Nanopores of the productive and non-productive sections within the Lower Silurian Longmaxi Shale Reservoir in the Southern Area of Sichuan Basin, China

Abstract

Abstract This study focuses on nanopores of the productive and non-productive sections within the Lower Silurian Longmaxi shale reservoir in the southern area of Sichuan Basin. 4 rock samples from the productive section and 12 rock samples from the non-productive section were collected from a new exploration well in Changning Area. TOC, XRD and gas adsorption measurements were conducted on these samples. The productive section contains more organic matters, biogenic quartz, but less carbonates and feldspar and is much more porous relative to the non-productive section. Organic matters and clays have important impacts on the development of nanoporosity within the Lower Silurian Longmaxi shale reservoir in study area. Nanoporosity of the productive section is affected mainly by the organic matter contents, and hence implying the predominance of organic-matter pores within this section. Clay minerals have the primary controlling effects on the occurrence of nanopores within the non-productive section, and then indicating the predominance of mineral matrix pores in it. This study should be helpful for us to make a better understanding of in-situ shale gas resources and to optimize targets in this region.