Abstract：

　　As for the Mesoproterozoic strata (1 800~1 327 Ma) in Jibei Depression, Yanliao Faulted-Depression Zone, there are 2 sets of hydrocarbon source beds (i.e., Gaoyuzhuang Fm. black micritic dolomite and Hongshuizhuang Fm. black shale) as well as 3 sites of the basal bitumenous sandstone fossil-oil-reservoirs in Xiamaling Fm. respectively at Longtangou, Shuangdong and Lujiazhuang. The bitumenous sandstone has two phases of solid bitumen components (SBCs): the early SBC with 1.68%~2.52% in bitumen reflectance Rb and the late one with 0.81%~1.01%. Owing to emplacement of gabbro-diabase sills, palaeo-oil-reservoir had been alterated into bitumenous sandstone (i.e. fossil-oil-reservoir), whereas viscous oil seepages found within wall-rock alteration zone provide an evidence for late oil migration and filling after the magma cooling and consolidation. The discovery of bitumenous sands can indicate that early oil filling and entrapment process would be started at the early diagenetic period of basal sandstone in Xiamaling Fm. (~1 400Ma), while its alteration age would be determinated according to the emplacement age of Xlamaling Fm. gabbro-diabase (1 327Ma). Based on the stratigraphic sequence and stratum thickness analyses, it could be defined that early oil filling and entrapment of Xiamaling Fm. basal oil reservoir could only be sourced by the Gaoyuzhuang Fm. source bed, it’s threshold depth of hydrocarbon generation would be around 3 600 m. On the basis of the threshold depth, the oil entrapment age from the Hongshuizhuang Fm. source bed should be at the Mesoproterozoic period. Oil correlation results show that all the oil-seepages found in the Wumishan and Tieling Fms. and the Late SBC extracts of Xiamaling Fm. basal bituminous sandstone are sourced by Hongshuizhuang Fm..

Key words： mesoproterozoic xiamaling formation basal bitumenous sandstone fossil-oil-reservoir oil entrapment age threshold depth of hydrocarbon generation

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Cite this article：Wang T -G,Zhong N N,Wang C J, et al. Source beds and oil entrapment-alteration histories of fossil-oil-reservoirs in the Xiamaling Formation basal sandstone, Jibei Depression[J]. 石油科学通报, 2016, 1(1): 24-37.

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