Shale Oil Reservoir Characteristics Of Funing Formation In Subei Basin And Its Influence On Oil Conten

Shale oil is a very important unconventional oil resource with great resource potential and good development prospects.Different from conventional oil resources,the enrichment mechanism of shale oil has its uniqueness.Micro nano pores in shale reservoir provide storage space for shale oil.Reservoir characteristics have a great impact on oil bearing property,which is also the key to study the enrichment mechanism of shale oil.Funing Formation shale in Subei basin is a typical continental shale.A comprehensive understanding of the basic geological characteristics of shale oil in this area and the main controlling factors of shale oil rich integrated reservoir can provide theoretical guidance for evaluating the potential of shale oil resources and implementing the scale of shale reservoir.Taking the study area as the research object,this paper makes a qualitative and quantitative analysis on the characteristics of shale reservoir and its oil-bearing property by means of rock thin section identification,XRD ray diffraction analysis of whole rock and clay minerals,field scanning electron microscope,nitrogen isothermal adsorption,high-pressure mercury injection,organic carbon content analysis,core rock pyrolysis analysis,vitrinite reflectance analysis,fluorescent thin film identification and other technical means,so as to clarify the control role of reservoir characteristics on oil-bearing property.The shale of Funing Formation in Subei Basin mainly develops horizontal bedding,and the alternating distribution of bright and dark stripes forms a layer pair combination.The bright stripes are mainly carbonate minerals,and the dark stripes are mainly silicate minerals and clay minerals.The mineral composition is mainly quartz,calcite and clay minerals,and the content difference of the three main minerals is small.It mainly develops four lithofacies:Organic poor siliceous shale,organic rich siliceous shale,organic rich mixed shale and organic calcareous shale.The shale reservoir of Funing Formation in Subei basin develops many types of reservoir spaces,such as organic matter pores,intergranular pores,intragranular pores（including clay mineral intergranular pores,pyrite intergranular pores and dissolution pores）and microfractures,and the pore structure is very complex.The main forms of pore gap are ink bottle type and parallel plate slit shape,and both macropores and mesopores are developed.The pore volume is mainly provided by macropores,and the specific surface area is mainly provided by mesopores.The shale of Funing Formation in Subei basin is rich in organic matter.Type I and type II1 kerogen are the main organic matter types,with moderate maturity and in the stage of thermal catalytic oil and gas generation.The fluorescent thin section of rock shows that the asphalt is mainly oily and asphaltene asphalt,and the asphalt content is medium to low.Organic matter abundance,organic matter type,organic matter maturity,porosity,specific surface area and lithofacies type all control the oil bearing property.S₂has the best correlation with TOC.The oil content of type I kerogen is better than that of type II₁kerogen,and the oil saturation of type II₁kerogen is higher than that of type I kerogen.There is a good correlation between organic maturity and S₂.Porosity and specific surface area have a good positive correlation with S₂.The content of S₁in organic calcareous shale is relatively high,and the content of S₂in organic rich siliceous shale is higher than that of chloroform asphalt"A".In general,organic rich siliceous shale and organic rich mixed shale have relatively good oil content.