3D Seismic for Exploration, an Integrated Process from Acquisition to Interpretation

By

 Naema Obaid Al-Zaabi¹, Saleh A. Bin Sumaidaa¹, Jean Francois Dervieux¹, Abu Baker Al Jeelani¹, Erik Bernardus Kleiss¹, Mohamad Samir Al Nahhas¹

(1) Abu Dhabi Company for Onshore Oil Operations (ADCO), Abu Dhabi, United Arab Emirates

 The large four way closures have been found. The remaining traps require high quality and densely sampled data to properly explore, evaluate and risk prospects. 3D seismic can be used cost effectively to derive useful information for pure exploration.

This example shows 3D data over an area dominated by large sand dunes alternated with sabkha plains generating static problems, and with severe surface and internal multiples. A careful acquisition design and processing sequence and the involvement of an integrated team of geophysicists and seismic interpreters have lead to excellent results.

'Wide-line' or 'Sparse' 3D seismic data have been acquired with relatively large source- and receiver line spacing, low sweep effort per source point but with long offsets and still reasonable fold, as compared to field-development 3D's. Despite these economised parameters, the final result is very detailed. Structural and stratigraphic features can be highlighted using attribute mapping and 3D visualization tools. Seismic amplitudes relate to reservoir porosity and are a valuable risking tool. The data allow a better geological understanding of the area both in structure and stratigraphy. These good data provide a higher degree of confidence and improve the risk evaluation associated with each of the multiple exploration prospects.

These high quality data are the result of working as an integrated team; a case history showing the importance of such teamwork on optimizing all steps of the geophysical process in a difficult terrain.