Logging evaluation of brittleness index of tight oil sandstone in Chang 8 member of Yanchang Formation in Yanchi area
Tight sandstone hydrocarbon resources usually need technical measures such as fracturing to ob-tain industrial production,and brittleness is a parameter for formation fracturing analysis,which is important for the selection of sweet spot in exploration and development of tight oil reservoir.Taking Chang 8 member of Yanchi Formation of Triassic in Ordos Basin as an example,the logging evaluation method of brittleness index is carried out.Firstly,based on the array acoustic logging data and the experimental test data of rock acoustic characteristics,the brittleness index is calculated by the rock elastic parameters such as Young's modulus and Poisson's ratio.Then,the calculatedbrittleness index is taken as the target value to find the corresponding relationship between it and conventional logging data such as gamma ray logging and acoustic logging.On this basis,a logging prediction model based on rock brittleness index is established.Finally,through multiple regression,the conventional logging information is extracted,and the multiple function evaluation model of brittleness index based on conventional logging data is established.According to the ex-ample of single wells,the brittleness index predicted by logging is well matched with the experimental re-sults.For quantitative prediction of brittleness index,the goodness of fit based on lithology index model,physical property index model and multiple regression model is 0.733,0.719 and 0.789 respectively,and the correlation is obvious,with a correlation coefficient of 0.936.
万方数据
维普
