Study on reservoir formation law of Upper Paleozoic coal-derived gasresources in Shaanxi Province

Based on the development theory and experiences of the coal-derived gas in Ordos Basin,in order to find out the reservoir formation law and favorable regions of the coal-derived gas in Shaanxi Province,a study was conducted on the features of the Upper Paleozoic hydrocarbon resource rocks in Shaanxi Province,the coalbed methane composition and the reservoir cover as well as other conditions and an analysis was conducted on the study achievements of the mature coal-derived gas exploration areas in Shaanxi Province and the surrounding regions.The results showed that the Upper Paleozoic hydrocarbon resource rocks in Shaanxi Province was high in thickness and the macerals were mainly the vitrinite,semi-vitrinite and inertinite.The metamorphic degree of the hydrocarbon resource rocks was high,the reservoir cover condition was good and the condition could have high hydrocarbon generation condition.The thickness of the hydrocarbon resource rock,methane generation intensity,deposition depth and others would be the experiment indexes to judge the development potential of the coal-derived gas in Shaanxi Province.The paper pointed out that the region from the south along the Zhidan-Zichang Line to the north of Huangling would have a good potential of the coal-derived gas reservoir.