致密砂岩油藏CO_(2)吞吐孔喉结构变化规律研究  

Study on the change law of pore throat structure by CO_(2) huff and puff in tight sandstone reservoirs

作　　者：赵金省[1,2] 宋语桐 张庆祝 徐洋 胡海文 李斌[5] 许明勇 居迎军 ZHAO Jinsheng;SONG Yutong;ZHANG Qingzhu;XU Yang;HU Haiwen;LI Bin;XU Mingyong;JU Yingjun(School of Petroleum Engineering,Xi’an Shiyou University,Xi’an 710065,China;Research Institute for Carbon Neutrality Future Technology,Xi’an Shiyou University,Xi’an 710065,China;Xi’an Changqing Chemical Group Co.,Ltd.,Xi’an 710018,China;Drilling&Production Engineering Technology Research Institute,CNPC Chuanqing Drilling Engineering Co.,Ltd.,Xi’an 710018,China;Completion Test Management Center of Sinopec Northwest Oilfield Company,Xinjiang Luntai 841600,China;No.6 Oil Production Plant,PetroChina Changqing Oilfield Company,Shaanxi Dingbian 718606,China)

机构地区：[1]西安石油大学石油工程学院,西安710065 [2]西安石油大学碳中和未来技术研究院,西安710065 [3]西安长庆化工集团有限公司,西安710018 [4]中国石油川庆钻探工程有限公司钻采工程技术研究院,西安710018 [5]中国石化西北油田分公司完井测试管理中心,新疆轮台841600 [6]中国石油长庆油田分公司第六采油厂,陕西定边718606

出　　处：《非常规油气》2025年第2期54-63,共10页Unconventional Oil & Gas

基　　金：国家自然科学基金面上项目“致密砂岩油藏CO_(2)吞吐多尺度流、固物性变化机理及对吞吐效果的影响”(52174031);陕西高校青年创新团队“非常规油气藏CO_(2)利用及埋存创新团队”。

摘　　要：为明确CO_(2)吞吐对致密砂岩油藏储层物性的影响,结合核磁共振测试技术,定量评价了不同注入压力、不同焖井时间以及不同注入方式下CO_(2)吞吐实验对岩心孔隙度、渗透率及孔喉结构的影响,揭示了CO_(2)吞吐过程中致密砂岩微观物性的变化机理。研究结果显示,目标区块CO_(2)吞吐过程中溶蚀作用明显,孔隙度变化率和渗透率变化率与注入压力呈正相关,当压力达到CO_(2)与原油最小混相压力时,增幅最大,分别达到78.90%和8.75%;孔隙度变化率和渗透率变化率与焖井时间呈先增大后减小的趋势,当焖井时间到6 h时,溶蚀作用最强烈,两者的变化率分别达到34.79%和8.22%;从注入方式分析,岩心初始渗透率与渗透率变化率相关性最大。通过核磁共振T_(2)谱分布,对比分析实验前后的孔喉半径变化,发现不同注入压力、不同焖井时间和不同注入方式下的变化规律基本一致,小孔及微孔孔隙体积变大,变化程度可达46.42%,孔喉连通性得到改善,中孔孔隙体积变小,大孔孔隙体积减小甚至直接消失。In order to clarify the influence of CO_(2) huff and puff on the physical properties of core reservoirs in tight sandstone reservoirs,combined with nuclear magnetic resonance testing technology,the effects of CO_(2) huff and puff experiments on core porosity,permeability and pore throat structure under different injection pressures,simmering time and injection methods were quantitatively evaluated,and the change mechanism of microscopic physical properties of tight sandstone during CO_(2) huff and puff was revealed.The results show that the dissolution effect of CO_(2) in the target block is obvious during the huff and puff,and the change rate of porosity and permeability is positively correlated with the injection pressure,and when the pressure reaches the minimum miscible pressure of CO_(2) and crude oil,the increase is the largest,reaching 78.90% and 8.75%,which shows a trend of first increasing and then decreasing with the simmering time,and the dissolution effect is the strongest when the simmering time reaches 6 hours,with the change rates reaching 34.79% and 8.22%.From the analysis of injection mode,the initial permeability of the core has the greatest correlation with the change of porosity permeability.Through the nuclear magnetic resonance T_(2) spectral distribution,the changes of pore throat radius before and after the experiment were compared and analyzed,and it was found that the change law under different injection pressures,simmering time and injection mode was basically the same,the pore volume of small pores and micropores became larger,and the change degree could reach 46.42%,the pore throat connectivity was improved,the pore volume of mesopores became smaller,and the pore volume of macropores decreased or even disappeared directly.

关 键 词：CO_(2)吞吐 孔喉结构 核磁共振 注入压力 焖井时间 

分 类 号：TE37[石油与天然气工程—油气田开发工程]