High-performance hammers capable of driving piles in ultradeep water are being developed by MENCK to support the oil and gas industries' efforts to develop hydrocarbon reserves in these water depths.
With the hydrocarbon reserves in shallower water already reasonably well accessed, operators have been turning to ever-deeper waters, where the safe and cost-effective development of subsea prospects presents huge execution challenges. Factors such as immense depths to the seabed, high pressures, strong currents, remote locations and complex geology mean that highly reliable engineering solutions are essential.
Fabian Hippe, sales manager, MENCK, says, “We routinely offer highly advanced and reliable underwater pile-driving hammers that can be used to depths of 2000 m. They have helped to install deepwater anchor points on projects around the world and are the only genuinely underwater hammers available.”
“There is no other system that can drive piles in deep water, and now we are extending the capability of our equipment to water depths in excess of 3000 m,” says Hippe. “This will create a host of new opportunities for the industry.”
Experience shows that deepwater driven piles typically provide the most reliable and easy-to-use mooring points. They facilitate positioning better than drag anchors and are less sensitive to varying soil conditions than suction piles or plate anchors. In addition, they provide solid foundations for any kind of subsea architecture, including mono-piles for subsea manifolds and foundation piles for subsea templates. They can be used as riser foundations, pipeline termination piles or anchor points, and can even be used to pre-install well conductors.
Sophisticated solution
MENCK’s range of hydraulic underwater (MHU) hammers draws on over 130 years of experience in designing and manufacturing pile-driving and hydraulic-based systems. Three series of hammers are available: the MHU-S range for above- and underwater (to water depths of 400 m) pile driving; the MHU-T for water depths to 2000 m; and the soonto-be-available MHU-U for water depths exceeding 3000 m. They can all be combined with the company’s dedicated submersible hydraulic power packs, which can be configured to drive various pile sizes.
In deep water, a girdle-type electrohydraulic power pack is fitted to the hammer. This minimises the hydraulic hose length to provide the highest health, safety and environmental standards possible. But the biggest advantage of generating hydraulic power at depth is that it reduces energy losses. If the hydraulic power were to be produced at surface, substantial power would be consumed in overcoming the losses within the umbilical and the hydrostatic pressure.
An umbilical carries the electrical power required by the hydraulic pumps, the communication lines that provide realtime control and feedback, and the compressed air for creating a gas-saturated environment inside the hammer. Electric motors drive a hydraulic piston that has a housing filled with compressed air to increase acceleration and reduce friction. As a result, the hammer’s efficiency (net driving energy over hydraulic energy) is over 95%.
A sophisticated control system enables the operator to interact with the electronic sensors on all the key components. This provides real-time feedback during pile installation and generates valuable installation and driving records for postjob analysis.
Breaking new ground
MENCK’s deepwater pile-driving systems have been used in 28 deepwater anchoring projects during the last 10 years. As Hippe explains, several milestones have been created along the way: “Our underwater hammer technology was used in the Gulf of Mexico to install the largest tension-leg platform (TLP) ever built,” he says. “It also played a role in the first TLPs in West Africa and Asia–Pacific.”
Hippe continues, “The system was originally developed in the late 1980s for water depths of up to 1000 m, but we have continued to push its use deeper. We were involved when the world depth record for deepwater driven piles was set at 1220 m, at 1400 m and then at 1565 m. We have held the record for the last 15 years.”
Operational experience is an invaluable element of the product development cycle. “We do not just design and manufacture the equipment,” Hippe says. “We also operate our own rental fleet, which gives us vital operational experience that we feed back into the development and design process. This has led to an extensive range of safety features, an expedited commissioning process, easy-to-maintain modular concepts and the highest level of reliability.”
MENCK clients undertaking the more challenging projects have recognised the value of commissioning the company to take care of every aspect of the piling process. MENCK’s engineers can become an integral part of the customer’s team by providing optimum pile designs, selecting the most appropriate equipment and managing the pile installation programme to ensure that it aligns with the overall project.
Developments in deep and ultra-deep water require outstanding engineering expertise and innovation, plus robust and reliable equipment. MENCK has drawn on its specialist technical know-how in this field to help the oil and gas sector meet these extreme challenges head on, and overcome them.