For decades Apex Hydraulics has been at the forefront of creative solutions for the offshore industry, providing DNV approved hydraulic cylinders for a variety of different fabrications, both above and below water. Apex recently took on a new commission from a familiar client, to build a series of tension cylinders for a tension deck.
The Client
The client is an offshore specialist company, priding itself on innovative solutions to improve operation, efficiency and decarbonisation in whatever products or systems their customers need. They work from concept through to design and manufacture.
Apex hydraulics have partnered with them a number of times in recent years, manufacturing hydraulic cylinders for their market leading tools and products for offshore energy companies.
The Project
The client commissioned Apex Hydraulics to manufacture eight 100 tonne tension cylinders for an offshore oil rig.
Whenever an offshore oil rig drills the seabed for oil, they first need to put down risers. Depending on the sea depth, this is likely to require multiple risers, connected to one another to reach the full distance to the seabed. These risers are lowered into the sea in turn, each one joined to the next before being lowered further. At the base, the riser is fixed to the seabed, and then the sea water can be pumped out of the riser, creating a dry column that engineers can work in. Tools and equipment will be extended down the riser and into the oil well.
One of the technical issues is that of the movement created by the waves. A riser moving from side to side could break, be dangerous and impractical to work with, and damage tools.
To overcome this, engineers use a tension ring, or deck, at the top of each riser, pulling it upwards, creating tension and stopping it from moving around in the waves. Each hydraulic cylinder has a calculated pull force, so that it supports the entire weight of the riser, but without pulling it off the seabed.
With a functioning tension deck, there is no room for the risers to move, because they are tethered at the bottom and at the top. This adjusts regularly according to the waves; regulated by a power pack which readjusts as required, keeping the column constantly tensioned, allowing the rig engineers to work with the drilling and cutting tools as needed.
The Cylinders
Apex Hydraulics manufactured eight cylinders, providing 100 tonnes of tension each. The client stipulated the parameters of their lifting shackles and Apex designed and manufactured the cylinders to the latest DNV rules.
They were fitted with pressure sensors and ATEX approved internal linear transducers, giving a 4-20mA output, which is used by the rig to monitor the cylinders’ positions.
The cylinders were complete with lifting eyes for ease of handling and were shot blasted and painted with offshore paint to the customer’s requirements. All cylinders manufactured by Apex are tested thoroughly in house prior to being dispatched.
The cylinders are now fitted to the tension decks and working at an offshore facility in the middle east.
Apex have produced various similar cylinders for this client over several years. The client keeps returning for more products, satisfied with the quality, workmanship, and longevity of Apex Hydraulics’ market leading design and manufacture.
Related Products
The following products were utilised as part of this project. For more detailed information on these products, click on an image below…
