| The Dachanggou Basin is located in Balikun area,Xinjiang.The basin type is a small continental depression basin,and the organic-rich fine-grained sedimentar y rocks are widely developed.It is a high-quality oil shale deposit under development in China.The development time of the study area is late,and there is almo st no systematic study on the sedimentary characteristics and oil shale resources in this area.Therefore,this work conducted in-depth r-esearch on the characteristics and distribution law of oil shale in the study area through core observation, sample test and analysis,and combined with quantitative identification of oil shale logging.The core observation and sample test analysis of fully coring wells ZK0010 and ZK1601 in Dachanggou Basin show that the oil shale in the study area is mainly hosted in the Badaowan Formation of the Lower Jurassic,and there are 14 layers of continuous oil shale de-posits with a total thickness of 74 m.Oil shale is gray-black,developed horizontal bedding,with high oil content,belongs to medium-high quality oil shale.Oil shale organic matter types are mainly II1 and I,or ganic matter abundance is very good,organic matter maturity is in immature-low mature stage.By interpreting the logging data of ZK0010 and ZK1601 wells,the B-P neural network model of lithology-logging curve in this area is established,and the lithol ogy of other wells is identified by logging.The lithology obtained by inversion is more refined than that of the collected well data.By establishing the ?Log R model of the organic carbon-logging curve in this area,the TOC and oil content are calculated and predicted.The obtained evaluation oil shale parameters have a good effect on the identification of oil shale.Two types of sedimentary facies,delta facies and lacustrine facies,are developed in the Badaowan Formation of the study area,which are further divided into four sedimentary sub-facies and eight sedimentary microfacies.Delta facies is mainl y divided into delta plain subfacies and delta front subfacies,which are located in the west and east of the study area,and also the main provenance of the study area.The lacustrine facies are mainly divided into shallow lake facies and deep lake-semi-deep lake facies,which are mainly located in the ce-nter of the basin,and are also the main development facies belt of oil shale.Sequence stratigraphic framework of Badaowan Formation in Dachanggou Basin was est-ablished according to sequence identification marks such as drilling lithology combination and logging curve.Three third-order sequences were developed in the study area.Sequence II developed five layers of industrial ore shale,of w hich two layers developed in the HST,andthe other two layers developed in the RST and LST,respectively.The three layers of high quality oil shale in sequence II are studied.It is found that the thickness near the center ofthe basin is large and the oil content is high.Finally,combined with the thickness,oil con-tent,plane distribution and miningability,it is concluded that L7 layer is the optimal oil shale,followed by L6 and L11 layers.By predicting the spatial distribution characteristics and resource potential of oil shale in Dachanggou area,it has certain practical significance for further exploration and developmentof oil shale. |
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