Material Scientists from NUST MISIS Create a New Corrosion-resistant Steel for Oil Pipelines

MOSCOW, Nov. 26, 2019 /PRNewswire/ -- The new Russian steel called Severkor for oil pipelines has been created by materials scientists at NUST MISIS in order to reduce the environmental risks of oil production and increase its efficiency due to increased corrosion resistance. A year ago, the first test pipe from the developed steel was installed at the Kokuysky oil and gas field in the Perm Krai territory in Russia. In the fall of 2019, Lukoil company has presented an expert opinion confirming Severkor's unique resistance to the aggressive environment of crude oil and salt solutions.

Severkor has been developed by the NUST MISIS scientists by the order of one of the world's largest metallurgical companies - PAO Severstal.  The need to develop a new grade of steel was due to the peculiarities of oil development technology in most world deposits.

Existing oilfield pipes are used under conditions of constant contact with a corrosive aqueous emulsion mixture of oil and concentrated saline solutions. This leads to short periods of their operation (about 2 years) and unpredictable accidents, which are often accompanied by pollution of vast territories.

Scientists from NUST MISIS have proposed an innovative technology for the rolled steel for the corrosion-resistant field pipes production with improved mechanical characteristics. The new Severkor steel grade will significantly reduce environmental risks and operating costs in oil production, especially in the regions where pipe repair and replacement are complicated by the delivery conditions, and the composition of hydrocarbon materials causes an increased level of corrosion wear.

At one of such deposits, the annual test of the new steel in "combat" conditions took place. The pipe worked throughout the year at the oil well of the Kokuysky field in the area of the city of Kungur. At the end of the test period, the experts of the corrosion protection department for the Lukoil-Perm projects conducted a study of the chemical composition and structural state of the pipe metal, through which the mixture of crude oil with highly aggressive hydrogen sulfide water was streaming.

The corrosion rate in the pipe made of new steel was only 0.008 mm per year, that is, the depth of the deterioration from the corrosive liquid effect on the metal was less than the defects in the rolling mill.

"After a year of work in the oil field, the pipe remained virtually new. The new technology for the production of the rolled metal for the manufacture of longitudinal oilfield pipes ensured their real increased corrosion resistance," says Alexander Komissarov, one of the developers of the project, research fellow at NUST MISIS. "This result was obtained thanks to fundamentally new alloying schemes (adding dopants to the composition of materials to improve the properties of the base material), which provide the necessary structural and phase composition of steel in the production of rolled and flat products."

Scientists from the project's research team were able to calculate the conditions for complex microalloying of the melt with such elements as chromium, copper and nickel in order to obtain the necessary properties. The addition of these metals into liquid steel made it possible to regulate the composition of corrosive non-metallic inclusions in steel, thereby reducing their negative effect on its properties.

According to the developers, steel products obtained using the new NUST MISIS technology will significantly reduce both operating costs and environmental risks of oil production. In addition, the manufacture of pipes by welding (and not, for example, by the seamless method) will help to reduce their cost and increase the efficiency of oil production.

According to Alexander Komissarov, the technology is very competitive by world standards. Developers expect to receive an international patent, and in the future, they plan to issue a guarantee for at least a twofold increase in the service life of pipes obtained using the developed technology.

SOURCE National University of Science and Technology MISiS