When developing new hydrocarbon deposits in old fields, problems related to providing operational reliability of process pipelines built using conventional steels and technologies, which were used for this climatic zone, and formerly known characteristics of recovered hydrocarbons, occur increasingly. It was found that one of the reasons of premature failure of new transport networks consists in difference between existing operational conditions and parameters laid in the design, based on which materials and technologies for oil field development were selected. These unconsidered differences were realized in pipelines from steel 09G2S as a synergistic effect, which resulted in sharp increase of corrosion and erosion damage rates for pipes themselves, various pipeline structural elements (connecting parts), as well as their weld joints. In conditions of high flow rates of gas-condensate mixture with variable density, stable turbulent motion is formed in a pipeline system, which results in rill-washing corrosion in pipes, that is increased with carbon dioxide corrosion; at that flow breakaway in metal “leak” areas in root sections of nonrotational ring erection joints or sharp change of flow motion angle in branch sleeves and elbow bends by 900 results in increase of corrosion-erosion wear, intensity of which starts depending directly on corrosion and mechanical characteristics of the base metal, weld joint areas metal, level of residual welding stresses; in single pipeline areas it could reach 3-4 mm/year. The paper shows mechanisms of corrosion-erosion failure of steel 09G2S and its weld joints, as well as it presents recommendations on performability increase for process pipelines under these operational conditions.
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