Subsea/Surface Systems

While offshore applications of expandable tubulars have been successful, Enventure Global Technology continues to perform field trials of this new technology onshore where they can build experience and confidence before moving the technology out of the site of land. To this end, Enventure recently installed three expandable cased-hole liners in a well for Occidental Permian in West Texas.

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Seventh expandable tubular installed

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Enventure recently installed three expandable cased-hole liners in a well for Occidental Permian in West Texas. The liners were used to restore a 51-year-old plug and abandonment candidate to an injector well.
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While offshore applications of expandable tubulars have been successful, Enventure Global Technology continues to perform field trials of this new technology onshore where they can build experience and confidence before moving the technology out of the site of land. To this end, Enventure recently installed three expandable cased-hole liners in a well for Occidental Permian in West Texas. - Enventure recently installed three expandable cased-hole liners in a well for Occidental Permian in West Texas. The Enventure recently installed three expandable cased-hole liners in a well for Occidental Permian in West Texas. The liners were used to restore a 51-year-old plug and abandonment candidate to an injector well.

The liners were used to restore a 51-year-old plug and abandonment candidate to an injector well. The three expandable liner systems included one which was the longest expandable cased-hole liner ever installed. The three expandable cased-hole liners were installed at critical sections in the wellbore. The expandable liners used in each application interval were configured with the same basic components, varying in length from about 200 ft to 900 ft. Each liner was made of 4 1/4-in. 10.7 ppf casing with a series of elastomer seals at each end, which served both as a seal and as an anchor for the expanded liner.

The original production casing was 5 1/2 in., comprised of several weights. Prior to installing the liners, the casing condition throughout the five-decade old well, including OD and ID, was mapped using a Halliburton CAST-V ultrasonic log. Then the three 4 1/4-in-expandable-to-5 1/2 in cased-hole liners were installed to secure sealing integrity inside the in-situ 5 1/2-in casing.

Working from the bottom of the cased wellbore to the top, the first installation was deployed as the well's new packer seat, positioned below the two upper casing repairs. This installation interval was from a depth of 4,835 ft to 4,640 ft. The second installation, positioned from 3,773 ft to 3,236 ft, sealed 537 ft of deteriorated casing. The third, record length, cased-hole liner, was installed to repair the casing damage due to the corrosive clay formation. This cladded interval, from 910 ft to 1,824 ft (914 ft), was pressure tested to 880 psi. The upper liner system was also tested to 880 psi. The packer seat was tested to 2,000 psi. All three had zero leak-off. Post-expansion ID of the 4 1/4-in. expandable liner was 4.349 in. (compared to a pre-expansion figure of 3.750 in.).

While offshore use of this system is in its infancy, this application brings to seven the total number of solid expandable tubular installations completed by Enventure. Four of these were expandable cased-hole liner systems and three were expandable open-hole liner systems.

Coflexip Stena sets depth record for flex pipe

Working for Petrobras on the Roncador Field offshore Brazil, Coflexip Stena Offshore announced it has set a record for flexible pipe. The pipelay vessel Sunrise 2000 successfully installed a second 6-in. flowline in 6,178-ft water depth. While installing the first flowline in April, Coflexip set the standing world depth record at 6,036 ft. This second flowline, with a total length of 9.5 km beat that record by 142 ft. and connected RO-8 wellhead at 6,178 ft, to the P36 platform in 4,462-ft water depth. The two flowlines were designed, qualified, and manufactured by Brasflex and Flexibras, Brazilian entities of the CSO Group.

Plans for Nakika include semi hull

Despite contrary reports, the Nakika field in the Gulf of Mexico will not be a Spar-based development. The most likely solution will be a permanently moored production system in the shape of a semisubmersible hull. Shell Offshore is moving toward sanctioning a production solution for Nakika development in Block 474 of Mississippi Canyon. Nakika will act as a hub for a number of smaller fields discovered in the surrounding area.

The hub will accept production from at least 10 wells located on at least five fields. From the platform, Nakika will transport production to on-shelf platforms. The production pipelines will be attached to the Nakika platform by steel catenary risers. This solution is currently undergoing final economic analysis and should be sanctioned in September. Nakika will be installed in about 6,000-ft water depths. Once approved, Nakika will be the deepest development system in the Gulf of Mexico.

CRP builds subsea arch and risers

Working for Stolt Offshore on the Soekor-Oryx field offshore South Africa, CRP Marine built a subsea arch with 40 tons of buoyancy to support the risers for the field. The two risers link two wells to an existing FPS in shallow water (387 ft). The risers are subject to complex currents and there was insufficient depth for the pipe layout. CRP used composite foam buoyancy modules supported in a steel framework rather than a traditional all-steel structure.

Dry trees in deepwater

PGS Offshore Technology has designed a deepwater production semisubmersible that uses dry trees in order to reduce development costs. The platform would use taut leg mooring and a riser support tower that can be jacked up above the waterline for transport, then lowered to protect the risers. Buoyancy cans positioned mainly on the lower part of the riser support tower will support the dry completion risers. These will connect to dry trees on the deck. The DTS-P design also features a workover rig for maintenance of the wells.

Designed to compete with other dry tree solutions such as the Spar and tension-leg platform, PGS contends the wellhead platform would be less expensive to construct because it is based on a conventional semisubmersible design. It does not require any offshore heavy lifts or mating as a Spar does, or any of the complex foundation and tendon installation work required for a TLP. PGS said the DTS-P has undergone basic engineering to the class drawing level.

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