CO_2-水-岩石相互作用对岩石孔渗参数及孔隙结构的影响——以延长油田35-3井储层为例  

Effect of CO_2-water-rock Interaction on Porosity,Permeability and Pore Structure Characters of Reservoir Rock:A Case Study of 35-3 Well in Yanchang Oilfield

作　　者：肖娜 李实[2] 林梅钦[3] XIAO Na;LI Shi;LIN Meiqin(Province Key Laboratory of Drilling and Production Engineering for Oil and Gas, College of Petroleum Engineering, Yangtze University, Wuhan, Hubei 430100, P R of China;Research Institute of Petroleum Exploration and Development, Beijing 100083, P R of China;Enhanced Oil Recovery Research Center, China University of Petroleum, Beijing 102249, P R of China)

机构地区：[1]长江大学石油工程学院油气钻采工程湖北省重点实验室,湖北武汉430100 [2]中国石油勘探开发研究院,北京100083 [3]中国石油大学(北京)提高采收率研究院,北京102249

出　　处：《油田化学》2018年第1期85-90,共6页Oilfield Chemistry

基　　金：中国石油科技创新基金项目"低渗透裂缝性油藏CO2驱提高采收率技术的基础研究"(项目编号2015D-5006-0206)

摘　　要：二氧化碳注入油藏后会与储层中的地层水和岩石发生反应,导致储层的孔隙度、渗透率和孔隙结构等物性参数发生改变。以延长靖边油田特低渗油藏35-3井储层岩心为研究对象,研究了不同反应时间和反应压力下CO_2-水-岩石相互作用后,岩石孔隙度、渗透率和孔隙结构分布的变化,考察了压力对CO_2-水-岩石相互作用后岩石表观形貌及溶液中Ca^(2+)浓度的影响。结果表明,岩石孔隙结构的变化受溶蚀作用、微粒运移和新生矿物沉积的综合影响;当反应时间和反应压力改变时,岩石内小孔隙的分布发生较大的改变,大孔隙分布变化不明显。CO_2-水-岩石作用6数24 h后,岩石水测渗透率均降低;随反应时间增加,岩石孔隙度先降低后增加,岩石渗透率恢复值逐渐增加,CO_2对储层渗透率变化的影响逐渐减小。CO_2-水-岩石在7数15 MPa下作用后,岩石水测渗透率均降低;随压力增加,岩石孔隙度先增加后降低,岩石渗透率恢复值逐渐降低,CO_2对储层渗透率变化的影响增加。反应压力增加,岩石溶蚀现象更加明显,溶液中Ca^(2+)浓度增加。CO2 could react with formation water and reservoir rock when it was injected into reservoir. The interaction of CO2-rock-water could change the porosity,permeability and pore structure characters of the reservoir. In this paper,the changes of porosity,permeability and pore structure of the rock were measured after rock reacted with CO2 and water in different reaction times and under different reaction pressures. The apparent morphology of the rock and Ca^（2＋） concentration in water after the interaction of CO2-rock-water under different pressures were also measured. The results showed that the change in pore structure of rock was influenced by the comprehensive effects of dissolution,particle migration and the deposition of new minerals. With the change of reaction time and reaction pressure,the distribution of small pores in rock changed greatly,while that of macropores changed little.The water permeability of rocks all decreased after CO2-water-rock reaction of 6—24 hrs. With the increase of reaction time,the porosity of rock decreased first and then increased,the permeability recovery of rock increased gradually which showed that the effect of CO2 on reservoir permeability changes decreased gradually. The water permeability of rocks all decreased after CO2-water-rock reaction under 7—15 MPa. With the increase of reaction pressure,the porosity of rock increased first and then decreased,the permeability recovery of rock decreased gradually which showed that the effect of CO2 on reservoir permeability changes increased gradually. The dissolution of rock was more obvious and the concentration of Ca^（2＋） in solution increased with the increase of reaction pressure.

关 键 词：二氧化碳 岩石 相互作用 孔隙度 渗透率 孔隙结构 

分 类 号：TE357.45[石油与天然气工程—油气田开发工程] P584[天文地球—岩石学]