Multi-azimuth 3D provides robust improvements in Nile Delta seismic imaging

Abstract

Since gas was first discovered in the Nile Delta in the late 60s, most exploration programmes have focussed on shallow Pliocene reservoirs, where gas can clearly be seen as bright events on excellent quality seismic data and where exploration success has been very high. The petroleum geology of the deeper pre-Pliocene section is fundamentally no different to that seen in the Pliocene, where potential reservoirs consist of sand prone channel systems originating from the Nile. Why then, have we been deterred from exploring in the deeper section? The problem is two fold: 1. Deeper burial and harder rocks mean that reservoir sands and hydrocarbons will be less visible on our seismic data. 2. Pre-Pliocene seismic quality is highly variable and often very poor. (Figure 1) Poor imaging being the result of wavefield distortion though the Messinian anhydrite layer, attenuation, and the presence of complex multiple diffraction noise.