Space weather services for the offshore drilling industry

The requirement to extract the maximum amount of oil from reservoirs while continually striving to reduce drilling costs has led to the development of the technique of directional drilling over the last few decades. The oil industry now has the capability to drill dozens of wells from a single platform in many different directions, extending typically to 5km horizontally. The world record for extended reach drilling is in excess of 11km. The size of the geological targets requires an accuracy in direction of the order of 0.1 degrees in navigating the well-bore. Surveys of this accuracy can be made using gyroscopic instruments, but these require drilling to stop for the duration of the survey, which may be some hours. When the cost of the rig hire is taken into account it makes these surveys expensive to conduct. A cheaper method is to use magnetic survey instruments in a non-magnetic part of the drill string near the drill bit. These can make measurements while drilling, but the accuracy is limited by the accuracy with which the direction of the Earth's magnetic field is known. In the North Sea this may typically change by up to 0.2 degrees throughout the day, and during magnetic storms deviations of the order of a few degrees may be experienced. The British Geological Survey has developed the technique of Interpolated In-Field Referencing (IIFR) to remove this source of error by using data from its magnetic observatories. Data are required by the well-bore surveyors in near-real time when decisions have to be made about steering the well. The benefit to the oil industry of using IIFR derives from the fact that an accuracy similar to that achieved with gyroscopic survey tools can be achieved with magnetic survey tools. This means that wells can be drilled with fewer or no gyro surveys, greatly reducing the costs associated with navigating the well-bore. Additionally there are fewer risks to drilling operations than when running gyroscopic tools because the long pauses in drilling required by the gyro surveys may lead to the drill string getting stuck in the hole. As a space weather service, IIFR can be characterized primarily as a near real-time monitoring service. Forecasting does not play, and is not likely to play, a significant role because no decisions are made affecting drilling operations based on a space weather forecast. IIFR has been applied in more than 30 offshore oilfields around the UK, and has been applied in other high latitude oilfields offshore Canada and the USA. It is unlikely that the benefits would be significant at geomagnetic latitudes much lower than the North Sea