基于地质、测录井和实验分析资料,运用建立的页岩气储层定量表征方法,开展了彭水地区上奥陶统五峰组—下志留统龙一段常压页岩气储层研究,认为①—⑤小层内的优质页岩储集空间以有机质孔隙、页理缝或层理缝为主。FIB（聚焦离子束）测得的算术平均孔径以中孔为主（20~50 nm）,而体积加权平均孔径为大孔（100 nm）,这表明大孔是总体积和孔隙度的主要贡献者。岩心尺度裂缝导致气测突然降低或增高和小层级别的页岩气发生迁移。Maps新方法表明：隆页1井①小层的层理缝是张开且连续的,张开宽度为4.69 μm;顺层剪切缝的张开宽度为1.1~2.67 μm,层理缝与顺层剪切缝的面孔率之和为1.39 %,约占样品总孔隙度的1/3,说明层理缝与天然构造缝是主要的页岩气储层空间。与超压页岩气藏相比,常压区页岩储层的孔隙度略低,高角度缝及层理缝更发育。根据常压页岩气的储层评价参数与标准,对武隆向斜①—⑤小层页岩段进行评价,Ⅰ类储层有利区为620.22 km²。

Based on geological, logging and experimental analysis data, normal-pressure shale gas reservoir of Upper Ordovician Wufeng Formation to Lower Silurian Longmaxi Member in Pengshui area has been researched by the established quantitative characterization method, and it is found that the reserving space of high-quality shale in ①—⑤ layers is mainly composed of organic pores and bedding joints. The arithmetic average aperture measured by FIB nanotechnology with higher resolution ranges is from 20 to 50 nm, being mainly mesopores. However, the volume weighted average aperture is 100 nm, being macropore. In terms of the measured pore volume, macropore is the main contributor to total volume and porosity. Core-scale fractures lead to the abrupt decrease or increase of gas logging and the migration of shale gas at layer-level. The new method, Maps, show that the bedding joints in layer① of well-Longye-1 are open and continuous with an opening width of 4.69 μm, and the opening width of bedding shear joint is 1.1~2.67 μm. The sum of plane porosity for bedding and bedding shear joints is 1.39 %, which accounts for about 1/3 of the total porosity of the sample. It confirms the important contribution of bedding fracture and natural tectonic fracture for shale gas reservoir spaces. Comparing with the overpressure shale gas reservoirs, the porosity of shale reservoir in normal-pressure area is slightly low, and the high-angle seam and bedding joints are more developed. A new parameters and criteria method for evaluating normal-pressure shale gas reservoirs has been established. By this method, favorable reservoir area of type I reservoir is of 620.22 km² in layer ① to ⑤ of Wulong syncline.