Complex reservoir de-risking using advanced pre stack depth migration technology

The North Sea is a mature basin where it is increasingly challenging to make new and economically viable discoveries. Even after discoveries have been made, it is vitally important to have high confidence in the reservoir’s extent and spatial location before committing to a development plan. Here we detail the case history of a multi-azimuth pre-stack depth migration re-processing and re-imaging project over the Oda (formerly Butch) discovery in the Norwegian sector of the North Sea. The Oda structure is a complex salt diapir making it crucial to have as much confidence as possible in the position of the reservoir before making a drilling commitment. This study documents how the use of the latest imaging technologies, which include source and receiver deghosting, multi-azimuth full waveform inversion, multi-layer tomography and tomographic uncertainty analysis can aid in de-risking and improving reservoir definition, thereby increasing confidence in development well planning.