Diagenetic evolution and facies of reservoirs in Member 8 of Permian Xiashihezi Formation in the Z30 block of Sulige gasfield
Abtraet:Based on microscopic observations,fluid inclusions and thermodynamic analyses of various diagenetic reactions in acidic and alkaline fluid media,and combined with evolutionary history of organic matter and burial history,diagenetic evolution and facies of reservoirs in Member 8 of Xiashihezi Formation in the Z30 block of Sulige Gasfield were classified.The result showed that the Member 8 of Xiashihezi Formation reservoirs experienced at least four evolutionary stages of diagenesis,namely the syndiagenetic to early Period A of Early Diagenesis weak-acid corrosion stage,the late Period A to Period B of Early Diagenesis acid corrosion stage,the Period A to early Period B of Middle Diagenesis acid dissolution stage,and finally the late Period B of Middle Diagenesis to epigenetic alkaline metasomatism and cementation stage.The epigenetic stage emerged during the uplift of the study area.After the diagenetic evolution,five types of diagenetic facies were formed in this area,i.e,unstable component dissolution-chlorite film facies of arenite,unstable component dissolution-kaolinite and siliceous cementation facies of arenite,kaolinite and siliceous cementation-unstable component dissolution facies of arenite,unstable component dissolutioncarbonate dense cementation facies of arenite,and miscellaneous matrix-filled dense compaction facies of greywacke.The acid dissolution stage is a critical period for the formation of main reservoir space,which makes the unstable component dissolution-chlorite film facies of arenite,the unstable component dissolution-kaolinite and siliceous cementation facies of arenite and the kaolinite and siliceous cementation-unstable component dissolution facies of arenite as the constructive diagentic facies of reservoirs.
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万方数据
维普
