Quantitative characterization and control factors of shale oil occurrence state in the shale of member 2 of Fu-ning Formation in the Gaoyou Sag,Subei Basin
In view of the fact that the occurrence state of shale oil has an important influence on the en-richment and mobility of shale oil,taking the member 2 of Funing Formation shale in the Gaoyou Sag of the Subei Basin as the research object,a variety of techniques including multi-temperature pyrolysis and laser confocal microscopy were used to quantitatively characterize the occurrence state of shale oil,and to clarify the controlling factors of its occurrence state.The results show that the occurrence state of shale oil in the member 2 of Funing Formation shale in the Gaoyou Sag can be divided into two catego-ries:free oil and adsorbed oil.Free oil is the main type,accounting for an average of 65.16％of the to-tal oil content.There are significant differences in the occurrence state of shale oil among different litho-facies.The proportion of free oil from high to low is siliceous shale,siliceous-calcareous mixed shale,calcareous-clayey mixed shale and calcareous shale.Organic matter maturity,total organic carbon w(TOC),mineral composition,and pore structure are among the various factors that jointly control the occurrence state of shale oil.The content of free oil and adsorbed oil is mainly controlled by w(TOC)and pore structure.The amount of free oil is weakly positively correlated with w(TOC),while the a-mount of adsorbed oil is strongly positively correlated with w(TOC).Both the content of free oil and adsorbed oil are positively correlated with pore volume,while their correlation with specific surface area is not significant.The relative proportions of free oil and adsorbed oil are primarily influenced by organic matter maturity,silica mineral content and pore structure.The proportion of adsorbed oil decreases with increasing organic matter maturity,while the proportion of free oil is weakly positively correlated with the content of long-chain alkane minerals.The more developed the macro-pores and micro-cracks,the higher the proportion of free oil.These research findings are of great significance for guiding the ex-ploration of shale oil in the Subei Basin.
Subei Basinmember 2 of Funing Formationshale oiloccurrence statefree oiladsorbed oilcontrolling factorsGaoyou Sag
万方数据
维普
