Welding the Maui A-B pipeline

Journal Article · Mon Nov 01 04:00:00 EST 1993 · Welding Journal (Miami); (United States)

OSTI ID:5864239

Butler, P ^[1]; Emmerson, J G ^[2]; Berg, Van Den R ^[3]

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1. Keerema Engineering Service, Ltd., London (United Kingdom)
2. Magnatech, East Granby, CN (United States)
3. DMB, Leiden (Netherlands)

Submarine pipelines have been installed all over the world, in diameters ranging from 76 mm (3 in.) up to 1270 mm (50 in.) or more and in water depths up to 500 m (1600 ft) using the S-lay method. In the 1950s, the J-lay concept was developed. With the J-lay technique, the pipe is suspended near vertically from the lay barge, thus reducing the horizontal force required to prevent pipe buckling. The J-lay technique has obvious advantages for deep-water applications where it is possible to eliminate the use of anchors by using dynamic positioning. The main drawback of the J-lay technique is that the near vertical pipe is difficult to handle and multiple workstations cannot be used. Only one length of pipe can be welded onto the pipeline at a time and subsequent inspection and coating must be done before the next weld can be made, resulting in low production rates compared to that achieved by S-lay barges. In 1989, Heerema, A Dutch company, which operates a fleet of semi-submersible crane vessels (SSCV) used for the installation of offshore oil and gas production platforms, decided to diversify into marine pipe laying. Realizing direct competition with established pipe lay contractors using S-lay barges could not be commercially competitive, an innovative J-lay system was designed which took advantage of the unique capabilities of the SSCV. Although the J-lay concept was some 30 years old, no functional system had been constructed as there was no immediate market for it, especially one which could justify inferior productivity when compared to S-lay barges. Heerema's solution to this limitation was to maximize the length of each piece of pipe added to the pipeline. By fabricating the pipe on shore into lengths up to 72 m (240 ft) and using the massive crane capacity (4000 tons) of the SSCV to lift each pipe string into position for welding, they could compensate for a lower productivity rate.

• OSTI ID: 5864239
• Journal Information: Welding Journal (Miami); (United States), Journal Name: Welding Journal (Miami); (United States) Vol. 72:11; ISSN 0043-2296; ISSN WEJUA3
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
022000* -- Petroleum-- Transport
Handling
& Storage
03 NATURAL GAS
032000 -- Natural Gas-- Transport
Handling
& Storage
42 ENGINEERING
423000 -- Engineering-- Marine Engineering-- (1980-)
AUSTRALASIA
DEVELOPED COUNTRIES
ENERGY SOURCES
FABRICATION
FLUIDS
FOSSIL FUELS
FUEL GAS
FUELS
GAS FUELS
GASES
INSTALLATION
JOINING
MATERIALS TESTING
NATURAL GAS
NEW ZEALAND
NONDESTRUCTIVE TESTING
OFFSHORE PLATFORMS
PETROLEUM
PIPELINES
PIPES
SEAS
SURFACE WATERS
TASMAN SEA
TESTING
TRANSPORT
WELDING