The Jinan Sag is a newly discovered oil-bearing depression in the eastern Junggar Basin,and the second member of the Permian Jingjingzigou Formation is the most important oil-bearing system in this area.Based on the conventional analysis of cores,conventional sheets,cast sheets,scanning electron microscopy and X-ray diffraction analysis of clay minerals from multiple wells,the rock and mineral characteristics,reservoir physical properties,pore characteristics and main factors affecting reservoir physical properties of sandstone reservoirs in the second member of the Permian Jingjingzigou Formation were systematically studied.The results show that the sandstone reservoir of the second member of the Jingjingzigou Formation has low mineral maturity and medium structural maturity,and belongs to the characteristics of tight reservoirs of low-ultra-low porosity,extra-low-ultra-low permeability,nanoscale pore-throat and in the middle diagenetic A stage.On this basis,in-depth analysis through qualitative,semi-quantitative,it is clarified that compaction and cementation,especially early carbonate cementation,are the main controlling factors leading to the formation of tight reservoirs in this area.Besides,the dissolution in the middle diagenetic effectively improved the reservoir physical properties.The calculations show that the original porosity of the sandstone reservoir of the second member of the Permian Jingjingzigou Formation in Jinan Sag was about 27.1％on average.The average porosity lost by compaction and cementation is about 11.3％and 9.8％,and the porosity resulting from dissolution averages about 3.4％.
关键词
准噶尔盆地东部吉南凹陷/二叠系井井子沟组二段/储层岩矿特征/储层物性特征/储层物性影响因素
Key words
Jinan Sag in the eastern Junggar Basin/Second member of the Permian Jingjingzigou Formation/Reservoir rock and mineral characteristics/Reservoir physical characteristics/The controlling factor of reservoir properties
维普
万方数据