Russian oil pipelines receive new steel
by David Fleschen
Material scientists NITU MISiS together with PAO Severstal created a new Severkor steel for field pipelines in order to reduce the environmental risks of oil production and increase its efficiency due to increased corrosion resistance. The first test pipe from the developed rolled steel passed an annual test at the Kokuisky oil and gas field Lukoil in the Perm Territory. In October 2019, the company presented an expert opinion confirming the unique resistance of the production pipes from Severkor rolled products to the aggressive environment of transported crude oil and salt solutions.
Severkor rental was developed by scientists of NUST MISiS together with one of the world's largest metallurgical companies - PAO Severstal. The need to develop a new steel grade is due to the difficult conditions of oil production in domestic fields.
Existing oilfield pipes operate 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 the emergence of unpredictable accidents, which are often accompanied by pollution of vast territories.
Scientists of NUST “MISiS” together with specialists of PJSC “Severstal” have proposed an innovative technology for the production of 2000 rolled steel at a broadband mill for the manufacture of corrosion-resistant straight-seam field pipes with improved mechanical characteristics and increased corrosion resistance. The use of the new Severkor steel grade will significantly reduce environmental risks and operating costs in oil production, including in hard-to-reach fields in Western Siberia, where pipe repair and replacement are complicated by the delivery conditions, and the aggressive composition of hydrocarbons causes an increased level of corrosion wear.
At one of these deposits, an industrial test of new steel in “combat” conditions took place. The pipe made from the developed rolled products was operated throughout the year as part of the bypass line of the Kokuyskoye field aqueduct in the Kungur city area. At the end of the test period, the experts of the corrosion protection department at the Lukoil-Perm projects conducted a study of the chemical composition and structural state of the pipe metal, through which the so-called bottom liquid was supplied — a mixture of primary crude oil with highly aggressive hydrogen sulfide-containing water.
The corrosion rate in a pipe made of new steel was only 0.008 mm per year, that is, the depth of “corrosion ulcers” from the action of a corrosive liquid on the metal was less than surface defects of the rolling mill. In the future, it is planned to issue a guarantee for at least a twofold increase in the life of pipes - from 2 to 4 years, obtained using the developed technology.
“After a year of work in the oil field, the pipe did not get noticeable wear. A technology developed by PJSC Severstal for the production of rolled metal for the manufacture of longitudinal oilfield pipes provided a real increase in their corrosion resistance, ”says Alexander Komissarov, one of the project’s developers, the head of the Hybrid Nanostructured Materials Laboratory of NITU MISIS. - This result was obtained through the use of fundamentally new alloying schemes (adding special components to the composition of materials to improve the properties of the base material) and developed modes of smelting and rolling, which provide the necessary structural-phase composition of steel in the production of rolled steel. On the whole, the obtained results emphasize the effectiveness of the orientation of the scientific developments of NUST “MISiS” towards solving applied problems of domestic industrial production in cooperation with leading metallurgical enterprises. "
Scientists of the project’s research team were able to calculate the conditions for complex microalloying of the melt with elements such as chromium, copper and nickel to obtain the necessary properties. The introduction of these metals into liquid steel made it possible to control the composition and content of corrosive non-metallic inclusions, thereby reducing their negative effect on its properties.
According to the developers, the use of rolled steel for the manufacture of oilfield pipes, obtained by the new technology of NUST MISiS, adapted to the production conditions of PAO Severstal, will significantly reduce both operating costs and environmental risks of oil production. In addition, the manufacture of pipes by welding (and not, for example, seamless) will help reduce their cost and increase the efficiency of oil production.
According to Alexander Komissarov, the technology is very competitive by world standards. According to the development results, three patents of the Russian Federation have already been received, and an application for an international patent has been sent.
Source and Photo: NUST MISIS