Reservoir-Forming Conditions to the Damoguaihe Group of Urxun-Beier Depression in Hailaer Basin

In order to understand the oil and gas accumulation conditions of Damoguaihe Group in Urxun-Beier depression, stratigraphy, structural geology and reservoir system theories and methods have been used in this paper.Faults of the Depression experienced three stages which were the extensional deformation period between Tongbomiao and Damoguaihe Group, the strike-slip deformation period in Yimin Group and the the strong inversion deformation period between Qinyuangang Group and the late stage of the Paleogene respectively. The formation of Damoguaihe Group could be divided into three third sequences and farther fifteen sand layers. Different stages controlled different sedimentary evolution processes. The oil in the Damoguaihe Group came from the Nantun Group and mainly from the first member of it. There are two migration wayspp. 1. When the displacement of fault was larger than 300m, the source rock of the Nantun Group connected with the reservoirs of the Damoguaihe Group, and thus constituted the lateral generation and side storage reservoir.2. After a vertical upward migration along the source faults (unconformity)from the Nantun Group to the Damoguaihe Group and a short distance lateral migration, down-genetic and upper-stored reservoir type was formed and it could be summarized as the structural, lithological, stratigraphical and lithological - structural reservoirs.