The Characteristics Of The Organic Geochermisity And Organic Facies Of Source Rock In Longtan Formation From Huaying Mount, Northeastern Of Sichuan Province

Sichuan Basin, a multicycle sedimentary basin, has been deposited a series of thick sedimentary rock since Sinian Period. Mudstone, coal and carbonate are very rich, which also establish the foundation of a large number of oil and gas in Sichuan Basin. Moreover, the northeast of Sichuan is the main oil and gas production areas in the southwest of China.This study uses organic geochemistry, geochemistry and other means to research the source rocks in Longtan Formation Huaying Mount of in order to determine the hydrocarbon potential of source rocks, depositional environment and source of parent material. Using several methods which are mutually authenticated, the source rocks in study area have an initial assessment and a dividing of the organic facies. Finally get the following results:The contents of total organic carbon, chloroform extract and total hydrocarbon in Longtan Formation show high organic content which is a good organic material enrichment horizon. The organic content indicates the tide which is decreasing at first and then increasing later from the top to the bottom of Longtan Formation. On the analyzing of the four groups' relative content of the soluble organic matter, normal paraffin hydrocarbons and biomarkers, the type of Longtan Formation belongs to typeâ…¡.The further study on sterane and terpane indicate that regular sterane of C27-C28-C29 shows a typical "L" type. Higher gammacerane reflects the source material of lower hydrobiont and algae, the formation of weak salt-reductive sedimentary environment. Changes of biomarkers in parameters of three-dimensional heterogeneous show that the source rock of Longtan Fonnation is in mature stage.The trace elements of Longtan Formation's source rock indicate the form of a lack of oxygen, coastal salt water-shallow marine enviroment. The productivity of Longtan Formation firstly decreases and then slowly increases.Finally the organic facies is CD type.