More on the new BP rig...
Liberty drilling rig enroute to Alaska
bp.com
Release date: 15 July 2009
The barge containing the Liberty drilling rig crosses under
the I-5 bridge between Portland, Ore., and Vancouver, Wash.
A barge containing a specially designed drilling rig that will be used by BP Alaska to tap its offshore Liberty field is in-tow to Alaska, and is expected to reach its drilling site in the Beaufort Sea by late July during the Arctic’s brief open-water season.
The Liberty field was discovered in 1997. Located about 15 miles east of Prudhoe Bay on federal offshore waters, the field contains an estimated 100 million barrels of recoverable oil. Development costs are estimated at about $1.5 billion. Drilling will commence in 2010 and first oil is expected a year later, with production ramping up to 40,000 barrels per day.
The development plan calls for up to six wells that will be drilled from Endicott’s Satellite Drilling Island, or SDI, that was enlarged to accommodate the rig, wells, manifolds and other ancillary facilities.
In order to develop the offshore Liberty field, BP Alaska commissioned Parker Drilling Company in 2007 to build a powerful, ultra-extended-reach top-drive drill rig that could drill ultra-extended-reach wells with a horizontal departure of six to eight miles. To handle such a long drill string, Parker built what has been characterized as the world’s most powerful onshore drill rig.
To handle the exceptional demands of rotating and moving a drill string in a well bore that may be up to eight miles long, the rig has to be able to apply an exceptionally high turning force to the drill pipe. Consequently, a key component in the new rig will be the massive top drive, the device slung in the rig derrick to grip and rotate the drill pipe.
The drive will apply 105,000 foot-pounds of torque to the drill pipe while rotating the pipe at 130 revolutions per minute. In a typical North Slope rig, the top drive will provide torque in the range of 30,000 to 45,000 foot-pounds. In fact the power of the drive is the highest rated on any drill rig worldwide.
“This piece of equipment delivers more than two times the power requirement to turn the drill pipe as any other piece of equipment used on the North Slope,” says Darryl Luoma, BP Alaska’s Liberty project general manager.
BP Alaska is developing specially designed drill pipe that is relatively lightweight but can withstand the high torques that the top drive will be able to deliver.
Because a single well might require 90,000 to 100,000 feet of drill pipe and casing, the new rig layout will include an especially large pipe barn. Equipment to automatically handle the assembly and positioning of the drill pipe will enhance rig safety, Luoma adds.
“People won’t have to physically screw the pipe lengths together,” he adds. “There is equipment that picks it up, puts it together and then lifts onto the drilling rig floor.”
The long wells will also require fluid pressures up to 7,500 pounds per square inch, compared with the 3,500 to 4,500 pounds per square inch of a typical Prudhoe Bay drilling operation. And the volumes of fluid involved require an especially large drilling service module for fluid handling.
Powered by natural gas, the rig will be outfitted for Arctic conditions, including low-temperature tolerant steel, and thermal sound dampening insulation. It is equipped with a Amphion integrated control system which provides centralized monitoring, command and management systems. The rig will operate with a crew of 84 people (42 day / 42 night).
BP has drilled some of the longest extended-reach wells in industry at its Wytch Farm oil field in the United Kingdom, where 35,000-foot departure wells have been completed.
Extended-reach wells up to 21,707 foot departure and 26,090 feet measured depth have also been drilled by BP on the North Slope to tap its Niakuk and Northstar developments. |
