Abstract:

The types and distribution of depositional systems and lithologic traps in the sequence stratigraphic framework are controlled by the syndepositional faults. It is a hot research topic in the petroleum geology field at present. The Dongying Formation in the north of Nanpu Sag including Laoyemiao-Dulin and Gaonan areas can be divided into a second-order sequence and four third-order sequences in the guidance of the theory of sequence stratigraphy, combined with seismic, logging and core data. There are three types of sedimentary assemblage styles under the control of boundary faults, palaeogeomorphology, sediment source and syndepositional faults. Controlled by Xinanzhuang boundary fault, source supply and palaeogeomorphology, a single-faulted steep slope pattern with fan delta and sublacustrine fan is developed in Laoyemiao, and the lithologic lenticular hydrocarbon reservoir is developed; a single-faulted steep slope pattern with nearshore subaqueous fan is developed in Dulin, and the lithologic updip pinchout reservoir is developed. Controlled by the Baigezhuang boundary fault and Gaoliu syndepositional fault, a multi-faulted slope pattern with thick layer fan delta front is developed in Gaonan, and the lithologic trap controlled by distributary channel sand and turbidite fan sand body is inclined to form.

Key words: syndepositional fault, depositional system, lithologic trap, Dongying Formation, Nanpu sag