Researches on Sequences Stratigraphy of Neogene in Huanghekou Sag, Bohai Bay Basin, China

Abstract

The Huanghekou Sag, as an important oil-bearing zone, is located in the southeastern part of the Bohai Bay basin. It has higher values for petroleum exploration-especially in Neogene. The Neogene was a depressional lacustrine period and was characterized with both tectonically stable and gentle topography. Thus it is difficult to identify and subdivide sequences using the traditional method. Based on the practical geologic setting and current data of the Neogene of Huanghekou Sag, using the new method to set up the isochronous sequence stratigraphic framework. By analyzing climate cycle, drilling well and logging cycle, seismic cycle and the identification of unconformity of seismic and drilling well and logging data, the Neogene was divided into 5 third-order sequences and 10 systems tracts. In different sequence sets and systems tract, which was controlled by climate, ratio rate between sedimentary being supplied and accommodated, the sand body scale was different.