致密砂岩压裂后的储层敏感性特征实验——以四川盆地JQ地区沙溪庙组8号砂体为例  

Experimental study on reservoir sensitivity characteristics of tight sandstone after fracturing:Taking No.8 sand body of Shaximiao Formation in JQ area of Sichuan Basin as an example

作　　者：汪煜昆 赵丹 刘婷芝 淦文杰 王永强[1] 张清秀 郭静姝 WANG Yukun;ZHAO Dan;LIU Tingzhi;GAN Wenjie;WANG Yongqiang;ZHANG Qingxiu;GUO Jingshu(Central Sichuan Oil and Gas District,PetroChina Southwest Oil&Gasfield Company,Suining,Sichuan 629000,China;Exploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Cheng-du,Sichuan 610041,China)

机构地区：[1]中国石油西南油气田公司川中油气矿,四川遂宁629000 [2]中国石油西南油气田公司勘探开发研究院,四川成都610041

出　　处：《天然气勘探与开发》2024年第3期85-93,共9页Natural Gas Exploration and Development

摘　　要：随着油气勘探开发向非常规领域深入,压裂等储层改造措施的应用越来越广泛。为了深入认识储层特性,了解储层潜力,预测储层改造后敏感性特征变化,从而进行合理的储层保护措施,有必要开展储层岩心模拟改造后的敏感性实验,明确储层改造措施对储层敏感性特征的影响。基于钻井获取岩心,在薄片鉴定、X射线衍射、扫描电镜分析以及压汞测试实验等手段的基础上,开展不同压力、温度、流体化学性质等条件下的流动实验,以评估储层的敏感性特征。通过对比改造前后岩心敏感性实验结果的差异,分析储层改造措施对储层敏感性特征的影响。结果表明:①模拟储层改造后中侏罗统沙溪庙组8号砂体岩心出现网状裂缝,渗透率相比改造前平均提升167%。②改造之前的JQ地区沙溪庙组岩心具有中等偏弱速敏、强水敏、弱盐敏、弱碱敏、弱酸敏的特征;改造后,速敏、盐敏等敏感性特征没有改变,而水敏由强转弱,强水敏的样品比例由93%下降到17%。③综合分析改造后敏感性特征,改造后岩心的水敏程度较改造前下降,出现弱水敏和无水敏的结果,因此需要增加储层改造措施的影响范围,以此提升储层流体流动能力。With the expansion of hydrocarbon exploration into unconventional fields,the reservoir stimulation treatments such as fracturing are increasingly applied.For purposes of understanding reservoir properties,figuring out reservoir potential,predicting the changes in reservoir sensitivity characteristics after stimulation,and then implementing appropriate reservoir protection,it is necessary to conduct sensitivity experiments on reservoir cores after simulated stimulation in order to identify how the stimulation affects the reservoir sensitivity characteristics.Through thin section identification,X-ray diffraction,scanning electron microscopy,and mercury injection test,flow experiments were carried out for drilled cores under different pressures,temperatures and fluid chemical properties to evaluate the reservoir sensitivity characteristics.The results of sensitivity experiments on cores before and after stimulation were compared to analyze the impacts of stimulation treatment on reservoir sensitivity characteristics.The results are shown as follows:(i)There appears netlike fractures in the cores drilled from No.8 sand body of the Middle Jurassic Shaximiao Formation in the JQ area of Sichuan Basin after stimulation,and the core permeability is 167% higher averagely than that before stimulation.(ii)The cores are characterized by moderate to weak velocity sensitivity,strong water sensitivity,weak salt sensitivity,weak alkali sensitivity,and weak acid sensitivity.After stimulation,the characteristics of velocity sensitivity and salt sensitivity remain unchanged,while the strong water sensitivity changes to a weak level.Moreover,the proportion of core samples with strong water sensitivity reduces to 17% from 93%.(iii)Comprehensive analysis indicates that the stimulated cores present a reduced level of water sensitivity,which manifests as weak or zero water sensitivity.Thus,the coverage of reservoir stimulation treatments needs to be expanded so as to improve the reservoir fluid flow capacity.

关 键 词：致密砂岩 渗流实验 储层改造 敏感性特征 CT扫描 

分 类 号：P618.13[天文地球—矿床学]