STATS Group repairs subsea gas export pipeline in Thailand

The pipeline technology specialist was commissioned by CUEL Ltd to repair an 8 in. gas condensate export pipeline in the Gulf of Thailand, which had been dragged 8 m out of position by a vessel anchor and required a permanent repair.

STATS utilised its range of subsea products to facilitate the repair, which included BISEP’s, slab valves, hot tap fittings, completion plugs, end connectors and abandonment plugs – all engineered, manufactured, tested and deployed in-field – allowing a pipeline repair with no impact to production, the environment or risk to diver safety.

Working with CUEL and the pipeline owner, a repair methodology and solution was developed, whereby an 8 in. bypass was installed on the seabed as a permanent repair to reroute the pipeline medium away from the damaged pipeline section, which was situated at a water depth of approximately 60 m and had an operating pressure ranging from between 7 - 21 bar.

Mark Gault, Subsea and EPRS Product Line Manager for STATS Group, said: “This subsea pipeline repair project presented many operational and technical challenges. The successful completion demonstrates STATS’ ability to accommodate complex operations while maintaining high levels of safety at all times.

“STATS’ range of subsea isolation and intervention equipment provides operators a turnkey service for pipeline repair scenarios and establishes STATS’ capabilities within the subsea market. We will use the experience and our proven track record of first class delivery of these major projects to seek out other global opportunities for similar subsea contracts.”

STATS’ patented BISEP was selected to provide leak-tight isolation of the pressurised pipeline and was deployed through a full bore hot tap penetration at the isolation location through a mechanical hot tap fitting.

Gault added: “The DNV GL type approved BISEP provides a fully proved, fail-safe, double block and bleed (DBB) isolation barrier from the pressurised pipeline. This level of isolation complies with industry guidance on isolation and intervention for diver access to subsea systems, ensuring diver and worksite safety.

“The pipeline repair solution incorporated installing a permanent bypass pipeline, which allowed the operations to be completed without the need for shutting-in pipeline production or depressurising, thus, ensuring production was maintained uninterrupted.”

STATS has previously completed a subsea isolation on behalf of COOEC Subsea Technology when the Yacheng pipeline in the South China Sea – an important asset for suppling gas to Hong Kong – was severely damaged by a ship’s anchor. The pipeline was repaired at an unpiggable location 280 km from shore and in water depths of 60 m without depressurising and flooding the entire pipeline.

UK headquartered STATS Group is supported on Asian projects from its base in Kuala Lumpur and has engineering, design and storage facilities in Abu Dhabi and Qatar.