Distribution features of lithologic and stratigraphic reservoirs in fault-depression basin

Exploration researches on lithologic and stratigraphic reservoirs in Erlian Basin and Jizhong Depression in recent years reveal that the different trap-forming mechanism and variance of reservoir-forming control factors resulted in unique distribution of lithologic and stratigraphic reservoirs compared to the structural reservoirs. Lithologic and stratigraphic reservoirs were mainly distributed along the “flood surface, unconformity surface and fault surface”. Those reservoirs could be distributed in the low or high potential areas and developed in the low system tract (LST) or the high system tract (HST). The distribution of lithologic reservoirs was mainly controlled by depositional system, and the distribution of stratigraphic reservoirs was mainly controlled by truncation zones and overlap zones. The enrichment degrees of them were mainly controlled by sedimentary facies and reservoir facies belts. The exploration of lithologic and stratigraphic reservoirs should be taken into attention. Exploration units must be reclassified by taking sedimentary system, stratigraphic overlap and denudation as the main control factors. More attention should be paid to the study on reservoirs controlled by the “flood surface, unconformity surface and fault surface” as well as by the sedimentary facies and reservoir facies. The exploration domains should be extended from ring sags to troughs, from positive structural areas to negative structural areas, from structural highs to structural flanks, and from structural zones to lithofacies zones, overlap zones and denudation zones.