In – line inspection

In-line inspection being a highly efficient and informative technique of technical diagnosis plays a key role in the system of trunk line diagnostic study.

In-line inspectionn (ILI) is the complex of technological operations implemented by “intelligent” pipe flaw detectors (inspection pistons) sent through the pipeline.

ILI makes it possible to carry out inspection all along the linear portion of gas mains, to detect, identify and characterize different types of damages and defects.

CJSC “AMT” is an official representative of the diagnostic company ROSEN Europe BV (Netherlands) and is granted the exclusive right to conclude contracts for the use of ROSEN Europe BV equipment and technologies at Gazprom and its affiliates.

Using ROSEN diagnostic tools and technologies CJSC “AMT” successfully performs pipe flaw detection operations both of standard pipeline sections and highly engineered sections unsatisfying testability

Standard pipeline sections Standard pipeline sections
  • presence of sender/reception chambers for pipe pistons;
  • permanent diameter throughout the area;
  • equal boom drift pipe fittings;
  • turning radius of above 3D
  • absence of sender/reception chambers for pipe pistons;
  • nonequal boom drift diameters;
  • nonequal boom drift pipe fittings;
  • turning radius of 1.5 D;
  • low pressure;
  • presence of straight cutting-ins up to 80 mm;
  • underwater crossings;
  • subsea pipelines


  • cleaning;
  • profilemetry;
  • magnetic and ultrasonic flaw detection.


  • cleaning;
  • profilemetry;
  • magnetic flaw detection.

Using standard ILI equipment

Using specialized ILI equipment

Additional surveys:

  • EMAT survey to assess coating condition;
  • EMAT survey to identify stress corrosion cracking;
  • Compilation survey of pipelines by geometric pistons of increased accuracy followed by VAT calculations.

ILI of standard  pipeline sections

CJSC “AMT” uses pigs-flaw detectors on the basis of magnetic and ultrasonic non-destructive methods of testing, navigation pigs, as well as pigs-flaw detectors with integrated technologies of electromagnetic-acoustical (EMA) transformation.

Integrated estimation and technical state prediction include the following principal activities:

  •   Building of pipeline spatial database to map diagnostic, design, executive and in-line technical data using geodesic survey and other available information.
  •   Reduction of diagnostic, design, executive and in-line technical data to interrelated references and spatial-based mapping.
  •   Damage assessment and their accumulation dynamics in pipeline sections (elongation pattern of different defects, distribution of metal defect concentration in pipes).

The technology of electromagnetic and acoustical transformation makes it possible to receive reliable information on crack-like pipeline defects (stress-corrosion cracks, fatigue cracks, external longitudinal cracks at the weld), and also to assess outer insulation coating. 

The use of navigation pigs is conditioned by the necessity of pipeline mapping and area-tie of pipeline specifics and defects. The inertial measuring system components of which are gyroscopes and accelerometers registers pig movement through the pipeline and the system of markers adjusted to the known GPS reference points allow to tie specifics and defects to the area. 

At present in view of the available diagnostic equipment it is possible to perform ILI of the pipeline sections ranging in diameters from 159 mm to 1420 mm.

ILI of highly engineered pipeline sections

The design of most active pipelines does not meet the ILI testability requirements, in particular, pipelines with pipe bends 1.5D, of non-equal boom drift diameters or with non-equal boom drift pipe fittings, low pressure pipelines, pipelines not equipped with stationary sender-receiver chambers.  

The use of conventional pipe diagnostic equipment is limited by increasingly cost-consuming improvements of sections and their restoration. The use of specialized pipe diagnostic equipment able to meet pipeline design specifics can be the alternative.

For many years CJSC “AMT” performs the inspection activity of  “Gazprom” pipelines structurally not satisfying ILI requirements using a special diagnostic equipment of ROSEN Europe BV. 

Now capacities are available to carry out PTD operations for the following highly engineered pipeline sections:

  • pipeline sections with return bends 1.5D for diameters 159 – 1420 mm;
  • pipeline sections of non-equal boom drift diameters and non-equal boom drift pipe fittings for diameters 219/273 mm, 273/325 mm, 325/377 mm, 325/426 mm, 426/530 mm, 530/630 mm, 720/820 mm, 720/1020 mm;
  • pipeline sections under low operating pressure (12-25 MPa) for diameters 219 – 530 mm.

CJSC “AMT” in cooperation with ROSEN Europe BV is always ready to consider any possibility of manufacturing the equipment of any standard sizes not mentioned above provided the contract is signed.