The Oil Search / ExxonMobil Kumul Oil Platform is located in the Gulf of Papua, 40km off the southern coast of Papua New Guinea. To extend its life and increase capacity, a $25 million “Topside” rejuvenation project was undertaken.
During operation, any water or oil that drains from the platforms structure or from its production systems is channelled into the open drain caisson (the leg of the rig) to prevent any environmental impact on the sea around the rig. The hydrocarbons and excess water that collect in the caisson are then pumped to the closed drain accumulator for safe disposal via a “take-off” tanker.
The caisson is angled under the water and so to pump the fluid from the caisson to the accumulator required a 13m long vertical sump pump which had to be installed within the caisson and operate at a 5 degree angle from the vertical.
To prevent the build-up of marine growth an arrangement for low pressure injection of hypochlorite was also specified.
Amarinth was approached to deliver a cost effective solution to a very tight deadline for this difficult engineering requirement which would be operated on the other side of the world.
Although a vertical sump pump was specified for the duty, the height restriction of the platform meant that a standard VS4 pump could not be installed.
The 5 degree angle of the caisson also presented further challenges as the pump had to be carefully lined up with the caisson wall and operate reliably at this angle.
Using a combination of its proven API 610 VS4 pumps and the work it had done previously on platforms with restricted headroom, Amarinth designed a bespoke modular API 610 VS4 vertical sump pump that could be dismantled and installed in four sections and removed in sections for subsequent maintenance.
To ensure that the pump was perfectly aligned with the caisson wall, working closely with the customer Amarinth designed an innovative adjustable roller system on the pump that aligned with guide plates attached down the inner wall of the caisson as the pump was lowered in.
The bearings and seals were put under additional pressure due to the 5 degree angle. To guarantee the performance and reliability of the pump Amarinth built a test rig to replicate the operating conditions and mounting system to ensure that the final design took account of the additional stresses and vibrations as a result of the alignment.
Delivered to the deadline
Drawing on the ingenuity of its engineers, Amarinth was able to deliver a very cost effective solution to PSN that met both the requirements and the tight timescales of the project.
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