摘要
Great heterogeneity and complex gas-water distribution have severely restricted the highly efficient development of gas reservoirs in the 2nd member of the upper Triassic Xujiahe Formation,Xinchang Gas Field,Sichuan Basin.Beyond that,the early basic geological studies did not discover the real quality reservoirs and the gas-water distribution law.In view of this,based on the previous research results,this paper first made a deep study in stages of gas reservoir-forming regularity,then explored the root cause of heterogeneity of reservoirs and the complex gas-water distribution,and finally disclosed the main controlling factors of gas accumulation and high gas deliverability and the potential targets of gas reservoir development.The following findings were obtained in this study area.a.The gas pooling was motivated by high pressure at the essential later period.The later-period fracture system,which was broken but not in fragment,and which resulted from the superposition of early paleostructures,is the main controlling factor of gas accumulation and high gas deliverability driven by high pressure.b.The heterogeneity of reservoir components leads to the complexity of diagenesis in the later-period of gas pooling;the superposition of heterogeneous reservoirs after multi-stage tectonic movements results in the present complexity of reservoirs and gas-water distribution.Field application has further validated the reliability of the above findings,providing the prospective targets for effective development of gas reservoirs in this study area.This study provides a reference to the development of similar gas reservoirs in China.