Riser Tensioning System

Description

All Dril-Quip Tensioning Systems feature the same highly-engineered, reliable and field-proven materials and components:

• Design life of 20-25 years
• Designed with the capability of operating in all riser modes with one cylinder out
• Low volume hydro-pneumatic cylinder takes advantage of a patented feature to minimize the size of the external accumulator
• Cylinder Barrel ID sealing surfaces are plated with engineered hard chrome for long life and tested in excess of 1 million cycles to simulate 20 years of cylinder movement (based on global riser analysis)
• Seals are a redundant, dual, elastomeric arrangement for long-life, high-pressure sealing
• Pressure relief devices are connected to accumulators to prevent over-pressurization of the cylinder accumulator assembly
• Stainless steel plumbing between the cylinders and the accumulators
• Tensioner Cassette Frame design optimized using FEA to minimize weight and improve fatigue life
• Dril-Quip offers two types of riser tensioning systems: pull-up style and Ram (push-up) style
• Strokes up to 30 feet and tensioner capacities up to 4,000,000 lbs.
• Push-up designs offered with Ram Style tensioner cylinders

Pull-up Style Tensioner

The heart of the tensioner system is the pull-up cylinder/accumulator assembly. The unitized assembly is comprised of a hydro-pneumatic cylinder, an external high-pressure accumulator, a low-pressure accumulator, and upper and lower-end connections.

• Pull-up tensioners offered in straight pull-up (mounted below cassette) or tendome (mounted above cassette)
• Offers benefits of traditional, field-proven, pull-up tensioner designs and includes spherical end bearings that allow up to 10° of angular misalignment between the riser and the platform
• Solid bar tensioner piston rod has external surfaces clad with a field-proven, cobalt-based alloy that is impervious to drilling/completion fluids and salt water spray
• Hydraulic control system, fluid maintenance cart and tensioner cassette are standard offerings for these systems
• Designed for Spar applications that have a keel and use a Keel Joint for centralization of riser
• Used when large strokes and high top tensions loads are present (typical of ultradeep Spar applications)
• Includes spherical end bearings that allow angular misalignment between the riser and the platform
• Both cylinders and HP accumulator are installed and serviced from the load structure