玛湖凹陷砾岩储层CO_(2)前置压裂工艺支撑剂嵌入特征  

Proppant embedment characteristics of CO_(2) pre⁃pad fracturing techique for conglomerate reservoir in Mahu Sag

作　　者：刘凯新 杜布戈 李杰[1] 董景锋 王斌[1] 王笑涵 彭岩 LIU Kaixin;DU Buge;LI Jie;DONG Jingfeng;WANG Bin;WANG Xiaohan;PENG Yan(Research Institute of Engineering Technology,PetroChina Xinjiang Oilfield Company,Karamay 834099,China;College of Petroleum Engineering,China University of Petroleum(Beijing),Beijing 102249,China)

机构地区：[1]中国石油新疆油田分公司工程技术研究院,新疆克拉玛依834099 [2]中国石油大学(北京)石油工程学院,北京102249

出　　处：《大庆石油地质与开发》2025年第2期68-78,共11页Petroleum Geology & Oilfield Development in Daqing

基　　金：国家自然科学基金项目“致密储层缝内变载荷驱动裂缝疲劳扩展机理研究”(51974356);中国石油大学(北京)科研基金项目“砾岩油藏变载荷压裂井筒完整性失效力学机理研究”(2462021YXZZ012)。

摘　　要：玛湖凹陷部分砾岩储层水基压裂后导流能力损失严重,CO_(2)前置压裂工艺应用潜力巨大,但CO_(2)前置压裂后支撑剂嵌入行为表征尚不明确。为研究CO_(2)前置压裂支撑剂嵌入特征及其机理,选取上乌尔禾组砾岩开展支撑剂嵌入实验,表征储层条件下水基和CO_(2)前置的支撑剂嵌入特征差异,建立数值模型对比导流能力,利用双电层理论分析CO_(2)前置减轻嵌入的作用机理。结果表明:CO_(2)前置压裂工艺在保证携砂能力的同时,可以减轻黏土水化导致的支撑剂嵌入;与水基压裂相比,CO_(2)前置深度为[0.15,0.25)mm的嵌入坑的相对频率降低了13%~70%,而前置深度为[0.25,0.4)mm嵌入坑的相对频率降幅达78%,导流能力可提升24%~30%;CO_(2)前置对低黏土矿物含量试件的作用效果最好,随黏土矿物含量升高效果逐渐减弱;CO_(2)前置缩短了水-岩接触时间,“毛细捕获”及吸水干燥效应减小了弱结合水膜吸收自由水能力,减弱了黏土水化膨胀,弱化了支撑剂嵌入程度。CO_(2)前置压裂工艺有助于水敏储层的高效开采。Some conglomerate reservoirs in Mahu Sag have serious decline of fracture conductivity after water-based fracturing.CO_(2) pre-pad fracturing has huge potential of application,but the behavior characterization of proppant embedment after CO_(2)pre-pad fracturing is unclear.In order to clarify proppant embedment characteristics and mech-anism of CO_(2) pre-pad fracturing,conglomerate rocks of Upper Wuerhe Formation are selected for proppant embed-ment experiment to characterize difference of proppant embedment characteristics between water-based fracturing and CO_(2) pre-pad fracturing in reservoir conditions.Numerical model is established to compare conductivity.Mecha-nism of reducing embedment by CO_(2) pre-pad fracturing is analyzed via electric double layer theory.The results show that CO_(2) pre-pad fracturing can reduce proppant embedment caused by clay hydration while maintaining proppant carrying capacity.Compared with water-based fracturing,the relative frequency of embedment pits at[0.15,0.25)mm depth with CO_(2) pre-pad fracturing is reduced by 13%~70%,while the relative frequency of embedment pits at[0.25,0.4)mm depth is reduced by 78%,and conductivity is increased by 24%~30%.CO_(2) pre-pad fracturing has the optimal effect on samples with low clay mineral content,and the effect decreases with the increase of clay mineral content.CO_(2) pre-pad fracturing shortens water-rock contact time,and“capillary trapping”and“water dry”reduce capacity of weakly bound water film absorbing free water,weakening hydration expansion of clay and weakening proppant embedment degree.CO_(2)pre-pad fracturing contributes to efficient exploitation of water-sensitive reservoirs.

关 键 词：CO_(2)前置压裂 水敏 黏土矿物 支撑剂嵌入 砾岩储层 玛湖凹陷 

分 类 号：TE357.1[石油与天然气工程—油气田开发工程]