The Systematic Application of 4D In BP's North West Europe Operations - 5 Years On Available to Purchase

Since 1999, BP has carried out a vigorous 4D program in the North Sea. Early progress with this was reported by Whitcombe et al. (2001). Up to that time, 4D had been applied to the technically easier Tertiary sandstone targets in the West of Shetland and Central N Sea. Since then it has been applied to both older reservoirs, such as Magnus (Jurassic), Marnock (Triassic), and Sean (Permian). Additionally it has been applied to compacting chalk reservoirs (e.g. Valhall) and to challenging high dip reservoirs located on the flanks of Central North Sea salt domes (e.g. Mungo and Machar). Interpretation of amplitude associated 4D signals has been both in the reflectivity and impedance domain, and 4D timing shifts have been exploited to observe pressure changes in thicker reservoirs. ‘Dynamic interpretation’ of the 4D data has been achieved by co-visualizing the seismic 4D and 3D elements with other dynamic (e.g. well production history, simulation output) and static (e.g. well log) information. This has led to the 4D data impacting field decisions, sometimes only days after its delivery. The confidence of dynamic interpretation has been enhanced by the use of multiple 4D vintages; for some fields West of Shetland, five repeat surveys are now available. Full integration of the dynamic interpretation with reservoir simulation has been carried out in several cases, and has greatly constrained the history matches and thus improved the quality of field performance predictions.