Custom hydraulic motor developed for high-pressure valve

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Parker Hannifin has designed and built custom hydraulic motors that are now playing a vital role in helping Cameron, a major oil and gas flow equipment supplier, make deep sea oil wells safer, more productive and more profitable.

Custom hydraulic motor developed for high-pressure valveOil wells are equipped with blowout preventers (BOPs) at the cap of the well to shut quickly around the drill pipe or to seal the open wellbore in the event of a well control problem; in essence, they contain pressure in the well to avoid a potentially catastrophic blowout that could impact on lives, capital equipment and the environment.

Cameron BOPs are installed on half the floating oil production platforms operating worldwide and on more than 70 per cent of the mobile jack-up platforms that can be moved to different locations on the seabed. In 2008, the company's engineers embarked on a programme to develop a new generation of blowout preventers capable of operating at the extraordinary depths and pressures that the industry was beginning to reach.

While existing devices operated at pressures of up to 15,000psi, Cameron wanted to make BOPs that could work and contain wellbore pressures of 20,000 psi in water depths up to 15,000ft. These extreme pressures and depths presented huge engineering challenges, both in creating a BOP that could shut quickly enough when required, and in ensuring that, once shut, the device could contain the well with no leaks.

Pressure and packaging

High-pressure capacity was not the only issue facing the Cameron engineers. Space on the BOP stack of an oil well was already at a premium; the 'Christmas tree' structure fitted at the top of the well must contain not only blowout preventers but also a range of other chokes and valves used to control flows into and out of the well. Blowout preventers therefore need to be as compact as possible. They also need to operate reliably for many years in deep sea conditions, and routine maintenance must be as straightforward as possible so it can be conducted without disrupting oilfield operations.

During early prototype testing the new Cameron BOP hydraulic locking mechanism, initially powered by a standard Parker vane-type hydraulic motor, was not optimised for the application. With time running out before the prototype was due to be qualification tested, Cameron's engineering team in Houston, Texas, explained their issue to Joe Kovach, vice president of Technology at Parker Hannifin. Realising that Parker would be able to help, Kovach sent a text message during the meeting to his technology development manager Lori Martinelli, who was based 1500 miles away in Cleveland Ohio. Two days later, a team of Parker engineers arrived at Cameron's headquarters to discuss the problem.

Once they understood Cameron's requirements, the Parker team set to work designing a motor for the new hydraulic actuator that could meet the demanding specifications. The designers used the extensive experience of extreme conditions hydraulic equipment to create a design that used a 250cc displacement motor that was designed to operate a locking mechanism able to operate and contain wellbore pressures of up to 20,000psi.

Safety and backup features

The unit, which was more compact than Cameron's existing design, also included an array of safety and backup features. It could, for example, be actuated by a remotely operated vehicle (ROV) in the event of a total hydraulic failure at the wellhead, which is claimed to be a first for this application in the oil and gas industry. Three weeks after their initial meeting, the team returned to Cameron to discuss their idea, and five days later the oil equipment firm signed an order for a prototype.

Parker manufactured the prototype unit at its Calzoni Facility in Bologna, Italy, and sent the first unit for testing at Cameron in the middle of September. Cameron put the prototype through an exhaustive validation process over the next two months, and signed off the design for production at the beginning of January 2009. By the end of March, the new actuators were arriving at Cameron's manufacturing facility for installation on the first of its new generation of BOPs.

To date, over 100 motors have been manufactured and shipped to Cameron; they are already being installed on BOP stacks for operation on wells throughout the world. Joe Kovach concludes: "Our work with Cameron is a great example of the way Parker uses speed, innovation and dedication to customer service."

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