川南地区五峰-龙马溪组页岩储层微观储集空间特征

The Microscopic Reservoir Characterization of Wufeng-Longmaxi Shales in the Southern Sichuan Basin

为了探究四川盆地南部五峰-龙马溪组页岩气产层段微观储集空间,运用X射线衍射技术(XRD)、氩离子抛光-扫描电镜和低压氮气吸附-脱附等实验方法,发现川南页岩储层中脆性矿物以石英和碳酸盐为主,主要发育有机质孔、粒间孔、微裂缝和粒内孔四种类型孔隙。结果表明该地区页岩储层主要沉积于钙质半深水-深水陆棚相,有利于后期水力压裂改造;产层段孔隙类型主要以有机质孔和粒间孔为主,伴随少量的微裂缝和粒内孔。页岩吸附曲线以H2和H3型为主,主要以墨水瓶型和狭缝型孔隙为主,具有较高的比表面积和孔体积,孔隙直径主要集中在微孔和介孔区域。基于以上研究,综合对比分析了川南地区与焦石坝地区优质页岩储层。

The XRD,argon ion polishing-SEM,nitrogen adsorption/desorption and other experiments were conducted on the shale samples from the Southern Sichuan Basin to analyze their reservoir characterization.The shale samples mainly contain quartz and carbonate minerals,and develop OM(organic matter)pores,interparticle pores,microfractures and intraparticle pores.The results demonstrate that the shale reservoir was deposited in the half deep-deep with calcareous environment which is favorable for its stimulation.The producing shale member is dominated by OM pores and interparticle pores,some microfractures and intraparticle pores are also observed in them.The main curves of shale samples adsorption are type II and type III,which suggests pores in shales are ink-like pores and slat-like pores.Both of them contains great BET and BJH.The pores diameter is in range of microporous and mesoporous.Comparisons of the Southern Sichuan shale gas field and Jiaoshiba shale gas field have been conducted in detail based on former research.