Study On Oil Shale Reservoir Characteristics Of Qingshankou Formation In The South Of Sanzhao Sag,Songliao Basin

Qingshankou Formation in the Songliao Basin is one of the main strata of domestic shale oil exploration.The research on the characteristics of shale oil reservoir of the Songliao the basin is of great significance.At the same time,shale oil is also an important replacement resource for Daqing Oilfield to maintain stable oil and gas production after the exploration and development of conventional oil and gas resources.Sanzhao sag is an important area for shale oil exploration and development in the basin.The Sanzhao sag is characterized by complex sedimentary environment andstrong reservoir heterogeneity.However,there is a lack of systematic research on the lithology,reservoir type and micro pore structure of mud shale series of Qingshankou Formation in Sanzhao sag.By sorting out the relevant geological data and rock samples in the study area,this paper systematically carries out various experiments on shale oil reservoir and micro pore research,demonstateds the characteristics of shale oil reservoir and micro pore structure of Qingshankou Formation in the Sanzhao sag,and discussed the controlling factors of reservoir development.The results show that the shale series of Qingshankou Formation in Sanzhao sag mainly developed semi-deep lake to deep lake facies.The mineral type are mainly clay minerals and mainly develops laminar structure.The physical properties of the reservoir are poor,the porosity is between 2.83 ～ 17.98%,and the permeability is generally lower than 1m D.According to the mineral composition and organic matter content of the reservoir,the reservoir in the study area is divided into clay shale type,laminar shale type and interlayer type.Micro pore types are mainly divided into three categories: micro fracture,inorganic mineral pore and organic pore.Many micropores and mesopores are developed,and macropores are less developed.The pore types and pore structure characteristics of different types of reservoirs are quite different.The reservoir development in the study area was controlled by sedimentary environment and diagenesis.The sedimentary environment affects the development of reservoir by controlling lithofacies type,rock structure,reservoir mineral composition and organic matter content in sediments.Diagenesis,including dissolution,compaction,and clay mineral transformation,has a certain impact on the development of reservoir pores.