The development plan for the gas field involved the construction of a 500 km, 26 inch pipeline from the field to Wickham Point, Darwin, where a new LNG facility has been constructed. Multiplex and Saipem SpA built the pipeline from Bayu-Undan to shore at a cost of $A500 million, while Bechtel was responsible for the construction of the LNG plant.

From this new facility, Australia’s second dedicated LNG export centre, Bayu-Undan gas will be shipped to a variety of locations, including Japan, where buyers including Tokyo Electric Power Company and Tokyo Gas have signed on to purchase gas from the development.

In the past six months, the project has proceeded rapidly towards conclusion. Last October, first gas was extracted from the Bayu-Undan to Darwin pipeline for commissioning of the LNG plant, and first production of LNG from the project is expected in a matter of months.

A new facet to the project has also developed through the latter stages of 2005 with the discovery of a new gas field, Caldita, offshore the Northern Territory. Santos has since said it will look to expand the Wickham Point LNG plant, with the construction of a second plant, which would be a carbon copy of the first, being considered.

As the initial Bayu-Undan project moves towards completion, and plans are made for further development in the vicinity, it is therefore appropriate to take a closer look at the work that went into delivering this project. Furmanite has been engaged in a number of contracts on the project and have shared their experiences with The Australian Pipeliner.

Integrity Management

A pressurised systems integrity management service from Furmanite was selected by Bechtel Corporation in the construction of the Wickham Point LNG plant. The integrity management service enabled critical joint bolting and machining work to be undertaken with an assurance of no delays thanks to a leak-free start-up guarantee.

Furmanite was appointed to work on the construction project on the basis of its proven experience, reliability and quality of work on projects of a similar stature. Furmanite is providing its Pressurised Systems Integrity (PSI) Management services, involving joint inspection, gasket installation and controlled bolting of flanged joints on the plant (with bolt sizes from 1.25 to 3.5 inches), including supervision of Bechtel technicians, provision of specialist tools and equipment, and full documentation.

Under the contract, Furmanite worked on 290 raised face ANSI flanged joints on lines connected to the offshore main gas line, ranging in size from 15 through 54 inches with an operating pressure of 190 bar. At the time of printing, Furmanite was due to complete this contract at the end of 2005.

Furmanite’s PSI Management service is designed to eliminate critical joint failure to deliver an on-schedule zero-leak start-up by addressing all factors known to cause leaking joints. Among the key benefits are avoidance of costly delays, reduced equipment and testing costs and need for re-work, and earlier demobilisation of labour. Whether applied within a new-build or scheduled maintenance program, the service drives down costs and removes risk.

Typically, flange distortion, sealing surface damage, incorrect bolt loads and uncontrolled tightening methods are among the primary causes of leaking flanged joints. Furmanite’s service addresses these by inspecting all joints, machining any damaged pipe and flange faces undertaken to ensure a positive seal when the flange is bolted, and tightening the bolts to the required preload using hydraulic tensioning.

The full service also involves logging all data relating to each joint into the PSI Management system, which is bespoke software, held and managed by Furmanite and requiring no purchase by the client. The software offers real-time reporting including all mechanical and work data for each joint.

This is accessible to both the Furmanite site manager and also the customer, who can access the system remotely via the internet with a secure passcode entry system, providing a full, user-friendly overview of workscope status and progress. As work proceeds, a detailed history of each joint is built up to create a comprehensive, easily accessed record for full traceability and assistance in future maintenance planning.

Ensuring leak-free joints is not simply a matter of tightening the bolts, and requires specialist skills and experience, hence the importance of Furmanite’s supervision of Bechtel’s technicians as part of the contract.

Furmanite sales manager David Arnold said “Knowing that the penalties for overrunning on this project are high, the fact that our service is designed to deliver a leak-free start, avoiding any expensive delays, was a critical factor to Bechtel. Work is now underway and we will be on-site for eight months to undertake this project.”

Specialist expertise removes hazard risk in major gas rig shutdown

Specialist equipment and expertise enabled Furmanite to undertake on-site machining work, including some specialist requirements on the Bayu-Undan platform during a shutdown last year with optimum speed, accuracy and safety.

The size and scope of the shutdown on the platform is reported to have been one of the world’s largest. Within the extensive workscope, Furmanite was called in to undertake a range of hot tapping and on-site machining work, including machining heavy pipe wall and exotic materials. Cold cutting techniques were used throughout, as hot cutting presented an unacceptable risk in the given environment.

Among the specialist machining requirements, Furmanite’s role included undertaking a 12 inch hot tap into a 20 inch diameter stainless steel flareline, as well as a 10 inch diameter hot tap into a heavy wall caisson for positive isolation to enable the inner caisson overflow level to be modified.

In addition, Furmanite undertook pipe cutting and weld prepping to various pipework – including heavy wall, up to 30 inch diameter pipes, using rotary cutting technology. Removal of small bore pipework and support brackets was also completed, as was flange facing of several damaged flange faces. This ensured an effective seal for joint integrity and ring type joint (RTJ) modification to raised face joints on the export line for temporary use at a reduced pressure rating for dewatering.

To undertake all pipe cutting, weld prepping, hot tapping and flange facing work Furmanite used its specialist pneumatically-driven cold cut machining equipment. This virtually negates the risks associated with hot cutting, while also offering efficient, accurate cut and prep facilitation to minimise welding time and re-work that can occur from impurities remaining in the cut area from hot cutting.

The flange facing work was undertaken using lightweight, portable machines which were set up on the work piece in-situ, avoiding costly and hazardous removal for machining in the workshop and re-welding to reinstall afterwards. Air-driven cold cut power saws (also light in weight and able to be used in areas of constricted access along the pipe racking) were used to remove the small bore pipework and support brackets. The hot tapping work was undertaken using specialist hot tap machines designed for live work on pipelines.

Highly skilled Furmanite technicians undertook the work, which was completed over a six week period.

Commenting on the work, Amec integrated shutdown team manager Dave Gray said “We were extremely pleased with the high standard of work. Furmanite’s industry experience and expertise enabled them to undertake the full scope efficiently, within the scheduled timeframe.”