Lithofacies interpretation at the upper part of the Pokurskaya formation in the Cenomanian succession, the north of the West Siberian Basin

The lithofacies of the Cenomanian succession within a gas field in the north of the West Siberian basin were studied using well log information especially spontaneous potential log to determine the lithostratigraphy, hydrodynamic characteristics, possible reservoir sands and depositional environment of the study area for opportunities that will support the exploration program. Geophysical well logs from six profile wells were used for this study. The lithostratigraphic model and sequence-stratigraphic frame were developed using spontaneous potential log curves to identify lithic units like sand, silt and mud. The depositional environments penetrated by the wells interpreted from log signatures gave four main types of lithofacies: Foreshore, Regressive Shoreface; Transgressive Shoreface; Discontinuous Currents were recognized from the stacking patterns of the spontaneous potential curves by modified electro facies classification. The stratigraphic column of the wells was subdivided into parasequences composing four sequences within the regional stratigraphic trend.