Oil & Gas Geology ›› 2011, Vol. 32 ›› Issue (1): 124-132.doi: 10.11743/ogg20110115

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Genetic pattern of lowresistivity gas reservoirs in the Xujiahe Formation, southeastern Sichuan Province

  

  • Online:2011-02-28 Published:2011-04-28

Abstract:

Gas reservoirs in the Upper Triassic Xujiahe Formation, southwestern Sichuan Province are characterized by low resistivity, complex genetic types and complex gaswater relationships, which make them hard to identify. Using data from core analysis, logging, structures, testing and logging responses, we thoroughly examine genetic pattern of low resistivity gas reservoirs in the study area from macro and microviews. According to this study, main controlling factors responsible for the development of these low resistivity gas reservoirs are: 1) muddy sandstone reservoirs with low porosity and permeability developing in the context of lowamplitude structures; 2) complex pore configurations, high water saturation, and high formation water salinity; 3) lowenergy sedimentary environment resulting in fine particles in reservoirs, high mud content, some clay minerals with conductivity and enrichment of conductive minerals in certain areas. Reservoir quality has a negative correlation with resistivity.