Albian Clastic Prograding System in the Dunga Field (Western Kazakhstan) From Regional Understanding to Prospectivity

The Lower Cretaceous series of the Mangyshlak Basin in Western Kazakhstan mainly consists of clastic sediments characterizing continental to marine depositional environments. The overall basin records at that time a large wavelength subsidence without major faulting, involving eustasy as the main controlling factor on sedimentation. The lower to middle Albian interval in the Dunga license is characterized in seismic by a set of well-imaged clinoform geometries prograding from East to West at the base, passing upwards to more sub-parallel and horizontal reflections. The clinoform sequence in the lower section is interpreted to represent a shoreface/delta environment. The upper interval is interpreted as an extensive aggrading offshore to shoreface environment. The complex stratigraphic architecture of this clinoform system creates lateral and horizontal facies changes, increasing the chance of stratigraphic traps with internal reservoir-seal pairs. The Albian play has initially been proved by Maersk Oil in 2012, and further prospectivity is supported by the indications of hydrocarbons identified on wireline logs and mudlog data. A geological model has been constructed based on seismic interpretation of geometries, facies analysis from multiple wells and core data in order to better understand the remaining prospectivity within this sedimentary system.