Application of seismic sedimentology in a fluvial reservoir: A case study of the Guantao Formation in Dagang Oilfield, Bohai Bay Basin, China.

A seismic sedimentology study was performed to analyse the complex fluvial reservoirs in the Neogene Guantao Formation in Kongdian Oilfield, Huanghua Depression. Three facies associations were identified by core and logging data, including bedload channel, mixload channel, and floodplain. Widely developed floodplain deposits beds were selected as the relatively reliable reference time surfaces. Stratal slices were generated applying the stratal‐slicing principle on two isochronous reference seismic events in Kongdian Oilfield. These stratal slices were used to analyse the distribution of sediments in a relative geologic‐time domain. The variety of sediment distribution observed on the stratal slices indicated that the fluvial channel systems of study interval had evolved from straight channel, sandy‐braided channel to combined channel. Sediment dispersal patterns were controlled by the change of accommodation (A) and sediment supply (S) rate. Setting with a low A/S ratio favours the development of fluvial environment and high A/S ratio favours the development of floodplain. Braided channel sandstones formed in a low A/S ratio depositional environment were generally thought to be excellent reservoirs. However, the muddy plug could damage the lateral continuity of sandbody, impede the fluid flow, and reduce the water‐injection efficiency. [ABSTRACT FROM AUTHOR]