Abstract
The Foinaven, Loyal and Schiehallion fields lie West of Shetland, some 170 Km west of Sullom Voe. These fields, operated by BP, consist of a number of channelised sandstone reservoir sequences of Paleocene age. They have been developed by high angle/horizontal production and injector wells, the placement of which is critical to the effective drainage of the reservoirs. The reservoirs have significant compartmentalisation due to a number of faults and facies boundaries which means that formation pressure data, coupled with other surveillance information, are critical in ensuring correct well placement. Additionally, formation pressures are required by completion engineers to determine completion string geometry. Until recently, the only available method for acquiring these formation pressures was to run a wireline tester on drillpipe, after the well had been drilled. As all other FE logs were generally acquired using LWD this was time consuming and expensive on the new generation rigs required to drill in this area. In 2004, the first pressure testing LWD tools were deployed in these fields, allowing formation pressure data to be acquired as part of the drilling process, thus allowing real-time decisions relating to wellbore trajectory to be taken, and eliminating additional pipe conveyed wireline runs. This paper discusses the process which was used to validate the measurements, quality control of the real time and memory data, and examines some of the advantages and disadvantages of acquiring formation pressure measurement as the well is drilled rather than after reaching TD.
