Hot-tap readies Statpipe for Gullfaks tie-in

Statoil AS's veteran North Sea gas trunkline, Statpipe, underwent a delicate hot-tap operation last week in preparation for the tie-in this autumn of the Norwegian state oil company's Gullfaks satellite Phase II export line. The successful hot-tap, only the second of its kind off Norway, was carried out in water depths of some 135m by divers from the Seaway Osprey support vessel operated by the Stolt Rockway joint venture.


LONDON�Statoil AS's veteran North Sea gas trunkline, Statpipe, underwent a delicate hot-tap operation last week in preparation for the tie-in this autumn of the Norwegian state oil company's Gullfaks satellite Phase II export line. The successful hot-tap, only the second of its kind off Norway, was carried out in water depths of some 135m by divers from the Seaway Osprey support vessel operated by the Stolt Rockway joint venture.

The hot-tap procedure involved drilling a 30 cm hole into Statpipe through a welded T joint outfitted with a shut-off valve without interrupting gas flow. The drill was then drawn back and the valve shut. Tie-in of the Gullfaks field's A and C platforms and pressure-testing will be required, noted Statoil, before the new connection goes live.

Gullfaks's 35 km export line was laid this summer running from the A installation to Statpipe and back to Gullfaks C in a loop.

Statoil said the Gullfaks tie-in would become increasingly important to the oil company as a gas exporter, with Gullfaks set to account for "more than half the gas reaching [the company's gas treatment complex at] Kårstø" through Statpipe.

Built to carry large gas volumes from Statoil's Statfjord, Gullfaks, and Heimdal developments, the Statpipe system, which came into operation in 1985, links a large clutch of the operator's northern North Sea fields to the European gas market. The construction of the trunkline is considered to have laid the groundwork for the extensive pipeline infrastructure currently being used for Norwegian gas exports.

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