Cold cure for piping connections

March 3, 2012

There is growing interest in ‘cold based’ operations which dispense completely with the gases, ignition sources, flames and hot work associated with welding for piping repair construction, modification and tie-in work, especially on ageing offshore infrastructure. Quickflange CEO Rune Haddeland discusses recent applications of his company’s eponymous piping connection technology.

While most maintenance attention tends to concentrate on ‘critical application’ pipelines which deliver oil & gas from the reservoir to shore, operators today must also focus on the often complex network of piping systems that are prevalent on offshore platforms. Such piping systems support everything from fire fighting, cooling and water injection through to compressors and scrubbers.

Furthermore, as fields and platforms become that much older, so the challenges increase with piping repair construction, modification and tie-ins often having to take place around ageing and often interdependent infrastructure, where the threats of leaks and corrosion are high, and where activities often take place against the backdrop of continuing production.

cold cure

Some estimates suggest that as much as 20% of total investments in piping infrastructure over the next decade will be spent on maintaining and upgrading existing infrastructure.

With many platforms facing harsh and remote conditions aligned with regulatory, environmental and safety pressures, as well as the need to manage costs, maintaining topside piping integrity is a key issue for today’s operators.

So are today’s piping connection technologies addressing these challenges? For many piping managers and engineers, the prominent technology for ensuring piping connections and installing flanges is that of ‘hot-based’ welding where access to heat sources is required. Welding today, however, comes with a number of limitations.

First, there are the safety implications and regulatory requirements. With the need to test for flammable gases, the risk of fires from ignited materials, the importance of ensuring adequate ventilation, and the need to isolate areas of operation, welding can be a highly labour-intensive process. Permission to conduct hot work on site, for example, often requires up to two weeks’ advance notice and often necessitates a significant amount of paper work before people have even started to be mobilised and the first pipes cut.

In addition, while there may be occasions where a piping tie-in may be relocated onto a line that can be temporarily isolated, production shutdown is often the only option with welding, making it an even more expensive process.

With these issues in mind, there’s a growing demand for lower impact and more flexible piping connection solutions and for alternative engineering approaches to traditional piping connections on offshore platforms.

Cold solutions

The last few years have seen a growing interest in ‘cold based’ operations which dispense completely with the gases, ignition sources, flames and hot work associated with welding, but are still able to provide a highly secure and leak-free mechanical and pressure-tight connection. The result is safer and more secure operations with no fire or explosion hazards.

The ‘Quickflange’ solution (Figure 1 above), for example, which has ABS and DNV approval as well as ISO 9001:2008 accreditation, consists of a modified standard weld neck flange with a patented internal groove profile. There are no moving parts, with simplicity of construction a key benefit. This starting point of having a standard flange is particularly appealing to conservative pipeline engineers who want to avoid anything too radical and like to remain in their comfort zones.

graph img

Another benefit in modifying from a standard flange, unlike many other mechanical connection solutions, is that it can be delivered to the operator within hours without production delays and without the need to access specific materials and suppliers. Some of the cost savings associated with this solution, when compared with traditional welding, are outlined in Figure 2 (above right).

flexible pipe

With Quickflange, the flange is machined in such a way that it can slide onto the pipe itself without the use of heat or other potential ignition sources and a hydraulic tool is then used to activate the flange, resulting in a mechanically robust flangeto-pipe connection and a less onerous installation compared to other more cumbersome mechanical systems. A cutaway of the flange and the installation process are shown in Figure 3 (right). The metal-to-metal seal also ensures that there are no gaskets that can be affected by temperatures and fluids. Third party qualification has also demonstrated that the process has no detrimental effects on the pipe and performance.

Typical applications to date include pipework and new spool tie-ins; the replacement of existing flanges; fitting flanges in space-restricted areas; replacing damaged or corroded piping; and the insertion of valves. Sometimes, it has just been used to avoid welding in inaccessible areas. Flexibility is also increased by its greater size coverage and its applicability to a wide variety of pipe materials, ratings and flange types. In addition, with the operation often taking place in a confined area, there is no adverse impact on production and no need for hot-work permits, pressurized welding habitats, and the resulting paperwork and costs.

Furthermore, as well as the cost savings through reduced paperwork and personnel requirements, the flexible,long-term rental model also ensures that costs are more predictable with no additional costs relating to rental equipment and increased personnel requirements if a particular job is delayed or moved. And the flexible nature of the solution as part of a complete connection system, rather than an ad hoc series of products, means that it can fit easily into any maintenance or fitting scenario.

The Quickflange solution was first supplied in 2005 to Statoil’s Gullfaks platform offshore Norway and the most recent deployments include Fairfield’s Dunlin Alpha platform in the UK North Sea, in response to corrosion issues on a flare header drain; a three-year hire agreement with Apache North Sea; and installation on BHP Billiton’s Pyrenees project, offshore Western Australia.

In January this year two Quickflanges were installed on a ZADCO (Zakum Development Company) accommodation platform in the Middle East. After hydro testing, the fabricated spools were sandblasted, painted and installed on the discharge line of the platform’s fire water jockey pump to replace the existing corroded spool. This solution is expected to significantly reduce the work scope and duration in connecting flanges to utility piping systems in a live environment on the Upper Zakum field in the future.

Heading subsea

The same flexible, piping connection solution could also be deployed on subsea piping, with additional benefits. For example, since the flange is a third of the length of many other mechanical-based products it is easier to handle and requires less diver time to install. Less time would also be needed for removing coatings, cleaning and deburying, and no specialist pipe preparation is required.

runeRune Haddeland joined Quickflange as CEO in June 2011. He has 15 years’ oil & gas industry experience, having held senior level post in Norway with Roxar Flow Measurement, TD W Offshore Services and Ymir Energy

Funding was secured last year via the Petromaks research programme, coordinated by the Research Council of Norway, to further develop the product’s subsea capabilities. This work is ongoing and includes extending operating pressures to 250 bar, researching material properties, ensuring that the flanging tools are suitable for operating in water; and increasing pipe diameters. Other collaboration partners in the programme include the University of Agder, based in Kristansand and Grimstad; DNV; the independent research organisation Sintef; Scotland’s National Hyperbaric Centre, and Brazilian operator Petrobras.

Initial subsea testing took place in partnership with Petrobras, with Quickflange deployed and activated in a specialist water tank and divers supporting the installation process. Key criteria, such as speed of installation and ease of use, were measured. To date, testing has gone well, with installation times of only 50 minutes. Further testing is to take place to confirm sealing and joint integrity.

A 4in solution is also being tested at the National Hyperbaric Centre in Aberdeen, simulating 250m water depth. The R&D programme is also looking into the development of mathematical models, optimization of connection methods, and the potential for working on subsea pipe diameters up to 30in.

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