Formation Pressure Testing While Drilling for Deepwater Field Development

摘要

The Foinaven, Loyal and Schiehallion fields lie West ofShetland, some 170 Km west of Sullom Voe. These fields,operated by BP, consist of a number of channelised sandstonereservoir sequences of Paleocene age. They have beendeveloped by high angle/horizontal production and injectorwells, the placement of which is critical to the effectivedrainage of the reservoirs. The reservoirs have significantcompartmentalisation due to a number of faults and faciesboundaries which means that formation pressure data, coupledwith other surveillance information, are critical in ensuringcorrect well placement. Additionally, formation pressures arerequired by completion engineers to determine completionstring geometry. Until recently, the only available method foracquiring these formation pressures was to run a wirelinetester on drillpipe, after the well had been drilled. As all otherFE logs were generally acquired using LWD this was timeconsuming and expensive on the new generation rigs requiredto drill in this area. In 2004, the first pressure testing LWDtools were deployed in these fields, allowing formationpressure data to be acquired as part of the drilling process, thusallowing real-time decisions relating to wellbore trajectory tobe taken, and eliminating additional pipe conveyed wirelineruns. This paper discusses the process which was used tovalidate the measurements, quality control of the real time andmemory data, and examines some of the advantages anddisadvantages of acquiring formation pressure measurement asthe well is drilled rather than after reaching TD.