Study On Diagenetic Facies Of The Second Member Of Xujiahe Formation In Suining-Pengxi Area

Diagenetic Facies has a significant impact on the characteristics and distribution of the tight sandstone reservoir.Suining to Pengxi area after the early exploration,showing good exploration prospects.The petroleum geology and reservoir geology as the guide of this paper,and according to the drilling,production and well logging processing data,with the mineral casting thin section identification,image analysis and mercury analysis,granularity analysis,X-ray diffraction analysis,inclusion analysis,vitrinite reflectance analysis means to carry out the formation,sedimentary types,reservoir characteristics,diagenesis and diagenetic facies of the second member of Xujiahe Formation in Suining to Pengxi area.The results show:The second member of Xujiahe Formation which also can be divided into three sub segments.The Sandstone is formed in the beach bar of the shallow lacustrine depositional environment.The reservoir physical property is poor,mainly with the secondary dissolution pores,with a small amount of residual intergranular porosity and pore throat structure is poor,is a typical low porosity and permeability reservoirs,and the type of reservoir properties is fracture-pore type.The reservoir has experienced complex diagenetic evolution,and is currently in the middle diagenetic A-B stage.compaction and cementation greatly damage the reservoir quality,dissolution is key to improved the property of reservoir to some extent.in the study area have been classification six types of diagenetic facies,there are siliceous-chlorite cementation diagenetic facies,siliceous cementation-dissolution diagenetic facies,Cal cite cementation diagenetic facies,compaction diagenetic facies,Miscellaneous filling-ompaction diagenetic and siliceous cementation diagenetic facies,and different diagenetic facies have different of characteristics,the diagenetic coefficient has also different.siliceous-chlorite cementation diagenetic facies,siliceous cementation-dissolution diagenetic facies are the most advantage to the reservoir,and predicting of favorable diagenetic facies plane distribution based on conventional logging information.With the analysis of the favorable sedimentary facies,reservoir,diagenetic facies,and characteristics of drilling,considering the upper sub segment of the second member of Xujiahe Formation is the most favorable exploration layer,and The favorable reservoir exploration area of each sub segmen has divided by using the comprehensive analysis method.