注CO_(2)页岩孔隙结构及渗透率变化特征  

Varying Characteristics of Pore Structure and Permeability of Shale Injected CO_(2)

作　　者：习丽英[1] 黄朝[1] 米燕华 王磊[1] 孙龙[1] 曹青赟 邓宝康 XI Liying;HUANG Chao;MI Yanhua;WANG Lei;SUN Long;CAO Qingyun;DENG Baokang(No.2 Gas Production Plant,PetroChina Changqing Oilfield Company,Yulin,Shaanxi 719000,China;Sichuan OGT Oilfield Technology Development Co.,Ltd.,Chengdu,Sichuan 610041,China)

机构地区：[1]中国石油长庆油田分公司第二采气厂,陕西榆林719000 [2]四川奥吉特油田科技开发有限公司,四川成都610041

出　　处：《西安石油大学学报(自然科学版)》2025年第2期49-55,共7页Journal of Xi’an Shiyou University(Natural Science Edition)

基　　金：国家自然科学基金项目“陆相页岩油藏CO_(2)压裂复杂缝网形成机制及增产机理”(5207042143)。

摘　　要：为研究微观和宏观尺度下气态CO_(2)和超临界态CO_(2)作用对页岩孔隙结构及渗透率特征的影响,通过低温氮气吸附实验和全直径岩心驱替实验进行分析。实验结果表明,超临界CO_(2)饱和页岩后,微孔(0~10 nm)比例增大,小孔(10~100 nm)和大孔(100~1000 nm)比例降低,平均孔径减小,BET比表面积和BJH总孔体积增大,而气态CO_(2)作用效果与之相反。2种相态CO_(2)饱和页岩后的渗透率随饱和时间的增加而降低,超临界CO_(2)作用下渗透率达到稳定的饱和时间比气态CO_(2)长3 h,且渗透率降低幅度在8.4%~77.9%。随CO_(2)饱和时间的增加,压缩系数减小,渗透率应力敏感性增加,超临界CO_(2)作用下的压缩系数和渗透率应力敏感性均大于气态CO_(2)。The change characteristics of pore structure and permeability of shale after injecting gaseous CO_(2) and supercritical CO_(2) were studied at the micro and macro scales through low-temperature nitrogen adsorption experiments and full diameter core displacement experiments.The experimental results show that after saturating shale with supercritical CO_(2),the proportion of micropores(0~10 nm)increases,the proportion of small pores(10~100 nm)and large pores(100~1000 nm)decreases,the average pore size decreases,the BET specific surface area and BJH total pore volume increase.However,the results are opposite after saturating shale with gaseous CO_(2).The permeability of shale saturated with two phases of CO_(2) decreases with increase of saturation time.The time for the permeability of the shale saturated with supercritical CO_(2) to reach stability is 3 hours longer than that of gaseous CO_(2),and the decrease in permeability ranges from 8.4%to 77.9%.As the CO_(2) saturation time increases,the compression coefficient of shale decreases and the stress sensitivity of shale permeability increases.The compression coefficient and permeability stress sensitivity of the shale saturated with supercritical CO_(2) are both greater than those of the shale saturated with gaseous CO_(2).

关 键 词：孔隙结构 渗透率 超临界CO_(2) 吸附 溶胀 页岩 

分 类 号：TE349[石油与天然气工程—油气田开发工程]