Leaks can be extremely costly, whether in terms of lost product, reduced performance, downtime and repair costs, environmental issues and fines, or a combination of these. As Furmanite Australia general manager Colin Bickerstaff says, “The financial impact of a leak is likely to be far greater than the cost of the contingency measure, particularly if the leak means pipeline shutdown, when the cost can quickly run into millions.”

Avoid delays

Leak sealing clamps provide an ideal means of repair without requiring shutdown. However, if they are not held ready as a contingency measure there is a lead time to consider which is often not taken into account. At a time of expansion and new activity in the oil and gas sector for example, this is a matter that needs ongoing consideration.

“These are not an off-the-shelf item, and stringent regulations and standards mean they can rarely be produced for fast delivery,” Mr Bickerstaff says. “If exotic materials are involved, or particularly large diameters or high pressures, the lead time is extended further. Operators may assume that the clamp can be prepared in the same time it will take to prepare the pipe and get a dive vessel for subsea lines, but the clamp will often take much longer.”

Far more cost efficient, therefore, is to plan for a leak and ensure that contingency leak-sealing measures are available for immediate application, minimising exposure and risk should integrity be compromised.

Self-sealing clamps such as FurmaSeal meet this need. Consisting of a split sleeve fitting, they attach to the pipeline to repair or provide reinforcement without interrupting normal operations. The clamps are available in 2 to 48 inch nominal bore and pressure ratings to over 3,625 psi (over 250 bar), with higher pressure ratings and special configurations for tees, elbows, flanges etc available on request. No sealing compound is needed and no welding required, as the clamps use flouro-elastomer seals which are compressed and loaded by bolting around each end of the clamp and between the two clamp halves, producing a highly effective, mechanically-actuated high integrity seal.

A traditional barrier to holding such clamps in readiness has been the need to have clamps in relevant sizes for each different line. However, the latest technology available from Furmanite now means that contingency leak sealing clamps become a truly viable measure, since clamps no longer need to be asset specific.

“Variations in nominal outside diameters and out-of-roundness can be accommodated thanks to the so-called ‘cross-asset’ clamps now available, which can be held as a contingency for a number of different lines,” Mr Bickerstaff says. “A system of interchangeable inserts and seals enables the clamp to accommodate outside diameter variations of more than 30 mm, while still meeting the vital requirement that the clamp fit properly to avoid extrusion which would compromise the seal.”

Growing recognition

Furmanite has reported that the benefits of leak sealing clamps as a risk reduction measure are increasingly being recognised and acted upon. One leading Australian oil and gas operator recently ordered four 20 inch Class 600 FurmaSeal self-sealing clamps for their subsea oil pipelines, and Furmanite Australia holds some 50 clamps of various sizes and classes at their West Australian facilities for companies in the oil, gas and refining industries in case of emergencies.

Elsewhere, Furmanite was awarded a substantial contract last year by the BP-operated Azerbaijan International Operating Company (AIOC) to supply pipeline contingency repair equipment for AIOC subsea lines in the Azerbaijan sector of the Caspian Sea. Under the contract Furmanite provides contingency measures for the 185 km 30 inch oil pipeline and 28 inch gas pipeline between Central Azeri and Sangachal Terminal, and the 18 inch in-field gas pipeline between the Central Azeri and Chirag platforms, for use should repairs or modifications to the lines be needed. These include the company’s specialist cross-asset clamp design to accommodate varying diameters and out-of-roundness that could otherwise prove problematic, given the varying pipe schedules that exist in the field.

In a slightly different approach, another operator took contingency leak sealing measures by using Furmanite design bespoke subsea sealing clamps to reinforce a 26 inch crude oil line where internal corrosion had caused wall-thinning. The three tonne clamps, each measuring 1.2 metres in length, designed to a 275 psi rating and built for a 25 year design life, were a preventative measure, strengthening the line and removing any risks associated with the wall-thinning with no disruption to production.

As a means of fast, economical on-line pipeline repairs to restore integrity, minimising damage and avoiding shutdown, there seems little question that repair clamps represent a valuable measure. Should a leak arise, the cost is recouped several-fold. Yet there still appear to be obstacles to widespread procurement for contingencies, which means risks are being taken.

Summing up, Mr Bickerstaff says “It’s true we’re seeing pipeline operators increasingly recognise the value and need to hold contingency self-sealing repair clamps on standby for critical lines. But equally it’s not uncommon for the value to be acknowledged but the measures delayed, or not put in place, because the need is not seen as a priority, the lead time required is underestimated, or there is uncertainty and internal debate as to whether the investment in the contingency clamps falls in to the capex or the opex budget.

“This is an issue that needs to be resolved, given the massive savings that these clamps could represent and the widespread negative impact on image as well as cost and operational efficiency of a leak. The availability of cross-asset clamps, so that one clamp has the potential to be applied to a number of assets depending on where the need arises, makes this contingency measure even more cost-efficient, and of particularly high value.”