Discussion on the Formation Mechanism of Siliceous Cement in the Sandstone of Xihu Sag East China Sea

The siliceous cement is widespread in the lithic sandstone and arkose of the deep reservoir of Paleogene Huagang and Pinghu Formations in Xihu Sag, East China Sea. The silicon comes from the dissolution of feldspar and debris, clay conversion and corrosion in alkaline environment. The acidic corrosion environment is most favorable to the growth of secondary quartz,and the tectonic activities also have an impact on it. The study shows that the growth mechanism of authigenic quartz dynamically responses to the physical and chemistry condition of diagenesis environment, and also indicates the geological factors such as compositional maturity, fluid potential, hydrocarbon generation window of source rock and clay dehydration. Therefore, the development of siliceous cement not only affects the physical property of reservoir, reflects the influence of diagenetic event, but also records the signifcant information of geological movement occurred during the long burial process. It is of great importance in deepening the acknowledge of hydrocarbon accumulation.