Geological Research On Hydrocarbon Expulsion Efficiency Of Shale In The Typical Basin Of China And The United States

The success of the North America tight oil exploration and development make tight oil has the potential to be the important energy after shale gas,and tight oil include mud shale oil and oil in thin interbedded sandstone or limestone,among tight oil,the sandstone oil is part of the discharge oil of the shale,while mud shale oil refers to the residual oil in the shale.as a result,the hydrocarbon expulsion efficiency directly affects the abundance of hydrocarbon accumulation and resource,and determine the direction of exploration and field.To find out the global tight oil resources distribution,is of great significance in order to reveal the characteristics of hydrocarbon expulsion of different types of mud shale.The global tight oil and gas are found in hundreds of basin,mainly concentrated in North America,Asia,Russia,and South America.Among these tight oil basins,the tight oil resource is most rich in North America,Asia's second.Therefore,this article mainly take the typical tight oil basin of China and the United States as an example,Through the detailed analysis of conventional geochemical data,such as organic carbon,rock pyrolysis,the characteristics and influencing factors of hydrocarbon expulsion of different types of mud shale is discussed,aiming at evaluating the tight oil resource potential in the global basin evaluation and helping to optimize favorable tight oil basin.This paper analyses the organic type,abundance,and maturity of mud shale in the typical tight oil basin of China and the United States,and evaluates the hydrocarbon generation potential.The method of the original potential of hydrocarbon generation and material balance are applied to calculate hydrocarbon efficiency of mud shale,combined the method of logging technology to realize the longitudinal continuous distribution of organic matter,and summarize the main influencing factors of hydrocarbon expulsion efficiency,such as organic matter quality,sedimentary facies,and buried ways.The results are showed as below: values of organic carbon in the United States basin is generally higher than domestic's,the former is given priority to ? type,the latter distributes the organic matter types of?,?,?,and the former has low maturity.When the organic matter type and maturity is relatively stable,the hydrocarbon expulsion efficiency first increases and then decreses,the boundary of the hydrocarbon expulsion efficiency of shale in China and the United States basin are 2~3% and 6% respectively.When organic matter abundance and maturity is relatively stable,the better organic matter type,the greater the amount of organic matter hydrocarbon generation per unit mass and the lower adsorption quantity of kerogen,which leads to the higher efficiency of hydrocarbon expulsion efficiency;When the organic matter abundance and type of the shale is relatively stable,the higher the maturity,the greater the hydrocarbon expulsion efficiency.Among the different accumulation combination ways,the type of nested mudstone> the type of sand and mud interaction> the type of nested sandstone> the type of thick mudstone.Thickness of the thick mudstone is greater,its average hydrocarbon expulsion is lower,and the hydrocarbon expulsion efficiency in middle thick mudstone is lower than its edge.The hydrocarbon expulsion efficiency of continuous deposition of source rocks is higher than in lifting hydrocarbon source rocks;Among the different rock phases,the hydrocarbon expulsion efficiency of delta plain> delta front> lacustrine facies,with shale/stratum value increasing,mineral particle size tapers and clay mineral content increases,which results in the hydrocarbon expulsion efficiency gradually reduced.The differences in reservoir type between Bakken Formation and Eagle Ford Formation is mainly controlled by hydrocarbon expulsion efficiency.