Control factors of compacted high quality sandstone reservoirs of member 2 of Xujiahe formation, upper Triassic in Xinchang gas field of Western Sichuan depression

Key words:  Xinchang gas field  Xujiahe formation  high quality reservoir  diagenesis  porosity

Abstract:

Based on the rock thin section analysis, the sandstone reservoirs of member 2 of Xujiahe formation, upper Triassic in Xinchang area were studied by using technologies of quantitative analysis of diagenesis and diagenetic evolution. The results show that the reservoirs have the characteristics of low porosity and low permeability in Xinchang area, but the high quality reservoirs with pore developed also exist. The high quality reservoirs developed in sandstone with high maturity and structure maturity, coarse grain size and low debris content. During the process of diagenesis, the high quality reservoirs have strong resistance to compaction. The combined effect of self quartz and chlorite reached the role of compaction resistance, which preserves more primary pore and provides beneficial filtration path. The filtration path will advantage to form post secondary dissolution pores.