This is the first time on the Norwegian continental shelf, and only the second time in the world, that the PowerDrive drilling tool from Schlumberger has been used in conjunction with a mud motor. It took the Transocean Winner just three and a half days to drill a 12-1/4 inch section to the top of the reservoir on the Asgard field. Normally it would take seven and a half days to drill the 7,053 foot section. The day rate for drilling operations on the rig is around NOK 2 million.
A motor was included to achieve a higher rate of penetration (ROP). When directional changes are made with the motor during conventional drilling, ROP is a quarter of that achieved with the new system.
The production well was drilled on Smorbukk, which is a hard, deep, high temperature structure.
"Not only do drilling operations take less time with the new system, it can also be used for more technically challenging wells," reports Rune Skotvold, lead drilling engineer in Asgard resource development. He believes that rotary steerable drilling combined with mud motor may be the future on Asgard, but adds that needs vary a great deal from one field to another. The system is best suited to the most demanding fields, says Mr Skotvold.
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