Failure in gas industry is an abnormal operation of a technical facility as a result of improper change of its parameters or settings under the influence of physicochemical, external mechanical, climatic or other factors. Technical operation failure brings a facility into a state of breakdown, preserving (in some cases) its working capacity, unlike an accident. Various subsystems of a pipeline as a technical facility influence its working capacity to various degrees. Abnormal operation of a linepipe occurs as a result of pipes or welded connections failure. Low quality of trench or gravel construction operations on the first stage of operation is one of the main reasons for pipeline failure. Moreover, this type of work influences the welding connections reliability to a high degree (failure possibility is 42 per cent for pipe metal and 64 per cent for welding connections), though by the fifth year of operation these factors practically don’t have any influence anymore.

The main reasons for offshore pipeline failures are as follows:

  • corrosion – 50 per cent;
  • mechanical damage as a result of external effects – 20 per cent;
  • damages by storms and landslides – 12 per cent;
  • other reasons – 18 per cent.