摘要
为了明确体积压裂过程中基质孔隙压力与压裂液施加在裂缝端面的压力之间存在的缝端压差对页岩储层渗吸排驱效果的影响,以长7页岩储层岩心为研究对象,开展页岩油高压补能和稳压焖井过程中,不同缝端压差下的渗吸排驱模拟试验,并借助动态核磁共振检测、实时压力监测和可视化图像分析等手段,阐释缝端压差对页岩储层渗吸排驱效果的影响。结果表明:高压补能阶段存在明显的逆压差逆向渗吸作用,且随着缝端压差的不断增大,高压补能阶段的排液效率逐渐增加,其中以小孔隙中的渗吸排驱作用为主(0~6 MPa时,小孔隙的排液效率分别为33.31%、29.51%、35.65%和64.89%);稳压焖井阶段小孔隙中由于液体排驱压力降低,逆压差逆向渗吸现象不明显,排液过程仍以毛管力作用下的逆向渗吸为主,同时部分大孔隙中的原油渗入小孔隙当中。
The pressure difference between the pressure exerted by fracturing fluid and the pressure of reservoir matrix at the ends of the fractures can have an important influence on oil-water imbibition and displacement.In this study,using cores collected from Chang 7 shale formation,simulation experiments of imbibition and displacement under different fracture end pressure difference were carried out under conditions of supplement formation energy with high pressure injection of fracturing fluid and well shut-in with constant pressure.In the experiments,a dynamic nuclear magnetic resonance(NMR)technique,real-time pressure detection,and visual image analysis were applied to analyze and interpret the influence mechanisms of the fracture end pressure difference.The results show that reverse differential pressure with reverse imbibition can be obviously observed,especially in the process of supplement formation energy by the fracturing fluid,in which,with the increase of the fracture end pressure difference,the efficiency of imbibition and displacement gradually increases.The efficiency of imbibition and displacement is dominated in the micro pores(at 0-6 MPa,the imbibition and displacement efficiency are 33.31%,29.51%,35.65%and 64.89%respectively).In the process of well shut-in with a constant pressure,the reverse differential pressure imbibition is reduced due to the weakening of the differential pressure in micro pores,and the imbibition and displacement process are still dominated by reverse imbibition with capillary force,while oil in large pores can imbibe into micro pores.
作者
何延龙
黄海
唐梅荣
倪军
李华周
TAYFUN Babadagli
张轩诚
HE Yanlong;HUANG Hai;TANG Meirong;NI Jun;LI Huazhou;TAYFUN Babadagli;ZHANG Xuancheng(School of Petroleum Engineering,Xi'an Shiyou University,Xi'an 710065,China;Engineering Research Center of Ministry of Education for the Development and Treatment of Western Low-Extra Low Permeability Reservoirs,Xi'an 710065,China;Natural Gas Evaluation Project Department of Changqing Oilfield,CNPC,Xi'an 710065,China;Shaanxi Yanchang Petroleum(Group)Company Limited,Xi'an 710065,China;School of Mining and Petroleum Engineering,Faculty of Engineering,University of Alberta,Edmonton T6G1H9,Canada)
出处
《中国石油大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第6期114-122,共9页
Journal of China University of Petroleum(Edition of Natural Science)
基金
国家自然科学基金项目(52474040,52474042,52004216)
陕西省杰出青年科学基金项目(2022JC-37)
陕西省重点研发计划项目(2024GX-YBXM-496)
陕西省创新能力支撑计划项目(2023-CX-TD-31)
陕西省高校青年创新团队项目(油气资源绿色开发与多能互补创新团队)。
关键词
缝端压差
页岩油储层
动态渗吸
核磁共振
fracture end pressure difference
shale oil reservoir
dynamic imbibition
nuclear magnetic resonance
