Subsea pipeline gets welded branch without halting flow

Journal Article · Mon Dec 11 04:00:00 EST 1995 · Oil and Gas Journal

OSTI ID:136995

West, A; Hutt, G ^[1]; Starsmore, R ^[2]

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1. Stolt Comex Seaway Ltd., Aberdeen (United Kingdom)
2. Wintershall Noordzee B.V., Den Helder (Netherlands)

In October 1994, a 16 in. welded branch was installed without interruption to production onto Wintershall Noordzee BV`s 36-in. gas pipeline from the K13-A platform in the Dutch sector of the North Sea to Den helder, The Netherlands. The procedure is the first successfully to combine hyperbaric welding and subsea hot tapping without interruption to production. Developers of new fields can now consider exporting product without interrupting existing production and through existing infrastructure even if no convenient tie-in locations exist. Unocal evaluated export options and established that the most attractive alternative was to export gas into the Wintershall 36-in. K13-A to Den Helder pipeline. Various options for installing a branch included the following: flooding the pipeline and installing a conventional tee; stopping production and installing a welded branch followed by hot tapping; and continuing production and installing a welded branch followed by hot tapping. The chosen scheme was to retrofit a subsea side-tap assembly. This was achieved by installation of a welded branch followed by hot tapping into the 36-in. pipeline. The paper describes location determination, schedules, onshore preparation, and offshore work.

• OSTI ID: 136995
• Journal Information: Oil and Gas Journal, Journal Name: Oil and Gas Journal Journal Issue: 50 Vol. 93; ISSN 0030-1388; ISSN OIGJAV
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
DESIGN
MITIGATION
MODIFICATIONS
NATURAL GAS
NETHERLANDS
NORTH SEA
PIPE JOINTS
PIPELINES
RETROFITTING
SUPPLY DISRUPTION
TRANSPORT
WELDED JOINTS