Structural evolution of the Huangling uplift, South China: Implications for the shale gas exploration in the middle and lower Yangtze River area

Abstract

Significant discoveries and breakthroughs have been made in the shale gas exploration in the southern slope zone of the Huangling uplift, periphery of the Sichuan basin. Based on previous research results, regional geological data, geophysical data and drilling data, it is proposed that the uplift has experienced four structural evolution stages since the Proterozoic, including the formation of crystalline basement in the pre-Sinian period, the intrusion of rock mass in the early Sinian period, the alternation of subsidence, deposition, uplift and denudation in the Sinian-middle Jurassic period, and the rapid uplift in the late Jurassic-Paleogene period. This distinctive structural evolution history of the Huangling uplift plays an important role in the shale gas accumulation, in which the third stage assures the appropriate depth and moderate thermal evolution and porosity, and the strong basement formed in the first stage protects the relative integrity and continuity of the sedimentary cap. We also found some uplifts with similar structural evolution history, basement and cap features as the Huangling uplift in the middle and lower Yangtze River area, such as the Xuefeng uplift and Qianzhong uplift on the periphery of the Sichuan Basin, and the Huoqiu uplift in the southern North China Basin. Through further geological, geophysical and drilling work, oil/gas reservoir may be discovered in the above uplifts.

Keywords

• paleo-uplift
• shale gas reservoir
• structural evolution
• middle and lower yangtze river area
• implications for exploration