Forming conditions and accumulation features of oil pools within the inner of highly buried-hills of Xinglongtai in west sag of Liaohe depression

Key words:  west sag of Liaohe depression  reservoirs in buried-hills  fissure reservoir  accumulation model of petroleum  system of migration passage

Abstract:

The structure, reservoir features and petroleum characterization for highly.buried-hills of Xinglongtai in west sag of Liaohe depression were studied by the data of the seismic, geological well measuring, DST, microscope measuring of reservoir and analysis of petroleum geochemistry. The results show that the newly found oil pools within the highly buried-hills of Xinglongtai in the west sag of Liaohe depression is different from the conventional oil pools near the top of the buried hills，and the reservoir within the highly buried-hills of Xinglongtai is a kind of fissure reservoir of Archaeozoic hybrid of metagranite, which is developed deeply within the inner of the buried-hills. The reservoir system of the highly buried-hills of Xinglongtai can be divided into two fluid dynamic systems，which are similar in the source and in the maturation of petroleum and different in system of migration passage. Petroleum in the shallow reservoir system near the top of the buried-hills migrates through the unconformity surface, while the petroleum in the reservoir of the inner of the buried-hills migrates through the fault-fissure carrying sys-lem. The faults play a very important role in the transporting of the petroleum from the Tertiary source rocks in the sag, and the fissures play a role in petroleum storing and a role in connecting the different reservoirs in microscale. The finding of reservoirs in the inner of the buried-hills foreshows a new potential area to explore in the deep horizons of the Bohai bay Basin.