Parker Drilling Co.`s Rig 257 is on its way to the Northeast Caspian Sea, where it will begin a drilling program on the Kashagan East prospect for Offshore Kazakhstan International Operating Co. NV. Photo courtesy of Parker Drilling.
A newly upgraded arctic barge rig owned by Parker Drilling Co., Tulsa, is on its way to the Caspian Sea to begin a drilling program for Offshore Kazakhstan International Operating Co. NV (Okioc).
Rig 257 departed Astrakhan, Russia, July 7 and is under tow to the Northeast Caspian, where it will begin work in August under long-term contract to Okioc.
Christened "Sunkar" by a member of the Kazakh parliament, the rig has just undergone a major modification project that Parker said converted it to "the world`s largest barge rig capable of drilling in the harsh environment of the Caspian Sea."
The first well to be drilled with the rig will be on Okioc`s Kashagan East prospect, about 75 km south of Atyrau, Kazakhstan. Drilling is expected to take 4 months and will be followed by testing.
Okioc is comprised of Agip SpA, BG International, BP Amoco plc, Inpex, Mobil Corp., Phillips Petroleum Co., Royal Dutch/Shell, and TotalFina SA. The Kashagan structure is one of several prospects identified by the consortium following a seismic survey conducted during 1993-97.
After the survey was completed, Okioc negotiated a production-sharing agreement with the Kazakh government for exploration and production work in a 6,000 sq mile area containing the Kashagan prospect.
The upgrade
The rig is operated under contract with Parker Drilling Co. International Ltd. It has been extensively modified to enable it to operate in the harsh conditions of the Northeast Caspian Sea, says Parker Drilling. The rig modifications were made at Astrakhan.
The rig is able to handle shallow-water, open-sea conditions; extreme temperature fluctuations; ice forces; difficult geology; and the expected presence of hydrogen sulfide. Its hull is 277 ft long by 173 ft wide by 18 ft deep and is equipped with 14-ft ice deflectors.
Rig 257 has a maximum drill-floor load and a maximum hook load of 1.3 million lb each. It has a 3,000-hp draw works, rated to 30,000 ft, and a 650-ton top drive, rated at 5,000 psi working pressure.
The rig is equipped with three triplex pumps, rated at 1,600-hp each, and four linear-motion shale shakers.
Given the harsh climates in which the rig will operate, Parker outfitted it with special life-saving equipment.
It will carry three 50-person all-terrain vehicles and eight 25-person inflatable rafts.
Parker Pres. and CEO Bob Parker Jr. said, "Rig 257 is the most technically sophisticated rig in our fleet and is the only arctic-class barge rig in the world. The rig and project form a strategic part of our business plan to be the dominant drilling company in theellipseNorth Caspian Sea region."
Environmental issues
The Kashagan exploration area lies in a nature preserve, so Okioc must meet strict environmental regulations. The rig cannot discharge drilling wastes into the Caspian, for instance.
"Many environmental protection systems have been integrated into the rig design," said Parker Drilling. "(The design) is based on 5 years of study and research in the Northeast Caspian Sea environment by a team of Kazakh, Russian, and international scientists.
"Drilling mud will be recycled or taken by barge to the company`s (Okioc`s) marine supply base at Bautino (Kazakhstan). All cuttings removed during drilling operations will be taken to Bautino by barge to a state-of-the-art treatment plant."
Drilling operations will be supported by two icebreaker supply boats and three tugboats. These boats also were designed and built for the shallow-water and ice conditions of the region.
