The Alba Field Obc Seisnic Survey

In early 1998, Chevron acquired one of the world’s first full-field four-component ocean bottom cable surveys at the Alba<br>field in the central UK North Sea. The primary objective of the survey was to use converted shear waves to image the top<br>of the reservoir and internal shales within the reservoir interval. The secondary objective was to map water movement in<br>the reservoir after four years of production and water injection by comparing the P-wave OBC data with the original 1989<br>streamer data. Our initial interpretation shows that both objectives were achieved with dramatic results – the converted<br>shear wave images provide the clearest image of the Alba reservoir sands ever seen and production effects are obvious<br>on the new P-wave OBC data.