High-resolution sequence stratigraphy of fan deltas and its relations to oil and gas accumulation:A case study of the T76 block on the falling wall of the Shengbei fault in the Dongying depression, Shandong

The division and correlation of sequence stratigraphic units are constructed for the fan delta deposits in the upper submember of the 4th member of the Shahejie Formation in the T76 block on the falling wall of the Shengbei fault in the Dongying depression, Shandong on the basis of geological data, seismic sections and well logs. These fan delta deposits are divided into 4 parasequences, 18 bed sets and 29 beds. In the fan delta depositional system, the boundaries of the parasequences and bed sets are changed with the geographic positions, whereas in the base-level cycles of the parasequences and bed sets in a single facies, the porosity and permeability are the function of A/S ratios. The physical properties and oil saturation in oil reservoirs also display similar regular changes.