Abstract:

During the depositional stage of the Kongdian Formation of Eogene (Ek), Dongying depression was on the early rifting stage The change of the accommodation differed with areas. The accommodation in the Niuzhuang-Liuhu area became larger, and at the same time, the accommodation in Bamianhe area became less. The decreasing of the accommodation controlled that the sandbodies were well-developed, the oil-generated source rock was lack and the traps were  structural trap, litho-structural trap and strata trap in the Bamianhe area. The deposition system of alluvial fan-fluvial-flooding plain taked up the filling of the first member of Kongdian Formation (Ek₁) in the Bamianhe area, and the sandbodies mainly consisted of siltsand. It was conformed by the dark mudstone in well Wang46 that the second member of Kongdian Formation (Ek₂) had the ability of oil generating, so besides of the fourth member of Shahejie Formation oil-generated source rock, Ek₂ was another source rock. The welldeveloped faults and the unconformities could be the accesses of oil migrating. Under the acting of all kinds of factors, the oil traps were formed and the the oil traps consisted of structural oil traps, structural-lithological oil traps and sub-crop oil traps.

Key words: Kongdian Formation, oil-pool forming condition, accommodation, the Bamianhe area