V. 3 (40) / 2019 «Improving reliability of gas mains subject to stress corrosion cracking»
candidate of engineering I.V. Ryakhovskikh
doctor of chemistry, assistant professor Ya.G. Avdeyev
doctor of engineering S.Ya. Betsofen
doctor of chemistry, professor Yu.I. Kuznetsov
doctor of engineering A.S. Kuzbozhev
doctor of engineering Ye.M. Morozov
doctor of engineering R.O. Samsonov
doctor of engineering, professor V.G. Titov
doctor of engineering N.Kh. Khaplyyev
doctor of engineering, professor V.V. Kharionovskiy
doctor of engineering M.V. Chuchkalov
doctor of chemistry A.I. Shcherbakov
Evolution of the global pipeline transport is integral with genesis of petroleum industry. The first 6 km long oil pipeline was built in the USA in 1665. In the middle of the 20th century, the total length of pipelines in the world has reached 350K km; and by the early 2000s, the aggregate extension of pipelines in Russia, USA and Canada being the biggest oil and gas producers has come out to nearly 1,000,000 km. Metallurgical technologies of 1970s have boosted development of the pipeline transport, as they’ve provided fabrication of large-diameter pipes from the reinforced steels. The major Soviet, European, and Asian pipe producers have manufactured pipes 1020–1420 mm in diameter, which should have been applied for construction of the oil and gas mains working under the pressure of 5.5–7.5 MPa. At that years, the United States have suggested an innovative technology aimed at route sealing of pipelines using a Polyken film coating, which has been widely applied later in contemporary Russia for construction the largest in World gas transportation system. Nowadays, one have to acknowledge general deterioration of domestic and foreign pipelines built in 1960–1990. First of all, it depends on access of a corrosive medium to a pipe surface in the spots of film coating delamination. Most of the occurred defects could be classified as stress corrosion cracks. Density of such defects reaches few thousands per a kilometer of a pipeline.
First, a phenomenon of longtime corrosion-mechanical destruction of steel pipes called stress corrosion cracking was recorded in 1965 in the United States. Due to a pipeline emergency in Louisiana, 17 peoples have perished and 7 buildings have been destroyed in a 450 ft radius. Since this accident, the stress corrosion cracking has been assigned to the most dangerous and unpredictable injuries of trunk pipelines. Later, similar accidental pipeline failures have occurred in Australia, Argentine, Brazil, Venezuela, Iran, Pakistan, Saudi Arabia, Canada, and the former Soviet Union.
Since the middle 1990s, stress corrosion has become one of the key factors of technical safety and reliability of Russian trunk gas pipelines. In 2000s, stress corrosion has spread over the territories of Western Siberia, Urals, northern and central regions of Russia. Quantity of accidents has run up to 17 per year. In 2004, stress corrosion was for the first time traced at the process pipelines of compressor stations. At that period, Gazprom has created a Coordination Council to work out measures for preceding stress-corrosion accidents at pipeline mains. On the Council were deputies from different Gazprom departments, Gazprom VNIIGAZ LLC, and more than twenty other research institutes including the foreign ones. Complex measures embracing the inline pipe inspection, re-sealing, and repairs of the pipelines helped to decrease number of accidents caused by stress corrosion. These measures were realized with scientific support of the Gazprom VNIIGAZ LLC.
Modern economic challenges rise profile of tasks to operate the pipelines subject to stress corrosion cracking efficiently, and to allocate budgets of technical diagnostics and repairing of pipelines rationally. So physical and chemical modelling of stress corrosion based on fundamental scientific studies is quite topical now. Chiefly, the reasons for the intense interest to the named questions are the disadvantages of the classical approaches to assessment of pipe resistance and durability including an idea of homogeneity of pipe metal, absence of criteria of crack stabilization and estimation of an effect of a corrosive medium on kinetics of stress corrosion. Regarding the universal mathematical apparatus of the fracture mechanics, it is important that the accuracy and validity of design models for calculating life cycle (performance) of pipelines are mainly provided by application of empirical equations acquired after serial tests of a pipe metal in conditions close to the working ones.
This collected book is a prospect of modern domestic and foreign views on origination and evolution of stress-corrosion cracking in pipe steels within the near-neutral electrolytes. Sixteen included articles highlight laboratory modelling of the main stages of corrosive-mechanical degradation of pipes as parts of active gas mains, as well as modelling of the quantitative effects which environmental parameters, loading conditions, and properties of pipes exert over the process of stress-corrosion cracking, including the critical values and compositions of the mentioned factors which will stop this process. Authors also demonstrate outlooks for computer simulation of stress corrosion cracking and its software realizations in respect to the tasks of pipeline operation and repairing.
The papers composing this collection were presented Russia in 2018 at the IV International Scientific and Technical Seminar “Improvement of reliability of main gas pipelines subject to stress corrosion cracking” which embraced participants from 28 domestic and 7 foreign companies (Germany, China, Poland, Korea, and Israel), in Germany at the “Pipeline Technology Conference – PTC 2019”, and in China at the “Petroleum Tubular Goods, Equipment & Materials – TEC 2019” conference.
Revealed information could be interesting for research workers and practitioners employed in scientific and industrial companies of gas and petroleum specialization. It will be also useful for students and postgraduates from correspondent universities (inter alia these materials could be applied for compilation of career progression programs).