Abstract:

Based on sequence stratigraphy, according to 1 340 wells, the authors analyzed the characteristic of hydrocarbon reservoirs enrichment in the sequence stratigraphic framework in Qikou sag. The research shows that hydrocarbon reservoirs enriched near the second order sequence interface in Qikou sag. The closer to the second order sequence interface, the more enriched the hydrocarbon was. In the internal sequence, hydrocarbon reservoirs mainly enriched in lacustrine expanding system tract and low stand system tract. However, each sequence presented some differences. Above the second order sequence interface, hydrocarbon reservoirs mainly enriched in lacustrine expanding system tract and low stand system tract which were under the maximum flooding surface. Under the second order sequence interface, hydrocarbon reservoirs mainly enriched in high stand system tracts. On the plane, hydrocarbon reservoirs mainly congregated near steep slope zone which was controlled by sag marginal fault. The flexure slope break was the least hydrocarbon enrichment zone, but the exploration potential of lithologic reservoirs was huge. Hereby, the author proposed the thought that second order sequence interface+corresponding system tract in the third sequence+correlatable sag slope break types=favorable exploration zone. It is the three elements coupling controlled the favorable exploration zone.

Key words: petroleum reservoirs, sequence stratigraphy, three elements coupling；Qikou sag, Tertiary