页岩油储层微观孔隙结构特征及孔隙流体划分  

Microscopic pore structure characteristics and pore fluid division of shale oil reservoirs

作　　者：王继超 崔鹏兴 刘双双 石彬[1] 党海龙 黄兴[2] WANG Jichao;CUI Pengxing;LIU Shuangshuang;SHI Bin;DANG Hailong;HUANG Xing(Shaanxi Yanchang Petroleum(Group)Co.,Ltd.,Xi’an City,Shaanxi Province,710075,China;College of Petroleum Engineering,Xi’an Shiyou University,Xi’an City,Shaanxi Province,710065,China)

机构地区：[1]陕西延长石油(集团)有限责任公司,陕西西安710075 [2]西安石油大学石油工程学院,陕西西安710065

出　　处：《油气地质与采收率》2023年第4期46-54,共9页Petroleum Geology and Recovery Efficiency

基　　金：国家自然科学基金项目“页岩油藏超临界CO_(2)吞吐对微观孔隙结构及吸附特征作用机制研究”(52004221);“西部长6油藏水平井补充能量开发先导试验研究”(ycsy2020jcky-B-04)。

摘　　要：页岩复杂的孔隙结构导致多样化的孔隙流体类型。针对鄂尔多斯盆地延长组长7段页岩,采用低场核磁共振实验技术,将离心实验与热处理实验相结合,识别划分出3类页岩中多类孔隙流体的T_(2)弛豫时间界限,并定量表征了目标页岩的全孔径分布特征。研究结果表明,目标页岩孔隙结构可划分为Ⅰ,Ⅱ和Ⅲ类,其对应的平均孔隙半径和流体赋存量依次减小。Ⅰ,Ⅱ和Ⅲ类页岩的可动流体截止值分别为1.10,1.24和1.92 ms,不可采出流体截止值分别为0.20,0.30和0.54 ms。Ⅰ类页岩的可动流体赋存于孔径大于24.8 nm的中、大孔隙,平均饱和度为30.5%;不可采出流体则赋存于孔径小于4.5 nm的微孔隙,平均饱和度为35.3%。Ⅱ类页岩的可动流体赋存于孔径大于41.9 nm的大孔隙,平均饱和度为26.6%;不可采出流体赋存于孔径小于10.3 nm的微、小孔隙,平均饱和度为40.7%。Ⅲ类页岩的可动流体赋存于孔径大于93.6 nm的大孔隙,平均饱和度为17.2%;不可采出流体则赋存于孔径小于26.3 nm的中、小孔隙,平均饱和度达50.1%。The complex pore structures of shales lead to a variety of pore fluid types.Taking the shales of Chang 7 Member of Yanchang Formation in Ordos Basin as the research object,the low-field nuclear magnetic resonance(NMR)technology was adopted,and the T_(2) relaxation time limits of multiple types of pore fluid in three types of shales were identified by combining centrifugal test with heat treatment test.The full pore size distribution characteristics of the target shales were quantitatively characterized.The results show that the pore structures of the target shals can be divided into three types:Ⅰ,Ⅱ,andⅢ,and their corresponding average pore radii and fluid accumulations decrease successively.The cutoff values of movable fluid in the three types of shale are 1.1,1.24,and 1.92 ms,respectively,while those of non-recoverable fluid are 0.2,0.3,and 0.54 ms,respectively.The movable fluid in typeⅠshale occurs in medium and large pores with a diameter of larger than 24.8 nm,and the average saturation is 30.5%;the non-recoverable fluid occurs in micropores with a diameter of less than 4.5 nm,and the average saturation is 35.3%.The movable fluid in typeⅡshale occurs in large pores with a diameter of larger than 41.9 nm,and the average saturation is 26.6%;the non-recoverable fluid occurs in micro and small pores with a diameter of less than 10.3 nm,and the average saturation is 40.7%.The movable fluid in typeⅢshale occurs in large pores with a diameter of larger than 93.6 nm,and the average saturation is 17.2%;the non-recoverable fluid occurs in medium and small pores with a diameter of less than 26.3 nm,and the average saturation reaches 50.1%.

关 键 词：页岩 孔隙结构 核磁共振 流体类型 饱和度 

分 类 号：TE122.2[石油与天然气工程—油气勘探]