Around the world, the extraction of oil and gas on the high seas requires innovative and sophisticated piping solutions using high-quality materials.It is no longer uncommon for oil companies to drill for oil more than 10,000 meters below the surface.
To ensure long-term profitability, any resource needs to be minable for at least 25 years.Schoeller Werk in Germany contributes to the necessary quality and planning assurance with its heavy duty control lines and chemical injection pipes for the offshore industry.Their technical design allows them to withstand not only the extreme pressure conditions prevalent in the deep sea, but also extremely high temperatures and corrosive liquid media.
Globally, more than 2,000 offshore rigs and many more independent wells are continuously producing oil and gas.The technical equipment of these plants places extremely high demands on carefully selected suppliers of the stainless steel industry.Schoeller Werk took up the challenge at sea 35 years ago and has been a leader in the industry for many years.At its base in Eifel, the company not only produces pipes for various industries, but also provides technically superior solutions for drilling rigs.
For one company, TCO Norway alone, Schoeller Werk, a service provider to Norway’s state-owned oil company, has supplied more than 500,000 meters of pipeline since winning a customer order in the spring of 2014.The heart of this partnership is numbered by high-quality nickel-based alloys.825 and 625.There are also austenitic tubes made of grade 316 Ti stainless steel.The pipelines delivered have impressed Statoil so much that it has defined them as the standard for its own specification.In addition to a wide range of materials, a wide range of diameters and wall thicknesses need to be manufactured – Schoeller tubes of the Sierra type cover all possibilities.The piping design and the corresponding quality tests enable the final solution to withstand internal pressures up to 2,500 bar without difficulty.In addition, the high-quality material, together with the improved surface quality derived from the wire drawing process, is resistant to the effects of salt water and other aggressive media.
One of the features of the plug-in tube is its geometrically precise curvature and high welding quality.In principle, the base material is not a factor, and single pipes of up to 2,000 meters can be manufactured.Internal mandrels (plugs) are used to smooth the inside of longitudinal welds.Combined with an external mandrel, the initial cross-section of the tube can be reduced by up to 50%.All in all, this is a longitudinally welded solution that gives the impression of a seamless tube.Observing the microstructure of the material revealed that the weld was barely detectable even after the pipe was drawn.Attributes such as these are key plus points for Schoeller Werk’s offshore clients.
The offshore industry uses these pipes as hydraulic control lines for safety valves and for pumping chemicals into oil reservoirs.In this way, they support the entire extraction process.Injection tubes allow rig operators to target chemicals to liquefy petroleum, thereby improving its flow characteristics.In a complex manufacturing process, pipes are subjected to various tests before installation to ensure the exceptional quality of the product.Metal strips are welded together with longitudinal seams using a tungsten inert gas (TIG) welding process and then rolled into tubes.In addition to the mandatory eddy current test, the tube is then subjected to an underwater air (AUW or “bubble”) test.The tube is submerged in water and filled with air up to 210 bar.Perform a visual inspection along the entire length of the tubes to check that they are sealed.In order for Schoeller Werk to be able to provide its customers with the required lengths of 15,000m and above, the individual pipes are rail welded together and X-rayed to check that the rail welds are airtight and free of any air holes.
Schoeller Werk also performs hydraulic tests on the control and injection pipes before delivery to the customer.This involves filling the finished coil with hydraulic oil and subjecting it to pressures of up to 2,500 bar to simulate the extreme conditions sometimes encountered in offshore operations.
In addition to pure pipe manufacturing, Schoeller Werk also offers customers in the offshore industry a comprehensive service package, for example the encapsulation of pipes with plastic sheathing in so-called flat packs.This means that the tube bundle can be connected to the extraction tube and protected against bending and pinching.Other services include flushing and filling pipes.Here, the inside of the pipe is flushed with hydraulic fluid until the fluid reaches a specified ISO or SAE purity level.Fluid filtered in this way can remain in the pipe if the customer wants it, meaning the user has a product that can be used.In addition, the tube bundles can be equipped with wires or stainless steel support cables.In addition, due to the smooth inner surface, the plug-in tube is also very suitable for use as a conduit for the transmission of optical cables.
Schoeller Werk joins the international market in its cooperation with the offshore industry.In addition to Norway and the United Kingdom near the European North Sea, Russia, Saudi Arabia, the United Arab Emirates, Africa, Asia, Australia and South America are among the main target areas for the use of Schoeller control lines and chemical injection pipes.