Ultra deepwater offshore projects, defined as those of 1,500 meters and deeper, create very specific engineering challenges as extreme depths result in high hydrostatic pressure which can lead to collapse issues or buckling during installation phases. In addition, longer risers with increased load will experience fatigue during their lifetime. Lastly, ultra-deep field development, with its complex layouts and installations, calls for more accessories, such as buoyancy modules, which generate higher project costs. To rise to the challenges of demanding line pipe projects, Global seamless pipes leader Vallourec has developed a comprehensive pipe grade portfolio, which includes the X80 steel grade.By meeting the material challenges for operational welding, Vallourec’s X80 steel grade offers both sour service and fatigue sour service resistance. The benefits of risers made of X80 grade include:1. Reduced wall thickness compared to standard X65 line pipe grades for similar design pressures2. Less weight, reducing the need for buoyancy modules3. Less steel manufactured per project, meaning reduced CO2 emissions4. Greater flexibility for pipe laying by the installation vesselVallourec’s first seamless X80 grade has now been delivered for pipes with heavy wall thickness up to 40mm and for mild sour applications NACE region 2. For such applications, X80 guarantees a maximum hardness below 280 HV10 on the pipe, and an average toughness of 300J at minus 30 degree Celsius. Vallourec has been developing the X80 solution over the last 10 years, working with various engineering, procurement, and construction partners who attest to its impressive performance in mild sour environments. Vallourec, together with Subsea 7 and ExxonMobil, have performed small-scale sour service fatigue tests of pipes and welds. These results have highlighted comparable corrosion fatigue performance for X80 welds and standard welds on X65.Continuously innovating to push the boundaries of material grades, Vallourec is now working on the next X80 steel grade concept to address full sour service applications in NACE region 3. This solution is targeting wall thicknesses below 30 mm. Thanks to specific composition and manufacturing processes, lower hardness will be achieved for the pipe and subsequent welds. The first four point bend tests performed on this new concept, all following NACE TM0316 standards, are already showing good performance.In a project where riser made of 41mm thick pipes in X65 steel required the use of buoyancy modules in what is known as a Steel Lazy Wave Riser configuration. In this specific case, using X80 reduced wall thickness of the riser pipe to 32mm, which in turn eliminated the need for buoyancy modules. By enabling a steel Catenary Riser Configuration, X80 can lower project installation costs. Indeed, reducing wall thickness eliminated more than 2,000 tonnes of steel production, which translated to cost savings of around USD 2,800 per tonne. It also shortened installation time by a full 12 days and saved up to 3,500 tonnes of CO2 emissions.
Ultra deepwater offshore projects, defined as those of 1,500 meters and deeper, create very specific engineering challenges as extreme depths result in high hydrostatic pressure which can lead to collapse issues or buckling during installation phases. In addition, longer risers with increased load will experience fatigue during their lifetime. Lastly, ultra-deep field development, with its complex layouts and installations, calls for more accessories, such as buoyancy modules, which generate higher project costs. To rise to the challenges of demanding line pipe projects, Global seamless pipes leader Vallourec has developed a comprehensive pipe grade portfolio, which includes the X80 steel grade.By meeting the material challenges for operational welding, Vallourec’s X80 steel grade offers both sour service and fatigue sour service resistance. The benefits of risers made of X80 grade include:1. Reduced wall thickness compared to standard X65 line pipe grades for similar design pressures2. Less weight, reducing the need for buoyancy modules3. Less steel manufactured per project, meaning reduced CO2 emissions4. Greater flexibility for pipe laying by the installation vesselVallourec’s first seamless X80 grade has now been delivered for pipes with heavy wall thickness up to 40mm and for mild sour applications NACE region 2. For such applications, X80 guarantees a maximum hardness below 280 HV10 on the pipe, and an average toughness of 300J at minus 30 degree Celsius. Vallourec has been developing the X80 solution over the last 10 years, working with various engineering, procurement, and construction partners who attest to its impressive performance in mild sour environments. Vallourec, together with Subsea 7 and ExxonMobil, have performed small-scale sour service fatigue tests of pipes and welds. These results have highlighted comparable corrosion fatigue performance for X80 welds and standard welds on X65.Continuously innovating to push the boundaries of material grades, Vallourec is now working on the next X80 steel grade concept to address full sour service applications in NACE region 3. This solution is targeting wall thicknesses below 30 mm. Thanks to specific composition and manufacturing processes, lower hardness will be achieved for the pipe and subsequent welds. The first four point bend tests performed on this new concept, all following NACE TM0316 standards, are already showing good performance.In a project where riser made of 41mm thick pipes in X65 steel required the use of buoyancy modules in what is known as a Steel Lazy Wave Riser configuration. In this specific case, using X80 reduced wall thickness of the riser pipe to 32mm, which in turn eliminated the need for buoyancy modules. By enabling a steel Catenary Riser Configuration, X80 can lower project installation costs. Indeed, reducing wall thickness eliminated more than 2,000 tonnes of steel production, which translated to cost savings of around USD 2,800 per tonne. It also shortened installation time by a full 12 days and saved up to 3,500 tonnes of CO2 emissions.
