Shale-gas play risk of the lower Cambrian on the Yangtze platform, South China

Abstract

This paper describes the establishment of shale-gas play risk workflow and discusses the major geologic risks for the lower Cambrian shale-gas play on the Yangtze platform. The shale-gas play risk is assessed by considering the probability of occurrence (Po) of hydrocarbon charge, reservoir, and retention (HCRR) of a shale-gas play. The Po of each of these three factors is determined according to geological understanding and data availability. The risk of these factors is categorized into high risk (Po ≤ 0.3), relatively high risk (0.3 3.5%) and poor hydrocarbon retention are the key geologic risks of the lower Cambrian shale-gas play. Uncertainty is inherent in the play risk assessment owing to sparse well data coverage. Understanding the play risks and uncertainties warrants further study of the impact of extremely high thermal maturities and burial history and how it facilitates decision-making for exploration investment.