Element Geochemistry And Evaluation Of Zhang Jiatan Shale In The Southeast Of Ordos Basin

Shale thickness,total organic carbon content,brittle mineral content,silty laminae distribution and thickness are critical parameter evaluation of shale oil and gas,which is closely related to shale sedimentary environment.Therefore,studying the shale formation characteristics and evolution of sedimentary environment are of great significance for for shale oil and gas reservoir evaluation and prediction.This paper focuses on the key wells core observation for Zhang Jia shale in the south-eastern of Ordos Basin and use Niton Xl3 t 950 XRF instrument for intensive geochemical testing.We analysised,the ancient water depth,salinity and particle size characteristics of clastic sedimentary environment,ancient generate power,silty laminae thickness distribution and so on during the shale deposition process.We used statistical methods to establish a quantitative relationship between the TOC and the elements and explored its internal relations,the we applied Y22 well measured data to validate the quantitative relationship;we established a quantitative relationship between the shale minerals and TOC.We summary the previous research of shale and proposed a set of indicators to predict elements silty laminae.The we established the method of facies prediction based on shale facies silty laminae,TOC and brittle mineral content.Finally,We proposed shale gas exploration and development wells Y22 dessert base on facies distribution,paleoenvironmental evolution of shale and TOC and brittleness index distribution.The main understanding are the following:Compared with traditional laboratory-situ XRF instrument,Niton Xl3t-950 elemental analyzer holds the high-resolution,high accuracy,the advantages of rapid testing.Compared with the average value of the North American shale,the element of Rb,Fe,Zr,P,Ba,Zn,V,U,Ni,is more enriched of Zhangjiatan shale;Sr / Ca,Zr / Rb,P / Ti,Ba / Ti hold a higher ratio.compared with pure shale,Silty laminae relatively enriched Ca,Mg,Sr,Cl,Zr;V / Ni,Sr / Ba,Sr / Ca,Zr / Rb,Ca / Ti,Sr / Ti,V / Cr,Th / U,Sr / Cu is relatively high.Based on the variation of Element abundances and ratios in the longitudinal direction,the Zhang Jiatan shale can be divided into 11 quite different units.During the deposition process of Zhang Jiatan shale,the ancient climate,ancient water depth,salinity ancient,ancient redox environment,productivity and other aspects of ancient cyclical changes.(4)unit which during the deposition of the most humid climate,water depth reaches a maximum,the higher productivity of ancient sedimentary medium,strong reduction of water conducive to the preservation of organic matter.We used cluster analysis,variables and multiple regression methods,properties,selected trace elements closely related to hydrocarbon source rocks.The regression equation of TOC and U,Zn,S Ba.We also established a quantitative relationship between the elements of shale mineral,then we proposed the approach of characterize the relative amounts of mineral applications brittle fragility index.We proposed the parameter identificated Silty laminae and divided Y22 well facies based silty laminae,TOC and brittle mineral.In the end,We carrid a comprehensive evaluation and the corresponding exploration and development dessert for Zhang Jiatan of Y22.