| The Laoyemiao area of Nanpu Sag has developed slope-controlled sand-type reservoirs. The middle and deep
strata in this area are rich in oil and gas resources and have broad exploration prospects, where is an important replacement
area for exploration and development. At present, there are some problems in this field, such as deep burial depth, weak
effective seismic signal, rapid lateral change of sand body and unclear description of sand body shape, which restrict the
deployment of high-efficiency wells and the tapping of remaining oil in reservoirs. Based on the analysis of core, logging
and seismic data in the study area, a new seismic sedimentary interpretation method for “three domains and three
elements” has been explored, which includes three seismic sedimentary interpretation methods, such as stratigraphic
structure identification at energy half-life, sequence stratigraphic tracking by minimum cost function method and
lithology identification by relative Poisson's ratio. It is shown that : (1) The sedimentary body of upper submember of the
Dongying Member 3 in the study area has the sedimentary characteristics of “bottom gravel and top sand” in the
longitudinal direction, that is, nearshore subaqueous fan deposition is developed at the bottom and braided river delta
deposition is developed at the top. (2) The upper submember of the Dongying Member 3 in the Laoyemiao area is
bounded by the Laoyemiao strike-slip fault conversion zone, and multiple point dams are developed to the north of the
boundary, showing sand island deposition; the fan delta sedimentary system is developed in the south of the boundary.
From the early deposition to the late deposition, the scale of the fan body first expands and then shrinks, and the shape
gradually evolves from the skirt shape to the narrow strip underwater distributary channel deposit, and the fan body is
closed to the oil source fault, so it is the replacement area of exploration and development. (3) The method of “three
domains and three elements” seismic sedimentary reservoir characterization has good applicability for sedimentary
microfacies characterization and favorable reservoir distribution prediction in complex structural areas, and the
coincidence rate of sand body thickness prediction reaches 90%. |
