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应用偏光显微镜、环境扫描电镜、恒压压汞以及近年来发展起来的恒速压汞技术对鄂尔多斯盆地神木地区上古生界太原组和下石盒子组天然气储集层进行了研究。研究区该储层岩性以粗粒、巨—粗粒岩屑石英砂岩为主,石英砂岩、岩屑砂岩为次,由于成岩作用强烈,残余原生粒间孔基本全部丧失,而煤系地层提供的大量有机酸以及丰富的可溶性组分,使太原组形成了以溶孔为主的储集层,下石盒子组则主要以高岭石晶间微孔为主。恒速压汞的测试表明,太原组、下石盒子组储集层孔隙结构差别明显,太原组储集层孔径大、孔喉比大,而下石盒子组孔径小,孔喉比接近于1∶1,属于较差的孔喉配置。
The natural gas reservoirs of Taiyuan Formation and Xiashihezi Formation of Upper Paleozoic in Shenmu area of Ordos Basin were studied by using polarized microscope, environmental scanning electron microscope, constant pressure mercury injection and constant pressure mercury injection technique developed in recent years. The lithology in the study area is mainly coarse-grained, giant-coarse-grained lithic quartz sandstone, and quartz sandstone and lithic sandstone are secondary to this study. Because of the strong diagenesis, the residual primary intergranular pores are basically lost, whereas the coal measures provide A large number of organic acids and rich soluble components, so that the formation of the Taiyuan Formation dissolved pore-based reservoirs, the lower Shi box sub-group mainly kaolin intergranular micropores. The results of constant-rate mercury intrusion show that the pore structure of reservoirs in Taiyuan Formation and Xiashihezi Formation is obviously different. The pore size of reservoirs in Taiyuan Formation is large and the pore-to-throat ratio is large. However, the pore diameter of the lower lithosphere subgroup is small and the pore throat ratio is close to 1 : 1, belonging to the poorest pore throat configuration.