基于核磁共振测试的低渗亲水岩心静态渗吸特征  

Spontaneous imbibition characteristics of the low-permeability water-wet core based on the NMR test

作　　者：董大鹏[1,2] 李斌会 苑盛旺[1,2] 李江涛 DONG Dapeng;LI Binhui;YUAN Shengwang;LI Jiangtao(Exploration and Development Research Institute of Daqing Oilfield Co Ltd,Daqing 163712, China;Heilongjiang Key Laboratory of Reservoir Physics & Fluid Mechanics in Porous Medium, Daqing 163712,China;MOE Key Laboratory of Continental Shale Hydrocarbon Accumulation and Efficient Development,Daqing 163318,China)

机构地区：[1]大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712 [2]黑龙江省油层物理与渗流力学重点实验室,黑龙江大庆163712 [3]东北石油大学陆相页岩油气成藏及高效开发教育部重点实验室,黑龙江大庆163318

出　　处：《大庆石油地质与开发》2021年第2期60-65,共6页Petroleum Geology & Oilfield Development in Daqing

基　　金：国家自然科学基金项目“考虑污染条件下页岩气储层气—水两相渗流机理研究”(51474070)。

摘　　要：低渗透储层岩性致密、孔喉细小,导致毛管力引起的压裂液渗吸作用强,有助于提高原油采收率。基于室内静态渗吸实验,结合核磁共振仪定量刻画了低渗亲水岩心内的油水分布,并进一步分析了不同尺度孔隙渗吸速率和渗吸采出程度。结果表明:低渗亲水岩心渗吸首先发生在小孔隙中,其渗吸采出程度达到47.92%;大孔隙的渗吸采出程度仅为小孔隙的1/2;渗吸第1天速度最大,渗吸作用在第6天后基本停止,渗吸采收率为24.23%;油水两相在小孔隙与大孔隙中流动机理的差异,导致小孔隙的渗吸采出程度随着界面张力的增加而增加,而大孔隙则相反。研究成果从微观角度量化了压裂液在低渗储层孔喉中的渗吸行为,可为低渗油藏压后关井时间优化和压裂液界面张力优选提供借鉴。The low-permeability reservoir is characterized by tight rock and small pore-throat,as well as strong imbibition effect of fracturing fluid caused by the capillary force,which is beneficial to enhance the oil recovery.Based on the indoor imbibition experiment and combined with the nuclear magnetic resonance instrument,the oil-water distribution in the low-permeability water-wet core was quantitatively characterized,and the imbibition rate and recovery factor at different scales of the pores were further analyzed.The results show that the imbibition process takes place first in the small pores and the imbibition recovery of the small pores is up to 47.92%,which is the double of that in the large pores.The imbibition speed is the highest on the first day and then the imbibition nearly stops on the sixth day with the oil recovery by spontaneous imbibition of 24.23%.Due to the different mechanisms for the oil-water two-phase flow in the small pores and large pores,the imbibition recovery of the small pores increases with the growth of the capillary force;while for the large pores,the rule is just opposite.The study achievements have quantitatively characterized the imbibition behaviors of the fracturing fluid in the low-permeability reservoir from microscopic perspective,which provide the guidance for the optimizations of shut-in time after the hydraulic fracturing and interfacial tension of the fracturing fluid in the low-permeability oil reservoir.

关 键 词：静态渗吸 低渗 核磁共振 渗吸采收率 渗吸速率 

分 类 号：TE341[石油与天然气工程—油气田开发工程]