Logging evaluation of organic carbon in Chang73 subsection of Yanchang Formation in Ordos Basin
To effectively evaluate the quality of source rocks.Taking the shale of Yanchang Formation in Ordos Basin as the research object,this paper combined the well logging data and total organic carbon(TOC)analysis of cores and constructed the mathematical model among TOC,resistivity logarithm,and gamma ray by the multiple regression analysis method based on the measured TOC of Chang73 subsection.The error analysis between the measured and the predicted TOC at the buried depth from 2 456 m to 2 492 m in Chang73 subsection in well H317 shows that the error rate is 1.92％,close to the average error of plane theory of 1.88％.The model was used to calculate the TOC of the unmeasured interval and draw the plane distribution of Chang73 subsection TOC.It is found that the source rock TOC of Chang73 subsection in the study area are generally high(the average TOC in 80％of the regional area is more than 4％),and the source rocks have strong hydrocarbon generation capacity.The TOC range from 3％to 12％;and the highest could reach 28％.The TOC vary differently in the plane,and there is a decreasing trend from southwest to northeast,which indicating the Chang73 subsection is the main source of the Triassic rocks.
万方数据
维普
