Print this pagePiper Plays a Different Tune
HARKER, STUART D and MARTIN BEDROCK
An increase of 62 MMBO (6.5%) in recoverable reserves has resulted from the redevelopment of the Piper Field (LJK North Sea Block 15/17) following the loss of the Piper Alpha platform in July 1988. The Piper field comprises four gently folded, tilted fault blocks on the northern margin of the Witch Ground Graben. The productive Oxfordian to Kimmeridgian age, paralic to shallow marine sandstones of the Sgiath and Piper formations are of excellent reservoir quality, with porosities of 18-30% and permeabilities of 200 - 10,000 millidarcies.
The Piper Bravo platform was installed in 1993 and improved recovery resulted from the optimized location and completion of 12 production and 4 injection wells (half that of Piper Alpha), assisted by the acquisition of a new 3D seismic survey in 1992. The optimization process proceeded by integrating old well data with new well information of cores, logs, pressures and fluid distribution. The new wells proved that beneficial redistribution of oil and water occurred during the 4.5 years that production was shutdown. The understanding of permeability repartition and control of sweep helped to significantly increase the production rate over the 1988 projected decline and achieve a markedly lower water cut. The current estimate for Piper ultimate recovery is 1014 MMBO (73.4%).