Organic Facies And Hydrocarbon Generation Characteristics Of Paleogene Source Rocks In The South Part Of The Junggar Basin

Many sets of source rock series are developed in the south part of the Junggar Basin,the oil and gas resources are rich and the exploration potential is huge.This paper takes the hydrocarbon source rocks of the Paleogene Anjihaihe Formation in the south part of the Junggar Basin as the main research object.Through systematic core observation and description,organic geochemical analysis,petrological analysis and hydrocarbon generation simulation experiments,the characteristics of hydrocarbon generating parent material,sedimentary environment,lithofacies and product of the source rocks of the Paleogene Anjihaihe Formation are clarified.It is clear that the main hydrocarbon-generating parent materials of the source rocks of the Paleogene Anjihaihe Formation deposited in lacustrine facies are Cyanophyta and Phanerochaete,which are characterized by early hydrocarbon generation,wide oil generation window,high oil generation density and high residual hydrocarbon content.Combined with organic geochemical characteristics and sedimentary structural characteristics,the source rocks of the Paleogene Anjihaihe Formation are divided into four lithofacies,and their organic facies are further divided into four types,namely,organic facies rich in pediastrum in deep lacustrine facies,A organic facies rich in pediastrum in semi-deep lacustrine facies,B organic facies rich in pediastrum in semi-deep lacustrine facies,and organic facies rich in pediastrum in shore-shallow lacustrine facies,further defining the characteristics of single well development,profile distribution and plane distribution of each organic facies.The hydrocarbon generation simulation experiments were carried out for different organic facies,and the hydrocarbon potential and product evolution characteristics of the organic facies of different source rocks were clarified.The resource potential of different organic facies source rocks is evaluated,and the main organic facies types of the Paleogene Anjihaihe Formation are identified.This paper not only has guiding value for the oil and gas exploration related to the source rocks of the Paleogene Anjihaihe Formation,but also has certain reference significance for the study of the source rocks of other basins,the division of organic facies and the evaluation of resource potential.