Controls of structural evolution on the hydrocarbon accumulations of Urxun-Beier Depression, Hailar Basin
Ping Guidong1,2, LüYanfang1, Fu Xiaofei1, Kang Lin1, Zhou Qingqiang3
1. Faculty of Earth Sciences, Northeast Petroleum University, Daqing 163318;
2. Key Laboratory of Tectonics and Petroleum Resources, China University of Geosciences, Wuhan 430074;
3. No.8 Oil Production Company, Daqing Oilfield Co. Ltd., Daqing 163514
From "basin formation,source rock,hydrocarbon generation and petroleum accumulation" four aspects,each stage of structural evolution and their significance to petroleum geology of Urxun-Beier Depression in Hailar Basin are discussed. Dynamic mechanism of the basin formation is the role of late-orogenic extensional collapse after Mesozoic orogeny formed in the Sino-Mongolian border area,so the Hailar Basin nucleated as a passive rift basin. Tectonic evolution of Urxun-Beier depression experienced five stages including:intermountain residual basin stage,passive rift basin stage,active rift basin stage,rift-depression transformation stage and depression stage. During the passive rift stage,sediments of the middle member 1 of Nantun Fm.(K1n1)concussively deposited and are characterized by interbedded mudstone and sandstone,which is the excellent source rock, During the active rift basin stage,basin strong rifted,narrow and deep depression framework controlled the distribution of effective source rocks in the upper K1n1, During the rift-depression transformation stage,rapid subsidence of basin showed significant positive impact on maturation of hydrocarbon source rock,massive hydrocarbon expulsed at the Late Yimin Fm.(K1y)sedimentary period that control the primary reservoir's formation,at the end of the K1y sedimentary period,inversion occurred in the basin,some early reservoirs was destructed by active faults and oil was regulated to the Damoguaihe Fm. to form secondary oil pools. There are diverse types uplift belts formed along with the basin evolution,which compose the difference hydrocarbon favorable accumulation belt and control the distribution of reservoirs in different petroleum systems.