Relationship Between Element,Sedimentary Rock Lithology And Mineral Content And Its Application In ECS Logging Interpretation

The relationship between element, sedimentary rock lithology and mineral content is the key to application of elemental capture spectroscopy logging. There is no unified understanding about the relationship between element, sedimentary rock lithology and mineral content abroad. And there are few systematic research about it domestic, that will affect the elemental capture spectroscopy logging technology's development in domestic.This paper use the relationship between elements and sedimentary rocks as the key point, analyzing the relationship among the elements and the sedimentary rock lithology and mineral assemblage.At first, collecting and analysising mineral content of more than 9000 piece of sedimentary rocks throughout the main petroliferous basin. According to the mineral composition, more than 9000 piece of sedimentary rocks are classified. And calculating its corresponding element content.By researching the relationship between element, sedimentary rock lithology and mineral content through a series of single element and multi elements crossplot, establishing Si and Al, Si and Ca, Si and 5Ca+0.1Mg-5Al-1.5K+5Fe,10Si+5Ca+3Mg-5Al-5Fe and 5Ca+0.1Mg-5Al-1.5K+5Fe crossplot chart to identificate sedimentary rock lithology, the coincidence rate can basicly reach more than 90%, establishing Si-Al-K and 0.1 Ca+Mg+Fe-K crossplot chart to distinguish between quartz clastic rock and feldspar clastic rock, the coincidence rate are 92.2% and 81.3%, establishing Ca and Mg to distinguish between calcite carbonate and dolomite carbonate, the coincidence rate are 97% and 96%.Based on identification of sedimentary rocks and analysis of the relationship between mineral content and element content in different lithology of sedimentary rocks, establishing the formula to calculate quartz, feldspar, clay, calcite, and dolomite content of quartz clastic rock, feldspar clastic rock, clay rock, calcite carbonate, dolomite carbonates, miscellaneous rock with element content.Apply the chart of sedimentary rock lithology and formula for the calculation of the main mineral content in different sedimentary rock lithology with element content in elemental capture spectroscopy logging, which can quickly identificate sedimentary rock lithology and roughly calculate its mineral content.