Gas Reservior Forming Characteristics and Significance of the Middle-Upper Cambrian Xixiangchi Group in Eastern Chongqing area
A major gas exploration breakthrough was made in the Xixiangchi group through Well Pingqiao 1 which located in Pingqiao area,south of eastern Chongqing.Based on the study of carbon isotope of natural gas,it is considered that the hydrocarbons in Xixiangchi group reservoir come from Wufeng-Longmaxi for-mation source rocks.A preliminary study on the reservoir through core,logging of Well Pingqiao 1,com-bined with Xixiangchi Group section from nearby Sanquan of Nanchuan and etc reveals that the vug of Xixi-angchi group are developed,and the gas reservoir belongs to vuggy reservoir or fracture-vuggy reservoir.Based on study of the sequence of filling minerals such as dolomite,quartz,calcite and etc.and mineral inclu-sion characteristics of fractures of core from Well Pingqiao 1,the results show that the fracture formation and mineral filling mainly occurred in Yanshan-Himalayan period,the Yanshan tectonic deformation period is an important period for hydrocarbon charging in Xixiangchi group,and the Yanshan-Himalayan uplift period is also a period for further hydrocarbon charging.The successfully exploration of Xixiangchi Group in Pingqiao area,south of eastern Chongqing proves that partial shale gas release and the lateral hydrocarbon supply of early shale gas can form industrial gas reservoirs,which is of great significance to hydrocarbon exploration of the lower assemlage of the whole high-steep structural belt in Eastern Chongqing.
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维普
