Improved TOC prediction method for shale reservoir of Wufeng Formation and the Lower part of Longmaxi Formation in Jiaoshiba Area, Sichuan Basin

Abstract

Abstract The total organic carbon (TOC) content is the core index of shale gas reservoir evaluation. It is of great significance to quickly and accurately obtain a large number of TOC values for shale gas reservoir evaluation and sweet spots identification. The Lower Paleozoic shale gas reservoirs in southern China were once buried to a depth of more than 6000m, and the diagenesis was relatively complete. The application of various TOC estimation methods was not satisfactory so far. This paper takes the shale of Wufeng Formation and the Lower part of Longmaxi Formation in Jiaoshiba area of Sichuan Basin as the key research object. Based on the analysis and summary of well logging results, a method to improve the accuracy of TOC prediction is proposed. The improved ΔLogR technology with the participation of natural gamma-ray and bulk density logs has strong applicability, leading to accurate calculated TOC content, which has important guiding significance for exploration and development.