Pore structure and fractal characteristics of Qingshankou formation shale in Gulong depression,Songliao basin
The Qingshankou formation shale in the Gulong depression of the Songliao basin is a terrestrial pure shale-type reservoir characterized by high total organic matter,high maturity,and high clay content.In order to reveal the pore structure characteristics and heterogeneity of shale in the study area,this work employs techniques including field emission scanning electron microscopy,XRD(rock mineral analysis),nitrogen adsorption,etc.,to analyze the types of reservoir space,which insisting of micropore,nanopore,and fractures,as well as the pore structure characteristics in the study area.This work categorizes fractures of the lamellation by the property of origin,and studies the fractal characteristics of the study area by adopting the FHH model.The results show that the primary composition of clay minerals are quartz,feldspar,and clay minerals,which content beyond 35％of the Gulong shale.The lamellate fractures can be divided into long-strip like penetrating fractures,short cluster-like pointed out fractures,forked layered fractures,and organic matter-filled fractures,with short cluster-like pointed out fractures being the major type.The Gulong shale has typical fractal characteristics,with the fractal dimensions of large pores ranging from 2.528 to 2.555,small and medium-sized pores ranging from 2.791 to 2.829.The main reservoir space in the Gulong shale is the 2～50 nm mesopores,with an average pore volume accounting for 79.85％.Organic carbon content positively correlates with specific surface area,pore volume,and fractal dimension,while the average pore diameter negatively correlates with fractal dimension.The range of organic matter and clay is the dominant factor influencing the fractal structure characteristics.The study of shale pore structure and fractal characteristics is significant for evaluating shale oil and gas potential and development reserves.
Songliao basinQingshankou formationshalepore structurenitrogen adsorptionfractal features
万方数据
维普
