Expandable tubulars have now been deployed using corrosion-resistant alloys to increase the diameter of the production conduit and to shut off corroded and partially collapsed perforations.

The US Department of Energy reported that more than 70% of the country's natural gas comes from wells deeper than 5,000 ft (1,525 m). If America's demand for clean-burning natural gas increases, operators will have to drill to depths of 15,000 ft (4,575 m) or more to tap the estimated 125 Tcf of natural gas trapped there. The high-pressure, high-temperature environments of such wells will require new tubulars for drilling. Enventure Global Technology recently developed the ability to use its game-changing Solid Expandable Tubular (SET) technology to expand the corrosion-resistant 13% chrome (13Cr) tubulars that will be necessary to drill that deep even in highly corrosive environments.
Enventure successfully installed the world's first corrosion-resistant alloy (CRA) SET System in a well located in the Netherlands for NAM, Western Europe's largest natural gas producer. The cooperative efforts of Shell International E&P, NAM, Vallourec Mannesmann and Enventure resulted in the expansion of a 6-in. 13Cr cased-hole liner inside 75/8-in. casing. Gas-tight, CRA expandable connections and tubulars, jointly developed by Shell and Vallourec Mannesmann, also were used for the first time in this extraordinary SET system installation.
"This is one of the biggest step changes the oil and gas industry has undergone in 40 years," said Hans Bouman, Groningen asset manager for NAM. "The increased durability of Cr13 tubulars in corrosive environments will dramatically reduce the limitations on how deep we can drill."
The 710-ft (217-m) CRA cased-hole system, installed in a gas well in the Wanneperveen field, was expanded in 75/8-in. 39 lb/ft, 33.7 lb/ft and 29.7 lb/ft casing, with elastomer seals in each section. About 92,000 lb of combined mechanical and hydraulic forces were used to expand the chrome pipe by 9.8%. Post-expansion ID of the18.6 lb/ft CRA liner was 5.92 in., compared to a pre-expansion diameter of 5.39 in. Post-expansion burst and collapse were estimated at 7,000 psi and 4,000 psi, respectively. Overall liner length was reduced from 730 ft (223 m) to 710 ft (217 m) as a natural result of the expansion process.
"This proof of concept test is in preparation for the installation of a 5,500-ft (1,678-m) expandable CRA system to re-line production casing so it can be used as the production conduit," said Lance Cook, president and chief executive officer of Enventure. "The ability to expand 13Cr tubulars will allow far greater production deliverability from highly corrosive wells."
Production diameter enlarged by 14%
Enventure also collaborated with Sarawak Shell Berhad and Petronas Carigali to install a record-length SET system in an offshore gas well located off the coast of Sarawak, Malaysia. A 4,504-ft (1,374-m) length of 75/8-in. expandable cased-hole liner was installed successfully inside 95/8-in. casing, then expanded to an outer diameter of 8.54 in. to replace the existing tubing with a larger production conduit.
The project also resulted in four other important "firsts," including:
• first SET application used to increase production in tubing-constrained gas wells;
• first SET technology application in the Asia region;
• first SET to utilize a wireline-retrievable plug; and
• Shell's first cased-hole liner.
Smedvig's West Pelaut rig was used to run the 4,504 ft (1,374 m) of 75/8-in. expandable liner into the 95/8-in. 43.5 lb/ft casing to a setting depth of about 5,000 ft (1,525 m). The system was expanded using propagation pressures of nearly 2,100 psi, then pressure tested at 1,600 psi for 15 minutes per operator and regulatory requirements. Post-expansion ID of the liner was 7.8 in., compared to a pre-expansion diameter of 6.2 in., dramatically increasing the deliverability of this gas reservoir. Post-expansion yield and collapse were estimated at 5,850 psi and 2,560 psi, respectively. The 29.7 lb/ft liner expanded 13.9% while exhibiting a 4.36% reduction in overall length.
This installation was also the first to use a wireline retrievable plug to pressure against for expansion rather than having to drill out a shoe. In a standard system the plugging device is on the bottom of the liner and has to be drilled out and is non-retrievable.
"This achievement firmly establishes Shell as the leading SET technology trailblazer in Asia and the world," said Edmund Huang, central asset manager for Sarawak Shell. "Enventure's SET system, together with Shell expertise, delivers expanded production, expanded value and expanded opportunities for all our partners and stakeholders. This technology is changing the industry, and we are committed to accelerating the development and application of solid expandable tubular technology to Shell wells worldwide."

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