不同岩性气藏注CO_(2)渗流机理  

Seepage Mechanism of CO_(2)Injection in Different Lithological Gas Reservoirs

作　　者：张钰祥 闫海军 位云生[1,2] 曹正林 郭建林[1,2] 罗瑜 叶礼友[1,2] 钟俊杰 ZHANG Yuxiang;YAN Haijun;WEI Yunsheng;CAO Zhenglin;GUO Jianlin;LUO Yu;YE Liyou;ZHONG Junjie(State Key Laboratory of Enhanced Oil&Gas Recovery,Beijing 100083,China;Research Institute of Petroleum Exploration&Development,PetroChina,Beijing 100083,China;Exploration and Development Research Institute of PetroChina Southwest Oil&Gasfield Company,Chengdu 610041,China;School of Petroleum Engineering,China University of Petroleum,Qingdao266555,China)

机构地区：[1]提高油气采收率全国重点实验室,北京100083 [2]中国石油勘探开发研究院,北京100083 [3]中国石油西南油气田分公司勘探开发研究院,成都610041 [4]中国石油大学(华东),青岛266555

出　　处：《华南师范大学学报(自然科学版)》2025年第1期60-69,共10页Journal of South China Normal University(Natural Science Edition)

基　　金：中国石油天然气集团公司科技项目(2023YQX10501,2023YQX10503ZK);中国石油集团公司前瞻性基础性技术攻关项目(2024DJ86)。

摘　　要：气藏中注入CO_(2)提高采收率技术即CCUS-EGR有望成为支撑“双碳”目标的主体技术。针对常规气藏及致密气藏中注CO_(2)提高采收率的机理尚不清晰的问题,设计不同温压下岩样渗流能力实验,判断不同相态下CO_(2)渗流能力;建立微观数值模拟,对比孔隙空间中注入不同介质驱替CH_(4)的提采效果、波及系数和驱替效率;对含束缚水状态不同岩性样品进行CO_(2)-水-岩反应实验,结合核磁共振设备评价注入CO_(2)前后气藏渗流能力和孔隙结构的变化。结果表明:超临界CO_(2)的黏度接近气态、密度接近液态,具有极高的渗流能力;与N_(2)和H_(2)O相比,CO_(2)扩散系数最高,CO_(2)对孔隙角隅处CH_(4)的微观波及系数最高、驱替效果最好,对应的CH_(4)采收率最高;CO_(2)-水-岩反应导致碳酸盐岩、致密砂岩和火山岩样品致密化以及束缚水含量降低,其中碳酸盐岩样品反应最强烈、反应后大孔体积占比增加,而致密砂岩和火山岩样品反应后大孔体积占比减少,最终含束缚水岩样渗透率由矿物沉淀程度以及束缚水饱和度降低程度共同决定。该研究为现场常规气藏及致密气藏注入CO_(2)先导试验提供了理论支撑,并为实际应用提供了重要参考。Injecting CO_(2)into gas reservoirs to enhance gas recovery,known as CCUS-EGR(Carbon Capture,Utilization,and Storage for Enhanced Gas Recovery)technology,is poised to become the key technology supporting the strategic goals of the“dual carbon”target.To address the unclear mechanism of CO_(2)injection for enhancing gas recovery in conventional and tight gas reservoirs,experiments about the permeability of rock samples under different temperatures and pressures were conducted to determine the CO_(2)permeability across different phase states.Micro-scale numerical simulations were employed to compare the extraction efficiency,sweep efficiency,and displacement efficiency of CH_(4) when injected with different media in pore spaces.Additionally,CO_(2)-water-rock reaction experiments were performed on samples of various rock types containing bound water,with changes in permeability and pore structure of gas reservoirs before and after CO_(2)injection assessed using NMR(nuclear magnetic resonance)equipment.The research results reveal that supercritical CO_(2)exhibits viscosity similar to gas and density close to liquid,along with exceptionally high permeability.Compared to N_(2) and H_(2)O,CO_(2)demonstrates the highest diffusion coefficient,the greatest micro-scale sweep efficiency for CH_(4) in pore corners,the most effective displacement performance,and consequently,the highest CH_(4) recovery rate.The CO_(2)-water-rock reaction results in the densification of carbonate rocks,tight sandstones,and volcanic rock samples,accompanied by a reduction in bound water content.Among these,carbonate rock samples exhibit the most intense reaction,with an increase in macropore vo-lume proportion post-reaction,whereas tight sandstone and volcanic rock samples show a decrease in macropore volume proportion.Ultimately,the permeability of bound water-containing rock samples is governed by the extent of mineral precipitation and the reduction in bound water saturation.This study provides theoretical support for the pilot test of CO_

关 键 词：CCUS-EGR 渗流机理 CO_(2)-水-岩反应 扩散 孔隙结构 

分 类 号：TE311[石油与天然气工程—油气田开发工程]