徐家围子断陷沙河子组致密储层孔径分布定量表征  

Quantificational characterization of tight reservoir pore size distribution of Shahezi Formation in Xujiaweizi Fault Depression

作　　者：郭思祺 肖佃师[1,2] 卢双舫 张鲁川 谷美维 

机构地区：[1]中国石油大学(华东)非常规油气与新能源研究院,山东青岛266580 [2]成都理工大学油气藏地质与开发工程国家重点实验室,四川成都610059

出　　处：《中南大学学报（自然科学版）》2016年第11期3742-3751,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学重点基金资助项目(41330133);国家重点基础研究发展计划(973计划)项目(2014CB239005-001);山东省优秀中青年科学家科研奖励基金资助项目(2014BSE28018);中国石化科技攻关项目(P15028);高校自主创新科研计划项目(15CX05046A;15CX07004A)~~

摘　　要：以徐家围子断陷沙河子组致密砂砾岩储层为例，联合低温氮气吸附和高压压汞资料标定核磁共振T2谱，实现核磁弛豫时间T2向孔喉半径rc的转换；结合核磁孔径分布曲线和铸体薄片资料，定量评价沙河子组致密储层的微观孔径分布及其影响因素。研究结果表明：核磁孔径分布曲线与低温氮气吸附及压汞的孔径分布曲线基本吻合，弥补前人标定核磁弛豫时间时较小、孔径部分精度较差的不足。沙河子组致密砂砾岩储层孔径主要分布区间为0.01~10μm，分布曲线多表现为双峰状。孔径主要受压实作用、胶结作用及溶蚀作用影响。随着压实作用的增强，孔隙及喉道变小；胶结物含量的增加进一步降低孔喉连通性；溶蚀作用是致密储层大孔发育的主要因素。Taking tight glutenite reservoir of Shehezi Formation in Xujiaweizi Fault Depression as an example, conversions from nuclear magnetic resonance （NMR） T2 to pore throat radius （rc） were realized by cryogenic nitrogen adsorption experiment and mercury injection to calibrate NMR T2, then microscopic pore size distribution and its influence factors were quantitatively evaluated by NMR pore size distribution curves and casting thin sections. The results show that NMR pore size distribution curves are similar to those of nitrogen adsorption and of mercury injection, which remedy the shortages of previous studies that smaller pore sizes have low precision. The main pore sizes of tight glutenite reservoirs of Shahezi Formation range from 0.01 to 10μm. Distribution curves are always bimodal. Pore size is mainly affected by compaction, cementation and dissolution. With enhanced compaction, pores and throats become smaller. Increasing cement content reduces connection further, while dissolution is the major factor that tight reservoirs develop megalopores.

关 键 词：致密储层 低温氮气吸附 核磁共振 压汞技术 孔径分布 

分 类 号：P618.13[天文地球—矿床学]