Log Evaluation Method For TOC In The Lucaogou Highoil Formation In The Jimsar Sag

Evaluation of TOC logging in shale has the characteristics of low cost and continuity,the method have always been a hot issue in geological and engineering research.Firstly,based on resistivity series-parallel model,solid-filled Gassmann equation and K-T equation,the resistivity and slowness model of the source rock are established respectively,and the model is used to characterize the resistivity and slowness of source rock under different conditions.According to the principle of the ?logR method,combining the acoustic and electrical models of source rocks,find the composite coefficient k of different formation and oil-bearing state,modified logR method.Secondly,based on the example of the Jimsar area in the development of high-quality source rocks,the application effect of the improved ?logR method combined with acoustic and electrical equations is studied.It is found that the recognition ability of the original ?logR method in the oil layer is susceptible to hydrocarbons,the accuracy of evaluation is low when the fixed k value is 0.02.Further,the TOC content evaluated by the ?logR method after determining the coefficient k by lithology and saturation is closer to the core data because the interference factor is excluded.In theory,the modified ? logR method takes more factors into account and has higher accuracy.After improvement,there is a good correspondence between the measured TOC and the calculated TOC,and the evaluation error of each well is reduced by 15% on average.