A new lease of life in stormy times

Louise Smyth

Andrew Courtney explains why oil and gas companies should be looking to introduce new approaches to repair and refurbish their equipment 

During the past 12 months the situation we faced as a supplier to the oil & gas sector was somewhat concerning, but no one anticipated the oil price per barrel to drop to US$28 at the start of 2016. The speed and depth of the impact on the supply chain within the sector has been surprising and many companies are now faced with a ‘sink or swim’ dilemma.

Surface Technology has always endeavoured to work in partnership with oil & gas customers and investigate ways in which they can reduce costs, waste and environmental impact through effective repair and refurbishment of offshore equipment. 

Despite the wide array of surface solutions available to repair and refurbish critical components, many oil and gas companies are not utilising these to their full affect and may be missing valuable cost saving opportunities. 

Here, we outline a range of critical oilfield equipment that can be repaired and refurbished and how coatings can extend their operational life. The range of processes available include thermal spray, selective plating processes such as the Sifco Process, painting to marine specification from spot repairs to full asset re-coating, machining and grinding, NDT inspection and pressure testing.

Valve applications

Typically valve bodies and seats can suffer from corrosion and abrasive wear in use when particles are introduced between two moving surfaces. Thermal spray can refurbish them to their original condition using high velocity oxy fuel (HVOF) coatings eliminating the need to purchase new parts.

When it comes to drilling equipment, issues with the manufacturing process can also lead to a need for component salvage. For example, Surface Technology received the sealing bore of an outer connector sleeve – a critical part of the drilling system – that had been scored during the manufacturing process. A HVOF thermal coating was recommended due to its wear, corrosion and oxidation-resistant characteristics. Once coated, the surface profile of the sealing bore was re-machined to meet the manufacturer’s original specification and then comprehensive inspection and non-destructive testing (NDT) to ensure the part had no microscopic cracks or inherent weaknesses.

Meanwhile pipelines and Christmas Trees, which are used in subsea oil drilling operations, are subject to harsh undersea conditions, but this equipment can be cost-effectively refurbished by working with an oil & gas coating specialist. Surface Technology uses a bristle blasting method as it enables rapid spot repair to small and medium sized areas.

Subsea/marine risers

Larger components with threaded connections such as risers and tethers for tension leg platforms present a coating challenge to the surface finishing industry due to their size and complex handling and resultant health & safety issues. Surface Technology has a facility in Renfrew, Scotland specifically for handling larger and more complex work pieces.

A blowout preventer (BOP) is a large high-pressure valve used to prevent the uncontrolled flow of liquids and gases during drilling operations. A common industry problem is mechanical damage caused to the internal sealing diameter of the valve. The most common method of repair is to weld clad with Inconel. However, a more dynamic method of repair would be an HVOF thermal coating due to the moderate transfer of heat to the powder particles and to the work piece. 

In-situ repairs

Some repairs can also be carried out in-situ without significant disassembly using the Sifco Process and Surface Technology’s oilfield equipment preservation service. The Sifco Process is a method of electroplating localised areas on components without the use of an immersion tank. There are many benefits to choosing selective plating, including the ability to focus the plating onto specific areas of a component, enabling parts to be plated in-situ, helping to minimise downtime and production delays.

In contrast to tank plating, the Sifco Process does not require extensive masking or special fixtures to plate the component. Deposits can be plated at rates that are 30 to 60 times faster than conventional tank plating.

The benefit of having a complete approach to coating solutions is that customers can be assured that the correct solution will be specified through dedicated technical expertise. 

Andrew Courtney is operations director at Surface Technology.

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