FPSO vessels are critical in the oil & gas industry for the production and processing of hydrocarbons as well as the storage of oil. When such vessels have production capacities of over 90’000 barrels of oil per day, there is little room for ill-performing equipment on board. Where subpar performing pumps and motors are identified, service experts need to be called in for peace of mind.

Trouble down under

Unfortunately, after over a decade in operation, three API BB3 water injection pumps were subject to a number of seal failures, which were outside the routine maintenance schedules. The failures were caused by an increase in the seal chamber pressure; an issue that resulted in the owners contacting Sulzer for expert analysis and support.

Field service teams provided on-site inspection and a review that revealed a reduction in pump head and performance as well as wear caused by sand particle impingement. The high amount of sand pass-over, coupled with incomplete regular cleaning of auxiliary equipment, lead to the pumps operating at a reduced efficiency, having a detrimental impact upon production output.

Parts of a pump being checked by service engineer
The correct coating for each part can help extending the lifetime

Modifications in just 25 days

Having gained the necessary information to understand the root causes of the problem, the engineering team based in the Suzhou factory began designing the solution. Specialist engineers proposed a multi-faceted solution to combat the wear and seal issues. This included modifying internal geometries, ensuring a smoother flow and allowing particles to follow the fluid streamline more closely, resulting in reduced turbulence and thus reducing erosion.

A tungsten carbide-based coating SUME®, specially developed for sand abrasion within pumps on water injection duties, was used for coating of the impellers and wear parts due to its high wear resistance and anti-galling properties. Finally, the wear rings were upgraded in material to a ceramic type providing further wear and abrasion resistance.

The proposed solutions were approved by the customer and executed according to the customer’s outage plans. One of the pumps was upgraded, while the FPSO vessel was in dry dock, at Sulzer’s Singapore Service Center and the subsequent pumps were upgraded within Sulzer’s Perth Service Center once the vessel was back in operation in Australia.

This allowed the customer the flexibility of completing the job within their project schedules. Furthermore, having the service sites nearby gave the customer piece of mind, with the equipment being repaired to the highest level of quality and offering excellent support during the project.

Partially assembled pump
Partially assembled pump after improving the components

Out with the old, in with the new

In addition to the support with the mechanical rotating equipment, Sulzer was also able to deliver maintenance and repair work for the electrical equipment. This time, the FPSO vessel required support on the removal of an old 2 MW, 11 kV Siemens motor while simultaneously installing and commissioning a brand-new identical piece of machinery.

The original motor was removed from the vessel and sent to the Perth Airport Service Center for a full inspection, repair and testing. Specialists assessed the condition of the unit and replaced a number of components including stator leads, rotating seals and grease lines as well as remanufacturing a new terminal box to better suit the application on site.

The windings were cleaned, dried and the motor was tested at rated voltage 6.6 kV. The entire overhaul process was completed over a five-month period with the motor remaining at the service center for preservation until it is required again.

Certification is key

A trusted partnership with the serviced provider not only establishes confidence for the continued performance of electrical rotating equipment, but the safety and legality of the machinery too. Given the motors’ application in what is deemed a hazardous area in an offshore oil & gas installation, any repairs and works completed must be in line with IEC Ex guidelines and certification. Having been involved in developing the industry standards, Sulzer is expertly positioned to provide support on such equipment, reducing downtime while maximizing performance.

Our investment in Western Australia is intended to give key global oil & gas companies reassurance that a pump manufacturer will support them with local repair facilities. It is through this proximity to our customers that we can fully understand the environment in which they operate. It also allows us to build relationships, gain a better understanding of real-life operational issues and become a valuable partner to our customers.

Warren Coppard - Head of Sulzer for services in Western Australia
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