Wind turbines whose power supply exceeds 5 MW can weigh as much as 400 tonnes, are between 100 and 150 metres tall and have rotors with blades spanning 60 to 70 metres.
EUROPIPE and its industry partners have developed the Vario Base® jackets, a novel approach regarding the structural design of offshore wind turbines. In this system, cast steel joints are attached to the four legs of the structure as connecting elements for the lateral pipes. This first of all achieves an exceptionally favourable distribution of weight at the joints, where stress peaks usually form.
Secondly, the joints make it easier to connect lateral and longitudinal pipes with a circumferential weld seam. Because of the high degree of automation in welding and inspection, the process, which can be transferred directly from pipeline installation, is both cost-effective and of high quality. EUROPIPE supports this by manufacturing standardised pipes with very tight tolerances.
This is important as the entire system is extremely prone to strain through wind, waves and the movement of the rotors.
Tendon pipes – pipes for the tension legs of offshore platforms – connect the floating structure of a TLP with the sea floor. The buoyancy of the platform puts tension stresses on the pipes and exposes them to fatigue. Pipes for tension legs are therefore one of the most safety-critical components of this type of platform. The combination of heavy wall thickness, high toughness levels and extremely tight geometrical tolerances can be fulfilled worldwide by a few authority approved pipe mills only. EUROPIPE is one of these mills and carries the longest track record with the most challenging projects.
Conductor pipes are pipes for drilling-rig boreholes and oil wells, which stabilise the ground around the top of the well. The steel grades used depend on the environment of application. Conventionally, standard steel grades X56 – X65 are used, however in more demanding applications, heavier wall thicknesses or steel grade X80 are chosen.
The typical dimensions have an outside diameter of 610 – 914.4 mm (24" – 36") and a wall thickness of 15.88 – 45.0 mm (0.625" – 1.77"). In special cases up to 50.0 mm (2.0").
The transportation and storage of LNG in pipes on ships can lead to cyclic loading due to fluctuating internal pressure which exceeds the standard pipeline operation range. In this special case, the design of the pipe is based on the fatigue strength rather than on the static strength.
EUROPIPE and Salzgitter Mannesmann Forschung (SZMF) have developed the HIFA® pipe with enhanced fatigue strength to allow for a design with a higher stress range or a larger number of cycles.
In a trial production of HIFA® pipes, statistical evidence was recorded to achieve DNV approval for EUROPIPE.
A slug catcher is a piece of equipment that is used in upstream production facilities to remove the slug from the gas.
The design temperature is mostly 0°C (32°F) or lower. Depending on the gas condition the pipes have to be heavy in the wall thickness or made out of sour gas resistant material or the combination out of both requirements.
A Drilling Riser is basically the extension of the borehole to the drill rig. A tension system on the vessel continually pulls the top of the riser so that the riser system is always under tension. This situation provides a very stable and always perfect vertical connection to the borehole for the drilling operation.
The Drilling Riser is exposed to extreme loads, not only from the inside pressure from the drilling operation and in the final stage from the pressure of the reservoir, but also from tension and high fatigue loads due to the motion of the vessel. This challenging application leads to an extremely demanding specification for the pipes.
The main features are
• Tensile strength in both longitudinal and transverse direction
• Excellent toughness at low temperatures
• Limited hardness
• Tight tolerances for - the out of straightness - the out of roundness - the inside diameter
The typical dimensions are an outside diameter of 533.0 mm (21") and wall thicknesses of 22.2 mm – 31.8 mm (0.874" – 1.25"). EUROPIPE can deliver pipes of steel grades up to X90 API 5L material (X100 is under development).
Only the best-in-class pipes are able to fulfill this specification with sufficient margin to ensure a perfect performance.