Characteristics And Application Of Biomarker Compounds Of Marine Source Rocks In The Sichuan Basin

With the sedimentary tectonic evolution of basin, before the late Triassic in Sichuan basin is characterized by Marine sedimentation. On the longitudinal there are seven groups of hydrocarbon source rocks from bottom to top:Z2d, Z2dn3, ?q, S1l, P1q-m, P21,P2d in the marine sedimentary of Sichuan Basin. It has important significance to understand the characteristic of biomarker compounds of hydrocarbon source rocks and its application for reservoir exploration and development. By using research methods of indoor combined with outdoor, micro contact macro, gas chromatography-mass spectrometry, isotope analysis, and other advanced means of geochemical research to study the samples of hydrocarbon source rocks, obtained the following understanding:1.Thesis research involving seven sets of hydrocarbon source rocks whose main lithology include:black shale black mudstone, argillaceous limestone,etc. The distribution of seven groups of hydrocarbon source rocks is different in the basin. The thickness of hydrocarbon source rock ranges from a few meters to a few hundred meters. The overall organic carbon content is high in most hydrocarbon source rocks. Most of hydrocarbon source rocks achieve high-post mature stage.2.There are a lot of common in characteristic of biomarker compounds of marine hydrocarbon source rock, such as the content of phytanic is relative higher than pristine, C28'C29long chain tricyclic terpane, and C24 tetracyclic terpane are visible, C30 hopane is the main peak of pentacyclic triterpene series, ratios of pregnane/L pregnaneis are more than 1, relative content of rearrangement sterane is far lower than the relative content of regular sterane. But some characteristics of biomarker compounds still exists a certain degree of difference. For example, the relative content of C28 triaromatic sterane, ratios of C29/C30 hopane and ratios of C35/C34 hopane of samples in Permian and Silurian are higher than those in Sinian and Cambrian, while the gammacerane index is lower.3.By doing research and analysis of natural gas composition, carbon isotope and the characteristic of reservoir bitumen biomarker compounds of Anyue gas field, we think that natural gas mainly come from black shale of ?q.4.By studing and analysing the composition of natural gas, carbon isotope characteristics of gas reservoir and the characteristics of reservoir bitumen biomarker compounds in T1f and P2ch of Puguang gas field, we think that Permian hydrocarbon source rocks is considered the main source of Puguang gas field.