Concealed Canyons Delineation and Depositional Elements Analysis Applying a Multidisciplinary Geological and Geophysical Approach: A Case Study of the Pliocene Turbidites, West El-Burullus Area, Offshore Nile Delta, Egypt

Abstract

A detailed geological-depositional model and a clear understanding of the depositional elements of reservoirs decrease the drilling risks in the development of oil and gas fields. Building an effective geological model is a challenge in West El-Burullus (WEB) area because of its complicated reservoir, which consists of turbidite incised canyons system of Pliocene shales intercalated with sands. These canyons have occurred due to turbidity currents associated with the basin slope forming Kafr El-Sheikh Formation. Deducting the geological-depositional model and basins architecture is carried out utilizing the integration of seismic geomorphology, seismic facies analysis, sequence stratigraphy, and petrophysical analysis. The available datasets comprise a 3D seismic cube and logs of the WEB-1 well. Analyses of these data revealed various lithological facies relations and their paleo-depositional environments. This study demonstrated that Kafr El-Sheik Formation comprises a third-order sequence of turbidite units in-filling a canyon named WEB canyon with five sedimentary facies components: basal lobe through the incised old canyon, amalgamated channels fill, followed by splays, lobes, levees either proximal or distal facies, then the last plugged channels. Time–frequency spectral decomposition of time slices at the base and the top of the WEB canyon assisted the description of the litho-morphological and facies distribution of the concealed Kafr El-Sheikh Formation turbidity incisions and recognized reservoir trending and the canyon fairway. The turbidity facies with high reservoir quality was found in the overbank sedimentary distribution channels such as proximal levees and splays that reflected good to excellent petrophysical reservoir characteristics.