Research On Burial, Geothermal, Hydrocarbon Generation History In Wuerxun Depression Of Hailar Basin

As a secondary tectonic unit in Hailar Basin, Wurxun depression experiencedmulti-phased tectogenesis during the process of development and evolution and it is a typicalrift basin. Based on previous research, this paper is making a systematic research on burial,geothermal, hydrocarbon generation history in Wurxun depression. As a scientific basis for oiland gas exploration, burial, geothermal, hydrocarbon generation history in sedimentary basinplays a significant role in the research of hydrocarbon accumulation.Based on available data, statistics of lithology of each well and stratigraphic division aremade focusing on representative wells respectively in Wurxun depression. On this basis, thisstudy established compaction model, and with the application of correction formula, surfaceporosity and compaction coefficient are calculated. Finally, Basinmod is used to recover theburial history of representative wells in Wurxun depression.Combined with research results of burial history, Easy%Rois applied to recovergeothermal history of Wurxun depression. It is found that geothermal history of Wurxundepression accord with that of general rift basin. The paleogeothermal gradient, experiencedan evolution process which raised in the early stage and dropped in the later, averagely keepsat3.5℃/100m. During the analysis it is found that there are certain problems with applicationof Easy%Roto inverse geothermal history, namely, during the early phase of total geologicalperiods, geothermal gradient happened to have insensitive change, and is related with presentgeothermal gradient.Combined with geochemical characteristic of source rock in Wurxun depression,hydrocarbon generation potential of source rock is determined. Having integrated researchdata of burial and geothermal history, hydrocarbon generation history of Wurxun depression isrecovered by chemical kinetics. Therefore, the correlation between instantaneous,accumulated percent conversion and time was acquired. And it identified primary epoch ofhydrocarbon generation was130Ma~90Ma, duration was relatively short. This revealshydrocarbon generation epoch was started during the early stage of formation of the basin,and also reflects source rock is highly mature.