METHOD OF REJECTION AND REPAIR OF UNDERGROUND PIPE LINES Russian patent published in 2017 - IPC F16L58/00 

FIELD: oil and gas industry.

SUBSTANCE: cracks with depth exceeding 0.1 t are detected, where t is the thickness of the pipe wall. The areas of the pipes with cracks detected after non-destructive inspection, the insulation is pre-cleaned, and the cracks are identified by signs of stress corrosion cracking (SCC) and subjected to additional control by determining their depth. If the crack depth is less than 0.1 t, the damage of the pipe is considered insignificant, and the pipe with minor damages is repaired by finishing cleaning the surface and subsequent reinsulation under trace conditions with the use of bitumen-polymer materials containing the SCC inhibiting composition.

EFFECT: extended functionality capabilities characterised by rejection of pipes subjected to stress corrosion cracking, improved reliability and resistance against corrosion cracking under stress of repaired sections of underground pipelines, and improved technological efficiency of procedure for rejection and repair of pipelines.

3 cl, 1 dwg, 1 tbl