摘要
针对江汉盆地潜江凹陷盐间页岩油储层注水开发造成盐溶解及地层坍塌问题,通过岩心渗吸-驱替实验,利用核磁共振、扫描电镜等方法,从微观和宏观角度研究了不同矿化度注入水对岩心孔隙结构、渗流能力的影响。结果表明:在中矿化度水中渗吸的岩心T2(弛豫时间)谱的右峰随渗吸时间逐渐向左移动,岩心发生水敏效应,导致孔隙结构变小;在超纯水中渗吸的岩心T2谱峰的右翼随渗吸时间逐渐向右移动,表明注入水逐渐向较大孔隙运移,岩心内可溶盐类发生溶解,导致孔隙结构变大。经中矿化度水驱替后,盐间页岩油岩心渗透率降低20. 45%,产出液中离子含量少量增加;经低矿化度水和超纯水驱替后,岩心渗透率分别增大34. 76%、61. 15%,产出液中离子含量均大量增加。该结果解释了现场注水开发造成地层坍塌的现象,对盐间页岩油藏注水开发生产具有一定理论指导意义。
In order to improve the salt dissolution and formation collapse caused by waterflooding development of the inter-salt shale oil reservoir in the Qianjiang Sag of Jianghan Basin,the effects of injection water salinity on pore structure and seepage capacity were investigated from micro and macro perspectives by laboratory core imbibition-displacement experiment,nuclear magnetic resonance and scanning electron microscopy. Result indicates that the right peak of T2 spectrum for the core samples with imbibition in the medium-salinity water shifts to the left with imbibition time. The water sensitivity effect of core sample results in the shrink of pore structure. The right wing of T2 spectrum for the core sample with imbibition in the ultrapure water shifts to the right with imbibition time,which indicates that the injection water gradually migrates to the larger pores,resulting on an expand of pore structure.After flooding with medium-salinity water,the permeability of inter-salt shale oil core sample was decreased by 20. 45%,and the ion convent in the produced fluid shows a slight increase. After flooding with low-salinity water and ultrapure water,the permeabilities of core sample were increased by 34. 76% and 61. 15% respectively,and the ion convent in the produced solution shows a significant increase. This research could explain the formation collapse caused by on-site waterflooding development and could also provide certain theoretical guidance for the waterflooding development of inter-salt shale oil reservoirs.
作者
李兆敏
赵艳玲
王海涛
赵清民
鹿腾
徐正晓
Li Zhaomin;Zhao Yanling;Wang Haitao;Zhao Qingmin;Lu Teng;Xu Zhengxiao(China University of Petroleum(East China),Qingdao,Shandong 266580,China;Sinopec Research Institute of Petroleum Exploration and Production,Beijing 100089,China)
出处
《特种油气藏》
CAS
CSCD
北大核心
2020年第2期131-137,共7页
Special Oil & Gas Reservoirs
基金
国家自然科学基金“致密油储层纳米流体渗吸驱油机制研究”(51604292)。
关键词
注水
矿化度
储层物性
渗吸
驱替
核磁共振
盐间页岩油
water injection
salinity
reservoir physical properties
imbibition
displacement
nuclear magnetic resonance
inter-salt shale oil
