CO_2-地层水-岩石相互作用对特低渗透砂岩孔喉伤害程度定量评价  

Quantitative Study on the Damage Degree of CO_2-Formation Water-Rock Interaction on Pore and Throat of Ultra-low Permeability Sandstone

作　　者：王琛[1,2] 李天太[1] 高辉[1] 赵金省[1] 高媛[3] WANG Chen;LI Tiantai;GAO Hui;ZHAO Jinsheng;GAO Yuan(College of Petroleum Engineering,Xi'an Shiyou University,Xi’an 710065,Shaanxi,China;Faculty of Petroleum Engineering,China University of Petroleum (Beijing),Beijing 102249,China;Shaanxi Gas Group Co.,Ltd.,Xi’an 710016,Shaanxi,China)

机构地区：[1]西安石油大学石油工程学院,陕西西安710065 [2]中国石油大学(北京)石油工程学院,北京102249 [3]陕西燃气集团有限公司,陕西西安710016

出　　处：《西安石油大学学报（自然科学版）》2017年第6期66-72,共7页Journal of Xi’an Shiyou University（Natural Science Edition）

基　　金：国家自然科学基金项目(51774236);中国石油科技创新基金项目(2017D-5007-0104)

摘　　要：为明确CO_2驱过程中CO_2-地层水-岩石的相互作用对特低渗透砂岩不同尺度孔喉的伤害情况,利用核磁共振技术定量计算驱替后砂岩岩心的孔喉堵塞程度。研究结果表明,实验后产出液的pH值低于实验前的地层水,且离子浓度的变化反映长石和碳酸盐矿物发生了溶解;在驱替时间为60 h,T2值在0.1~10.0 ms内的较小孔喉有11.21%~13.25%被堵塞;反应时间为120 h,较小孔喉平均堵塞程度达到25.25%;而T2值在10.0~1 000.0 ms内的较大孔喉始终未发生明显堵塞。CO_2与矿物的溶解反应对岩心渗透率的伤害明显高于对孔隙度的伤害,且伤害程度与反应时间呈正相关,与CO_2注入压力无明显相关性。In order to clarify the damage degree of CO2-formation waterrock interactionon on pore throats in ultralow permeability sandstone,the plugging degree of pore throats after CO2flooding were quantitatively analyzed by nuclear magnetic resonance(NMR).The results show that the pH value of the formation water after the experiment is lower than that before the experiment,the change of the ion concentration after CO2flooding reflects the dissolution of feldspar and carbonate minerals;when the interaction time is60h,the small pore throat of11.21%~13.25%whoseT2is0.1~10.0ms was plugged;when reaction time is120h,the blockage ratio of the small pore throat is more than25.25%,but the large pore throat whoseT2is10.0~1000.0ms was not significantly blocked;the damage caused by the dissolution action of CO2on minerals on the core permeability is significantly higher than that on the core porosity,and the damage degree is positively correlated with the reaction time,and had no significant correlation with the CO2injection pressure.

关 键 词：CO2驱 特低渗透砂岩 CO2、水、岩间的作用 孔喉堵塞率 定量评价 

分 类 号：TE122.23[石油与天然气工程—油气勘探]