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Uppermost Permian reefs from the Wubaiti structure in eastern Sichuan, China: implications for exploration of natural gas reservoirs

Authors


Z.-Q. Shi, Chengdu University of Technology, Chengdu, Sichuan, 610059, China. E-mail: szqcdut@163.com

Abstract

Changhsingian (latest Permian) reefs are reported from the Wubaiti structure, northern Sichuan Basin of southwest China. Here, reefs grew along the platform margins and their tempo-spatial distribution and growth stages were determined based on the integration of detailed seismic profiles, well logs and core data. The Wubaiti reefs experienced two distinct development stages. The first episode of reef development was characterized by the growth of coral and sponge patch reefs during early–middle Changhsingian time. The second episode, the main growth phase of the Wubaiti reefs, occurred in late Changhsingian time when both sponges and algae acted as major reef-builders. These reef-building organisms disappeared in the Permian–Triassic mass extinction. Reef growth coincided with a local transgression event, but ceased due to a fall in local sea-level in the latest Changhsingian time. Dolostones of various parts of the Wubaiti reefs provide considerably high-quality reservoirs for natural gas in the Sichuan Basin. Copyright © 2012 John Wiley & Sons, Ltd.

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