中东碳酸盐岩储集层高效酸压用微乳酸性能评价  

Performance evaluation of microemulsion acid for integrated acid fracturing in Middle Eastern carbonate reservoirs

作　　者：王云金 周福建 苏航[3] 李源 于馥玮 董壬成 王庆 李俊键[1,2] WANG Yunjin;ZHOU Fujian;SU Hang;LI Yuan;YU Fuwei;DONG Rencheng;WANG Qing;LI Junjian(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China;MOE Key Laboratory of Petroleum Engineering,China University of Petroleum,Beijing 102249,China;China National Oil and Gas Exploration and Development Corporation,Beijing 100034,China;PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;University of Texas at Austin,Austin TX78712,USA)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]中国石油大学(北京)教育部重点实验室,北京102249 [3]中国石油国际勘探开发有限公司,北京100034 [4]中国石油勘探开发研究院,北京100083 [5]美国德克萨斯大学奥斯汀分校,奥斯汀TX78712,美国

出　　处：《石油勘探与开发》2023年第5期1041-1048,共8页Petroleum Exploration and Development

基　　金：国家科技重大专项(2017ZX05009-005-003);国家自然科学资助基金面上项目(52174045);中国工程院战略咨询项目(2018-XZ-09);中国石油天然气集团有限公司-中国石油大学(北京)战略合作科技专项(ZLZX2020-01)。

摘　　要：针对中东碳酸盐岩储集层特点,研发低黏度、具有适当缓速能力、可在线混配的微乳酸,利用旋转圆盘、多级交替注入酸压、岩心驱替同步CT扫描实验,开展与盐酸、胶凝酸、乳化酸、表面活性剂胶束酸4种常规酸液体系的对比实验,明确裂缝面的微观刻蚀特征与导流规律,定量评价残酸水侵及返排过程中饱和度场的变化规律与油相相对渗透率的恢复程度。研究表明:在微乳酸油核中添加带负电的极性剂后,可增强其在灰岩表面的吸附能力,显著降低H+传质速度,同时负电油核与Ca^(2+)盐不混溶,微乳酸整体结构不会被反应过程中产生的Ca^(2+)盐破坏,吸附性能可调且微乳结构稳定。微乳酸沿裂缝壁面垂向渗透能力强,可渗入裂缝壁面深部形成网状刻蚀,极大改善裂缝周围储集层的渗透能力,且在高闭合压力下可保持较高的导流能力。微乳酸残酸与原油混合后形成微乳液,微乳液、油、水三者之间处于近混溶状态,基本无水锁现象,返排阻力低,残酸返排率和油相相对渗透率恢复程度高。Considering the characteristics of carbonate reservoirs in the Middle East,a low-viscosity microemulsion acid that can be prepared on site and has an appropriate retardation ability was developed.It was compared with four conventional acid systems(hydrochloric acid,gelled acid,emulsified acid and surfactant acid)through experiments of rotating disk,multistage acid fracturing and core flooding with CT scanning.The micro-etching characteristics and conductivity of fracture surfaces were clarified,and the variation of saturation field during water invasion and flowback of spent acid and the recovery of oil phase relative permeability were quantitatively evaluated.The study shows that the addition of negatively charged agent to the oil core of microemulsion acid can enhance its adsorption capacity on the limestone surface and significantly reduce the H+mass transfer rate.Moreover,the negatively charged oil core is immiscible with the Ca^(2+)salt,so that the microemulsion acid can keep an overall structure not be damaged by Ca^(2+)salt generated during reaction,with adjustable adsorption capacity and stable microemulsion structure.With high vertical permeability along the fracture walls,the microemulsion acid can penetrate into deep fracture wall to form network etching,which helps greatly improve the permeability of reservoirs around the fractures and keep a high conductivity under a high closure pressure.The spent microemulsion acid is miscible with crude oil to form microemulsion.The microemulsion,oil and water are in a nearly miscible state,with basically no water block and low flowback resistance,the flowback of spent acid and the relative permeability of oil are recovered to a high degree.

关 键 词：中东地区 碳酸盐岩 微乳酸 酸岩反应 导流能力 残酸返排 渗透率恢复 

分 类 号：TE344[石油与天然气工程—油气田开发工程]