Shale gas resource evaluation based on "pressure coefficient": a case study of Upper Ordovician Wufeng-Lower Silurian Longmaxi formations in southeastern Sichuan Basin

Abstract

With the continuing shale gas exploration and development in China, it is necessary to establish a scientific method to evaluate shale gas resources. This paper focuses on considering the heterogeneity of shale gas resource distribution and the impact of preservation conditions. On the basis of identifying the main influencing factors of shale gas "pressure coefficient", the study area is divided into A-type area (pressure coefficient >1.2), B-type area (pressure coefficient 1.0-1.2) and C-type area (pressure coefficient 0.8-1.0). By dissecting the shale gas calibrated area of Upper Ordovician Wufeng-Lower Silurian Longmaxi formations in Fuling, the resource volume is obtained as a key parameter for analog calculation, and the shale gas resources are evaluated by analogy. Comprehensive calculation of the total shale gas resources in the southeastern Sichuan area is 5.52×1012 m3, 4.04×1012 m3 of which is accounted for between 4 500-6 000 m depth, indicating that shale gas with a burial depth greater than 4 500 m in this area has a greater shale gas exploration potential.

Keywords

• pressure coefficient
• resource evaluation
• shale gas
• wufeng-longmaxi formations
• sichuan basin