摘要
研究低渗透储层酸岩溶蚀机理,明确泥质含量、酸液浓度等因素对酸液溶蚀效率的影响,对优化酸液选择、提高酸化效果具有重要意义。结合静态溶蚀(矿物岩板,20~60℃)与动态渗流(酸液质量分数1%~5%,岩心渗透率(0.1~1)×10^(-3)μm^(2),泥质含量8%~44%)两种实验模式,分析了盐酸、土酸与乙酸在不同条件下的溶蚀规律;并引入核磁共振在线监测技术,评估了酸液驱替前后孔隙结构变化。研究结果表明:石英耐蚀性强(24 h溶蚀率<3%),而蒙脱石易被溶蚀(24 h溶蚀率可达54.46%),且溶蚀率随温度升高而提升;岩石渗透率、酸液浓度及泥质含量的提升均能增强溶蚀效果,因此高渗透率岩心酸蚀效果优于低渗岩心;5%土酸溶蚀效果最优,可使岩心孔隙度提高14.39%,渗透率提高76.30%。综合认为,泥质矿物(特别是蒙脱石)是影响酸蚀效率的关键因素,对于泥质含量≥20%的低渗砂岩储层,推荐采用5%土酸进行酸化。核磁共振-压汞联用技术的应用使孔隙结构描述精度提升了10%以上。
It is crucial for optimizing acid fluid selection and enhancing acidification effect to investigate the acid rock dissolution mechanism of low-permeability reservoirs and clarify the impact of such factors as shale content and acid fluid concentration on dissolution efficiency.Combining two experimental approaches—static dissolution(mineral rock plate at 20~60℃)and dynamic flow(with acid fluid concentration 1%~5%,core permeability(0.1~1)×10^(-3)μm^(2),and shale content 8%~44%),the dissolution laws of hydrochloric acid,mud acid,and acetic acid were analyzed under various influencing factors.In addition,nuclear magnetic resonance online monitoring technology was introduced to evaluate the changes in pore configuration before and after acid displacement.The results show that quartz exhibits strong acid resistance(dissolution rate<3%after 24 hours),while montmorillonite is easily dissolved(dissolution rate of 54.46%after 24 hours).As the temperature rises,the dissolution rate gradually increases.Increases in rock permeability,acid fluid concentration,and shale content all contribute to enhanced acid dissolution.Therefore,high-permeability cores present better acidizing effect than low-permeability cores.After displacement with 5%mud acid,the optimal dissolution effect is achieved,core porosity is increased by 14.39%and permeability improved by 76.30%.Overall,clay minerals(particularly montmorillonite)are key factors influencing acidizing efficiency.The use of 5%mud acid is recommended for acidizing low-permeability sandstone reservoirs with shale content≥20%.The application of nuclear magnetic resonance-mercury penetration coupling technique improves the accuracy of pore configuration description by over 10%.
作者
王昭凯
牟倩楠
赵红雨
张永波
吕东方
李哲
赵光
WANG Zhaokai;MOU Qiannan;ZHAO Hongyu;ZHANG Yongbo;LV Dongfang;LI Zhe;ZHAO Guang(School of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,Shandong,China;SINOPEC Shengli Oilfield Company,Dongying 257000,Shandong,China;Downhole Operation Company,SINOPEC Shengli Petroleum Engineering Company,Dongying 257000,Shandong,China)
出处
《石油钻采工艺》
北大核心
2025年第4期452-463,共12页
Oil Drilling & Production Technology
基金
国家自然科学基金联合基金项目“海上稠油CO_(2)反应增黏聚表剂驱油体系构建及作用机制”(编号:U23B2087)。
关键词
低渗透砂岩储层
酸化
溶蚀规律
核磁共振
泥质含量
动静态实验
low-permeability sandstone reservoir
acidification
dissolution law
NMR
shale content
dynamic and static experiments
