Addressing Imaging Challenges in the Nile Delta, Results from Various Multi-Azimuth Towed Streamer Case Studies

The Nile delta poses a series of seismic imaging challenges for hydrocarbon exploration and development, throughout the entire section from the seabed to the deepest Cretaceous events at around 10km depth. In the Post-Messinian there are numerous mud volcanoes, some of which are currently active, others of which are buried beneath more recent deposits. Together with pockets of free gas, the mud-volcanoes lead to a very high degree of lateral variability of rock properties such as seismic velocity and seismic attenuation. The Messinian layer is the most complex unit in the Nile delta. It consists of layers of sands, shale and evaporites, which are highly disrupted by faults and lateral and vertical movement of mobile shale. The thick pre-Messinian sequence contains the majority of the hydrocarbon bearing targets and is generally less complex than the overlying Messinian, but seismic images of it are often detrimentally affected by inaccurate detail added to the upper units during velocity model-building (VMB). Examples are shown of these challenges from various areas of the Nile delta, and ways to address them with the aim of obtaining the best possible seismic image from the current available data.