下寺湾地区延长组长7陆相页岩气储层敏感性实验

利用X射线衍射、场发射扫描电镜、氮气吸附、岩心驱替实验等技术方法对鄂尔多斯盆地下寺湾地区延长组长7陆相页岩气储层进行了敏感性实验研究。结果表明,储层具中等偏弱或弱的盐敏、水敏和碱敏,弱-无酸敏,中等偏强或强的应力敏感特征,矿物组分、储层物性及储层微孔结构是影响储层敏感性的主要因素。考虑到页岩储层的特殊性,在敏感性实验中对部分关键实验技术的条件和方法进行了改进:①将压汞法毛管压力曲线与氮气吸附法BJH函数孔径分布曲线资料结合,拼接出完整的孔喉分布曲线图;②敏感性实验的样品除油采用常规洗油与高温(150~200℃)烘烤方法结合;③采用了目前最适合页岩气储层敏感性实验的脉冲气体渗透率仪,用气体驱替法代替常规液相驱替法,获取敏感性实验前后的渗透率值。通过一系列改进后的敏感性实验,取得了符合泥页岩储层特性的敏感性数据,达到了本次实验的目的和要求。 

Continental Shale Gas Reservoir Sensitivity Experimental Research of Chang 7 of Yanchang Formation in Xiasiwan Area

An experimental study has been conducted on sensitivity of the continental shale gas reservoir of Chang 7of Yanchang Formation in Xiasiwan area,using X-ray diffraction,field emission scanning electron microscope,nitrogen adsorption and core displacement experiment.The results show that the reservoir is characterized by medium weak or weaker salt sensitivity,water sensitivity and alkali sensitivity,weak-no acid sensitivity and medium to strong or strong stress sensitivity.The main factors affecting the reservoir sensitivity are the mineral components,reservoir property and reservoir pore structure.Due to the particularity of shale reservoir,some key experimental technologies and methods were improved in the sensitivity experiments.①The complete pore throat size distribution curve was formed by combining the mercury injection capillary pressure curve with the nitrogen adsorption method to obtain BJH pore size distribution curve function.②The sample oil removal in the sensitivity experiments was implemented by conventional washing oil and high temperature(150-200℃)baking method.③The pulse gas permeability tester was adopted,which is most suitable for shale gas reservoir sensitivity experiments at present.The permeability values before and after the sensitivity experiment were obtained,using the gas displacement method instead of the conventional liquid displacement method.The sensitivity of the reservoir characteristics data of the shale was obtained by the improved sensitivity experiment,which satisfies the purpose and requirements of this experiment.