This reference is for an abstract only. A full paper was not submitted for this conference.
The first field discovered in the ADCO concession came on stream in 1963 and is one of the largest Hydrocarbon accumulations in the UAE. In 40 years of production about 700 boreholes penetrated the main reservoirs, however virtually no seismic was acquired over the field.
In 2001, the decision was taken to acquire high-quality 3D seismic across the field after extensive field tests to optimize acquisition parameters and after incorporation of the learning's on the 3D seismic imaging in other ADCO fields. The actual seismic acquisition took 2 years over an 1800 km2 area with640 fold coverage in 12.5 m * 12.5 m bins. It resulted in an extremely high-quality dataset. Extreme care was given in processing to preserve amplitudes and frequencies to enable quantitative seismic attribute analysis. The seismic offers the unique opportunity to study a Middle East Carbonate reservoir after 40 years of production at an unmatched resolution of 100 Hz bandwidth at target level at 3 km depth.
Conventional interpretation started in conjunction with advanced seismic analysis (inversion & forward modeling while the data processing was still ongoing. The studies indicate that information on structure, rock properties and fluid effects can be extracted from the seismic to a much greater detail than possible in any other seismic dataset of ADCO. So far, immediate impact on the field development was obtained as:
several fault systems were observed and tied to the main orogenetic phases of the Arabian plate; inclusive of the Paleozoic and Proterozoic trends. Faults can be observed on seismic down to a throw of 5 ft and were confirmed by drilling results.
depositional geometries and stacking patterns within the main Carbonate reservoirs were detected. They were used to develop new insights into the reservoir depositional cycles;
Flat spots at the edge of the field and water-indicating isochron values around water injectors in the main reservoirs strongly suggest that fluid effects appear to be visible. Analysis on well and seismic data indicates that the effects of porosity and fluid change on the acoustic impedance can be separated in the studied Carbonate reservoirs.