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7th Middle East Geosciences Conference and Exhibition
Manama, Bahrain
March 27-29, 2006
PDO, Muscat, Oman, phone: +968 24672854, [email protected]
Fahud, PDO's largest field, produces oil from the Natih fractured carbonates. Most production is from shallow layers via gas oil gravity drainage. Waterflooding is planned to tap the large remaining reserves from deeper layers. Waterfloods in potentially fractured reservoirs is challenging and an accurate subsurface model is critical for success. 3D seismic covering the Fahud Jebel (acquired in 1994) is noisy over the crest of the field due to acquisition problems associated with gaps in coverage, coarse sampling, and absorption/scattering of energy in the weathered near surface layers.
An integrated project team covering acquisition, processing, interpretation, and reservoir geophysics was set up in 2002 to
justify, plan, and execute a new 3D survey
. A 2003 field pilot was executed to evaluate source & receiver coupling, lateral
sampling, and statics control requirements. The pilot concluded that
Vibroseis
data quality is generally better than dynamite
data, receiver coupling is not a limitation, and that the critical factor for data quality is source & receiver sampling and good
statics control.
The 2004 3D seismic survey
resulted in a nominal coverage at target that is 16 times higher than the 1994 acquisition. The
key success factors for operational and HSE goals were early planning, Digital Elevation Maps of the Jebel, and the use of
professional mountaineers. Preliminary results indicate that the new seismic data is superior to the 1994 data, particularly
under the Jebel.