f Use of walkaway VSP in imaging a pre-zechstein reservoir in the UK Southern Gas Basin

The results of many VSPs are disappointing because they have not been planned in detail, and processing has not been optimised to achieve the prime objectives due to lack of communication between the specialists involved in planning, acquiring, processing and interpreting the data. In the case study reported here the close co-operation between interpreter, technical advisor and VSP processing geophysicist resulted in a carefully designed survey and an optimised processing sequence which fulfilled the planned objective and yielded further information.