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Geoscience ›› 2016, Vol. 30 ›› Issue (5): 1085-1095.

• Engineering Geology and Environmental Geology • Previous Articles     Next Articles

Differential Structural Evolution and Its Influence on the Natural Gas Accumulation of Continental Strata in the Western and Northeastern Sichuan Basin

YU Dongdong1,2, TANG Liangjie1,2, YU Yixin1,2, CHEN Qian1,2   

  1. 1State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing102249, China; 2Basin and Reservoir Research Center, China University of Petroleum, Beijing102249, China
  • Online:2016-11-07 Published:2016-11-14

Abstract: The west and northeast of Sichuan Basin, located at the northwestern margin of the Yangtze Platform,both developed typical foldthrust belts and foreland basins, and shared certain similarities in relate to structural characteristics. Based on the interpretation of seismic data and anatomy of typical gas fields and in combination with previous study results, this study analyzed differential structural evolution and its influence on natural gas accumulation characteristics in the west and northeast of Sichuan Basin. Consequently, the western Sichuan Basin was mainly affected by the Longmenshan orogenic belt and the corresponding foreland basin formed from the Middle and Late Indosinian,then mainly influenced by Late Yanshanian and Himalayan tectonic movement; but the northeastern Sichuan Basin from the Early Yanshanian began to develop foreland basin, then was influenced by the combination of Dabashan, Micangshan and Xuefengshan in the Middle and Late Yanshanian, finally formed in the intensive movement of Dabashan orogenic belt in the Himalayan. Above differential structural evolution affected the hydrocarbon accumulation characteristics in the continental strata of the west and northeast of Sichuan Basin respectively, which are reflected mainly in source rocks, pathway system, preservation condition and natural gas accumulation process. The western Sichuan Basin mainly developed Xujiahe Formation source rocks, and its pathway system consisted of NE and SN trending faults and relational fractures and its large faults formed by multiperiod tectonic movements affected the preservation of gas fields in piedmont faultfold zone, experiencing four key accumulation periods, ie Late Indosinian, Middle and Late Yanshanian and Himalayan. The northeastern Sichuan Basin developed two sets of source rocks,ieXujiahe Formation and Lower Jurassic, and its NW trending faults were the main pathway system, and its erosion and large faults caused poor preservation condition of piedmont faultfold belt, experiencing three key accumulation periods, ieMiddle Yanshanian,Late Yanshanian and Himalayan.

Key words: foreland basin, differential structural evolution, control on hydrocarbon accumulation, continental stratum, western Sichuan Basin, northeastern Sichuan Basin

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