Study On The Reservoir-forming Process And Exploration Directions Of Coal-derived Oil And Gas From The Permo-Carboniferous In The North Of Jizhong Depression

Twenty years ago, coal-derived oil and gas from the Permo-Carboniferous in Suqiao-Wenan area Jizhong Depression had been discovered. But there are many problems in resource potential and reservoir-forming process. With a great deal of relative documents and the comprehensive study of geological and geochemical and geophysical data, the law of reservoir-forming of coal-derived hydrocarbon in the north of Jizhong Depression is studied in the evolvement of coal sequence and the character of the coal-derived oil and gas reservoir and the process of reservoir forming.The Permo-Carboniferous in the north of Jizhong Depression bends to the west. The"teeterboard"like evolvement of tectonic history leads to the distributing of coal and mud in lack nowadays, that is Ge2-Ge5-Wen23 well area is the thickest, other area is thinner and thinner.Using the technology of creating basin simulation model to do research of depression evolutionary process in hydrothermal stage and hydrocarbon-forming process. The Permo-Carboniferous has two main hydrocarbon-forming histories, that are the end of Cretaceous period and Paleogene times until now.Study proves that the secondary hydrocarbon generation is very critical .Wenan-Yangcun slope and Hexiwu slope and the deep sag of the slope are favorable zones, while the uplift area has no secondary hydrocarbon generation after Trias period.So far the earliest hydrocarbon generation is at 39.5 Ma in Hexiwu slope, and the latest one is at 12 Ma in Wenan slope.The gas found is mainly concentrated in Suqiao-Wenan belt.Of the coal-derived gas, there is almost 80 percent methane, while weighty hydrocarbon is more than 11 percent.δ13C1 is between -35.6‰~-38.2‰.IMCC6 is more than 50 percent. 40Ar/36Ar is more than 500 in noble gas. The characters of the associated oil is that pr/ph >1 and n-paraffin hydrocarbon (C28