Development of Acquisition Methodologies and Technologies in the North Caspian Sea Seismic Exploration

From 1994 until present days, North Caspian Sea seismic acquisition methodologies and equipment have changed dramatically. In addition the offshore operations have increased the complexity of the seismic exploration activity. This Paper gives an excursus of the seismic acquisitions carried out by KazakhstanCaspiShelf (KCS) Consortium and by Agip KCO from 1994 to 2007 over the Northern, shallow water sector with particular focus to the North Caspian Sea PSA contracted area of Kashagan. The 1994-1995 2D acquisitions, streamer and ocean bottom cables (OBM) allowed to identify zones of potential oil and gas accumulation within Kazakhstan sector of the Caspian Sea and its coast and to determine priority of oil and gas prospects for exploration and detailed seismic activities. The 2001-2002 3D seismic acquisition over Kashagan allowed the detailed pre and post salt structures mapping. The 2007 3D4C seismic acquisition test over a portion of the Kashagan structure allowed to obtain better interpretation of the pre and post salt layers and the gathering of data for reservoir characterization. The seismic acquisitions in the North Caspian Sea have benefited in the years the methods changes and technologies improvement to allow continuous improvement in the data gathering quality.