The first 3D/4-C ocean bottom seismic surveys in the Caspian Sea: Acquisition design and processing strategy

摘要

Bubbling mud volcanoes create havoc for conventional seismic images over the crest of the Azeri-Chirag-Gunashli (ACG) structure in the Caspian Sea. Layers of trapped gas and shallow mud flows in the overburden sediments leave areas of severely degraded data quality at the crest of the reservoir structure. Fortunately, in 2002, the application of the first 3D four-component (3D/ 4-C) seismic in the Caspian has helped lift the veil of mud and gas attenuation which previously obscured the details of the subsurface reservoir. Application of closely coupled innovations in both acquisition and processing have now delivered exceptional improvements in data quality, particularly in the case of the P-wave images, which have significantly reduced structural uncertainty in both the critical, high well density, central Azeri area, and the undeveloped Gunashli portion of the structure. Armed with an improved image of these reservoirs, the ACG team is poised to accelerate production by avoiding both unplanned well sidetracks and expensive pilot holes.