Seismic Characteristics and AVO Response for Non-Uniform Miocene Reservoirs in Offshore Eastern Mediterranean Region, Egypt

Abstract

Abstract The Eastern Mediterranean region, extending from the Offshore Nile Delta Cone of Egypt to the Levant Basin, is a confirmed hydrocarbon rich territory with several giant gas discoveries. Numerous gas fields have been discovered in the Miocene reservoirs within the Nile Delta Cone, and in the Levant Basin. The Miocene sedimentary sequences in this region are extremely heterogeneous, consisting mainly of turbiditic slope deposits, channels, and basin floor fans that were capped by evaporites during the Messinian Salinity Crisis. As a result, there is ambiguity regarding the seismic characteristics and interpreted attributes of this heterogeneous section. The study area is located in the Offshore North Sinai Basin, where a thick Early Miocene section was deposited midway between the Nile Delta province that includes El-Fayrouz discovery and the Levant Basin which includes Tamar, Tanin and several other discoveries. This study uses quantitative seismic interpretations methods, such as amplitude variations with offset (AVO), fluid replacement modeling to assess the seismic acoustic impedance trend with depth. Also, determine the seismic amplitude response for the brine and gas sands reservoir of the Early and Late Miocene section, to link the unexplored study area within the North Sinai Offshore basin with the explored Nile Delta and Levant Basins. In addition to evaluate direct hydrocarbon indicator (DHI) of the diming seismic amplitude that is compatible with the structure last closed contour of the Syrian Arc anticline of the Early Miocene reservoirs (EMT-1 prospect). Different ventages of 2D & 3D seismic data, 6wells and different published data used in this study. The quantitative interpretation shows the pitfalls of the acoustic impedance trend and seismic response dependency on depth for gas and brine sand which lead to drill EMT-1 dry well. Also, the fluid replacement, P-wave velocity (Vp) and density (ρ) modeling confirming that the seismic diming amplitude is due to seismic processing uncertainty, which solved by readjust the overburden Messinian salt processing velocity model. This research concluded that the seismic quantitative interpretations were successfully used to assess the acoustic impedance versus depth and DHI pitfalls., also, assess the processing workflow that could enhance the seismic image.