Staged Subsalt Derisking for Development of the Cleaver Bank High

For many years the west of 49/14b, offshore U.K. was poorly imaged due to a complex en-echelon system of salt ridges. These issues prevented the development of Carrack West. In 2006 a seismic survey with a different azimuth, and longer offset was acquired. During the first stages of the processing the interpretation started on the Post-STM. A Pre-STM was delivered together with a Kirchhoff Pre-SDM. The Kirchhoff Pre-SDM on the 2006 dataset was encouraging, it was also noted that the vintage seismic, shot under a different azimuth, showed more energy in certain areas and a dual azimuth processing was performed. At the same moment it was realized that the standard approach of single valued Kirchhoff did not cater for the complex ray-paths in parts of this setting. A WEM enabled us to improve the imaging even further. It is demonstrated that the 5 different datasets all have their own merits. The minute mapping that was needed for the development planning of the Carrack West discovery profited from the parallel use of all the products and only now we are confident on the risk level to take the development of the project further.