Characteristics And Distributions Of Chang 7 Source Rock In Ordos Basin

The essay is based on some collected geochemical data of Chang 7 source rock,and then supplement some specific samples to make some necessary observations and geochemical analysis.The source rock of Chang 7 member Yanchang formation in Ordos Basin mainly consists of shale and mudstone,its TOC is very high,and the organic matter is mainly type ? and ? 1,the average Ro is 0.85%.By elemental analysis we can know that Chang 7 source rock had high productivity in ancient,and deposited in humid climate and anoxic freshwater.Developed in the heyday,the source rock form in the semi-deep and deep lake is widely distributed along Jiyuan-Huachi – Yijun.The monolayers of Chang 7 effective source rock are thick,from the bottom to the top they gradually become thinner and the lateral continuity is deteriorated.The distribution of TOC is similar to the thickness of source rock,along Jiyuan-Huachi – Yijun TOC is very high,the average TOC is up to 10% or more.Take Longdong region for example,calculate the hydrocarbon generation intensity and volume of Chang 7 source rock.The results showed that the maximum hydrocarbon generation intensity is up to 600,the products is mainly oil.The total hydrocarbon volume of Yanchang formation in Longdong area is 744.82,the contribution rate of Chang 7 effective source rock reaches 73%.