Oil-bearing evaluation of different lithofacies in Da’anzhai Member, Central Sichuan Basin: implications for shale oil development

Abstract

The Jurassic Da’anzhai Member of the Sichuan Basin has good prospects in shale oil exploration and development. However, the lack of research on the relationship between different lithofacies and oil-bearing property restricts the research on the geological theory and further exploration and development of shale oil in Da’anzhai Member. Based on core, fluorescence thin sections, rock pyrolysis, total organic carbon (TOC), extraction of chloroform bitumen ‘A’, and nuclear magnetic resonance (NMR) tests, the oil-bearing characteristics and reservoir physical properties in different lithofacies of Da’anzhai Member were analyzed. The results suggest that the oil-bearing and physical properties of shale are better than shell limestone and their peperite. The crude oil discharge from thick shale is limited because of the petrophysical property difference. The Da2b layer thick shale has the best shale oil exploration and development potential, which is the focus of the next step.