A random ultrasonic thickness gaging method is used for the assessment of pipeline technical state (p. 188.8.131.52. of GD 39-132-94 "Oil Field Pipeline Maintenance, Audit, Overhaul and Screening Regulations"). Statistical processing of results is conducted in accordance with the "Prediction of maximum corrosion penetration and a time period before transparent defects show up, based on ultrasonic thickness gaging" Methodological Instructions.
According to the documents listed above the diagnostics of the pipeline technical state consists of the following stages:
Delimitation of pipe parts with homogenous operating conditions
Determination of control points for thickness gaging
Pipe wall thickness gaging at control points based on a special technique
Statistical processing of the results. Determination of corrosion damage distribution regularity and parameters.
Prediction of a maximum corrosion penetration at control points based on corrosion damage distribution regularity.
Additional works are conducted on field corrosion control units with the use of witness samples and electrochemical sensors:
Assessment of types and average rate of corrosion according to field corrosion control units
Assessment of pit corrosion rate
Determination of predictive pit corrosion rates according to a special method based on witness sample profilometry using a metallographic microscope
Assessment of maximal rates of corrosion. Determination of a maximum life period of objects.
To issue a conclusion as to the pipeline technical state, the following measures should be taken:
Detection of corrosion-hazardous pipe parts based on corrosion-hydraulic calculation using the "Extra" software bundle.
Ultrasonic thickness gaging
Installation and withdrawal of corrosion control units
Statistical processing of the results. Issue of conclusions with detailed substantiation.
We deliver and install corrosion control units. On completion of works the Customer retains ownership of the units and may use them for further corrosion monitoring activities.
Technical diagnostics of pipelines can also include:
- monitoring of metal mechanical characteristics
- monitoring of pipeline hydrogenation with the use of removable electrochemical probes
Such diagnostics is aimed at the prevention of damages caused by metal hydrogenation.
We have a license for technical diagnosing and monitoring of equipment and materials using nondestructive methods. License #10O-02/6347 of 25.07.97 issued by the Russian Federal Committee for Mining and Industrial Supervision