Study On Lithology Identification Method Of Integrated ECS And Well-logging Data

The ECS well logging technology can directly determine the content of element which has been widely applied in oil-gas exploration and development.However,the main work of this technology currently is recognizing the major mineral of sedimentary rock and lithology of magmatic rock by using ECS,it has not established a method employing the well logging data of stratum element to identify the lithology difference between sedimentary rock and magmatic rock.This thesis is based on stratum element well logging data and compared with conventional well logging data,initially build the identification method of sedimentary rock,sedimentary rock and magmatic rock as well as key lithology group which has been applied preliminarily in different areas.1.Preliminary establishment about identification method of major lithology of sedimentary rock(1)In the classification of sedimentary rock based on mineral composition,the major rock types were identified according to the element crossplot of 10Si+5Ca+3Mg-5Al-5Fe and 5Ca+0.1Mg-5Al-1.5K+5Fe.The element crossplot has 6 zones including clastic rock zone,carbonate rock zone,clay rock zone,complex rock zone,coal and oil shale rock zone as well as mixing zone.Except mixing zone can not be identified by element crossplot,the identification accuracy of clastic rock zone,carbonate rock zone,clay rock zone,complex rock zone and coal and oil shale rock zone are 91.7%,90%,87.1%,78.1% and 90.6%,respectively.(2)The BP neural network tool was employed to identify the mixing zone of major rock types of sedimentary rock which can not be recognized by element crossplot.And the identification accuracy of clastic rock zone,carbonate rock zone,clay rock zone,complex rock zone are 87.9%,95.9%,95.1% and 81.4%,respectively.(3)The ECS data can not identify salt rock effectively,the crossplot of DEN,GR?DEN and AC was built to recognize the lithology of salt rock based on the severe well hole enlargement phenomenon,big sound wave and low density of well logging response characteristics of salt rock layers.2.Preliminary establishment about identification method of lithology between sedimentary rock and magmatic rock(1)The lithology between sedimentary rock and magmatic rock was identified according to the element crossplot of Si-2Al-3K and 30Fe+30K-30Ca-0.1Mg.The element crossplot was divided into 3 zones including sedimentar y rock zone,magmatic rock zone and mixing zone.The identification accuracy of sedimentary rock zone and magmatic rock zone are 90.1% and 92%,respectively.(2)The BP neural network tool was employed to identify the mixing zone of sedimentary rock and magmatic rock zone which can not be recognized by element crossplot.And the identification accuracy of sedimentary rock zone and magmatic rock zone are 93.9% and 94.3%,respectively.3.Preliminary establishment about identification method of lithologic group(1)The study note that the method to identify the four lithologic groups,including sand-fine grained rock group,fine grained rock group,gypsum-fine grained rock group and sand-fine grained-bedrock group based on the well-logging data,including AC?DEN?CNL,which are able to identify the porosity of clasolite,combined with ECS data.(2)Applying the method of four lithologic groups identification to gypsum-fine grained rock group in Qaidam Basin,sand-fine grained rock group in Ordos Basin,sand-fine grained rock group and fine grained rock group to Zhanhua Sag.