Deniz dibinde paslanmaz çelik uygulaması
Rodrigo Signorelli, Otokumpu Marine and Energy Technology Manager, will introduce the application of stainless steel and alloys with high safety and reliability in the seabed. These include Sanicro®35, which can be used in harsher environments and is less expensive than Alloy 625.
pipeline
Oil and gas are transported through control lines and chemical injection lines under the sea. The control pipeline hydraulically controls the underground safety valve, which automatically shuts down production when the pressure is insufficient to ensure safety. Through the pipeline, chemicals can be injected into the well to accelerate the separation of sand from oil and gas, reduce foam, increase flow rates, and inhibit corrosion. In the submarine environment 10,000 meters below the surface, the reliability of the material is very important, the selection of corrosion-resistant alloy coiled tubing to manufacture the pipeline, not only has strong corrosion resistance, good mechanical properties, but also can ensure that the material under repeated pressure and pressure relief to maintain excellent fatigue performance. Alloy 825 has excellent corrosion resistance and is ideal for control lines and chemical injection lines. In addition, Supra 316L can also be used to make pipelines in relatively good corrosive environments.
Umbilical cable
The umbilical cable brings together many subsea services, connecting subsea Wells to surface oil and gas platforms, providing monitoring, power and communication services for subsea exploration activities and carbon dioxide storage, covering a variety of applications such as pipelines, power and data cables. In the seabed transportation of oil and gas, need to lay a very long umbilical cable, you need to choose high pressure resistant materials, seamless pipe because there is no seam, is the ideal choice for umbilical cable, but seamless pipe production cost is high, the length of a single pipe is limited, need multiple pipes for welding use, weld seams may exist gaps, need special attention in the test. This also increases the cost and complexity of umbilical cables. In recent years, more and more design engineers use continuous welded pipe instead of seamless pipe. The length of a single tube is longer, reducing the number of manual welding, and continuous machine welding ensures the consistency of the process, making it more accurate and more uniform wall thickness. Compared with seamless pipes, continuous welded pipes can make thinner wall thickness, thus reducing the use of materials and reducing costs. The Forta SDX 2507 is ideal for umbilical cables due to its high corrosion resistance and mechanical strength.
Flexible pipe
Flexible pipelines are often used as risers to transport oil and gas from the sea floor to the surface, as well as subsea oil pipelines. These pipelines are suspended in seawater during use, and it is important to maintain a stable state in the dynamic environment of seawater. In its construction, flexible pipes have a number of layers, including leak-proof thermoplastic barriers, tension – and pressure-resistant armor layers, and collapse-resistant stainless steel housing. Supra 316L is usually used for shallow water projects, and Ultra 254 SMO and Ultra 6XN are used for projects with high salt content. In deep-sea projects, where higher water pressure requires higher strength materials, duplex steel becomes the best choice, such as Forta LDX 2101, Forta DX 2205 and Forta SDX 2507.
Composite pipe and lined pipe
Undersea pipelines are key to moving oil and gas from production sites to refineries. Corrosion resistant alloy is the best choice, but the alloy cost is high, if all the use of alloy to make pipes, the price will be very expensive, another is the use of mechanical lining pipe or composite pipe, the inner diameter is made of corrosion resistant alloy, the shell is the use of carbon steel, this pipe will be relatively cheap. The composite pipe enables metallurgical bonding between the corrosion-resistant alloy and the outer pipe, with no gaps between the two layers of material, reducing risk in high-pressure and high-temperature applications. The professional rolling mill that produces the composite plate sandwiched the corrosion-resistant alloy and carbon steel in the middle, and made the composite plate after many processing. For the processing of wider thick plates and small batch composite plates, the explosive composite method is used to produce. Another way to make composite plates is surfacing welding, where corrosion-resistant alloy wires or welding strips are welded to the inner surface of carbon steel pipes or fittings. Mechanical lining tubes are made of carbon steel tubes lined with corrosion resistant alloys. The most common process involves inserting a corrosion-resistant alloy liner into a carbon steel casing and pushing the liner tightly into the tube body using hydraulic expansion or mechanical spinning. Some manufacturers also strengthen the bond between the two layers by heating the outer tube or adhesive. These technologies do not require as much energy and production infrastructure as metallurgical compounding. The cost is relatively low, but the metallurgical composite is stronger than the mechanical composite. Composite and lined pipes are generally made of austenitic Supra 316L and its high molybdenum variant Supra 316L HiMo, with higher grades Ultra 317L and Ultra 904L selected for more corrosive environments. Some will choose Ultra 254 SMO because it is a super austenitic stainless steel containing 6% molybdenum and added nitrogen, which can be used in harsh environments requiring high resistance to uniform and local corrosion. For sulfur-containing gases, Outokumpu also offers Ultra Alloy 825, a titanium-stabilized austenitic nickel-based alloy widely used in pipeline systems in the oil and gas industry.
Sanicro®35
Alloy 625, which is highly resistant to corrosion due to its 58% nickel and 10% molybdenum content, is used in demanding subsea environments, but is expensive and volatile, creating project planning and delivery challenges. Sanicro®35, produced by Otokumpu, is a cost-competitive Alloy with excellent corrosion resistance that can replace nickel-based Alloy 625 in some harsh use environments and ensure service life. With 35% nickel and 6.4% molybdenum, Sanicro®35 not only reduces costs, but also reduces the impact of price fluctuations, making it an ideal alternative to Alloy 625. Sanicro®35 fills the market gap between high performance stainless steel and nickel-based alloys. It can be used in a variety of harsh corrosive environments, including seawater, acid and alkali, erosion corrosion, pitting and crevice corrosion, and stress corrosion cracking. In addition, it has high mechanical strength, good formability, weldability and processability.
Sustainable development
Sustainability is increasingly important, and oil and gas operators also need to measure and report on sustainability, so in addition to ensuring the performance of materials in subsea applications, reducing the carbon footprint is becoming increasingly important. That’s why we take the initiative to provide our customers with accurate carbon footprint data. In November 2022, we started publishing the carbon footprint of specific products on product certificates, which combines a rolling average of all data affecting the carbon footprint and is verified by engineering consulting firm WSP. Our customers have access to accurate carbon footprint data, enabling them to calculate their carbon footprint more accurately. Until now, Oems have typically used the average carbon footprint to calculate, for example, the average carbon footprint per kilogram of stainless steel in European mills is 2.8 kilograms. But in fact, the carbon emissions of Otokumpu per kilogram of stainless steel are only 1.8 kilograms, or even less. The practical benefit is that they have an accurate number so that they can accurately calculate the carbon footprint of the product.