吐 二氧化碳储存 最小混相压力 

分 类 号：TE357.45[石油与天然气工程—油气田开发工程]