Case history; seismic exploration in Egypt's Eastern Desert

Abstract

Abstract Although oil exploration has been performed in the Eastern Desert of Egypt for over a century, seismic reflection techniques have only been in use for less than a fourth of that time.In an effort to improve seismic imaging of geologic targets, many styles of acquisition and processing have been tested, accepted, or discarded. Over the last twenty-four years, seismic data acquisition has evolved from low-channel analog to high-channel digital recordings. The most difficult exploration problems encountered in these efforts have been the low-frequency and high-energy ground roll and depth of penetration when imaging the oil producing Pre-Miocene sandy reservoirs below the highly reflective salt and evaporites.Efforts have been focused on developing seismic processing procedures to enhance the seismic data quality of recently acquired seismic data and develop-ing new acquisition methods to improve seismic data through acquisition and processing. In older acquisition, the new processing has improved the seismic quality (vertical and lateral resolution), but it still retains a low-frequency character. In the newly acquired seismic data, however, there is improved reflection continuity, depth of penetration, and resolution. We attribute this result to the change from low-fold (6-24 fold), long receiver and source patterns (50 to 222 m) to high fold (96 fold) short receiver and source group (25 m), and spectral balancing in the processing. The most recent acquisition and processing have greatly improved the quality of the shallow seismic reflections and the deeper reflections that have helped unravel the structural and stratigraphic style of the deeper portions of the basin.