Technology of supervising the submerged crossing

Supervision of submerged crossing (SC) is conducted us-ing specific technical facilities. The main and auxiliary branches of SC should be equipped with launcher and catcher stations for in-line cleaning and smart pigs. These are key stages of super-vising the SC using the in-line facilities of technical inspection:

• 1 stage – cleaning the SC interior from paraffin and foreign objects with cleaning pigs. The quality of cleaning should corre-late with recommendations of the companies, which conduct the supervision using the in-line facilities of technical inspection.
• 2 stage – calculating the minimum run-in clearance of the CS pipeline along its entire length. The minimum run-in clearance is calculated by launching a specific cleaning pig – a gauging pig with measuring disks (plates) suitable for the given SC diameter.
• 3 stage – receiving of data regarding the pipeline’s inside geometry along the entire length of inspected SC, launching the geometry tool for the purpose of detecting the geometry faults. The possibility of geometry tool launch is identified according to the existing situation on the SC, considering the pattern of gaug-ing pig’s plate deformation.
  Further inspection of SC walls includes the usage of self-contained in-line smart pigs or devices, used for inspection of crude oil and gas wells on logging cable.
• 4 stage – pulling the logging cable or the wire cable from launcher station to catcher station, using the specific separator.
• 5 stage – identifying the actual high-altitude and horizontal position of the SC, using the inclinometer. 
• 6 stage – defining the density (existence) of ground around the SC pipeline, as well as the av-erage SC wall thickness, using the well gamma-flaw detector.
• 7 stage –measuring the size and geometrical shape of the SC pipeline, using the well acous-tic device. Upon the results of SC inspection, the pipeline’s residual life is calculated, as well as in-dustrial safety examination, registering the results in Russian Federal Service for Environmental, Technological and Nuclear Supervision.

The technology is developed by “VOSTOKneftegaz” together with “Geofizika” and used while inspecting the SC of “Bashneft”, “Udmurtneft” and “Belkamneft” pipelines.

The technology is agree by Russian Federal Service for Environmental, Technological and Nuclear Supervision and approved by the Ministry of Industry and Energy of Russian Federation. 

PARAMETERS, CONSIDERED DURING THE INSPECTION

• Errors of SC pipeline geometry (wrinkling, dents, bellying, swing radii).
• Actual 3D-positioning of SC.
• Existence of bare spots in SC pipeline (according to the density of ground around the pipe-line).
• Interior profile of the SC pipeline.
• Thickness of the SC pipeline wall (corrosion damages).
• Modeling the interior of the SC pipeline.
• Weld monitoring.