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GLOBAL MTM Technology

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GLOBAL MAGNETIC TOMOGRAPHY METHOD

This unique proprietary method of pipeline inspection is based on the inverse magnetostrictive effect (Villari effect) - the change of the magnetic susceptibility of a material when subjected to a mechanical stress. Method uses “natural” magnetization of the ferrous pipes by magnetic field of the Earth.

Figure 1. Magnetic field in the absence of metal defects

Magnetic tomography charts the attributes and characteristics of pipe sections by registering and analyzing changes in the magnetic field of the pipeline. These changes are related to stress which in turn are related to defects in the metal and insulation. Magnetic measurements data is collected from the ground surface and anomalies detected are a function of stress, mechanical loading and structural changes in the metal.

Figure 2. Measured magnetic field as it is recorded by magnetometer device

Magnetic tomography does not measure the dimensions of geometric defects alone but instead it measures the stress caused by these defects and identifies their character, location and orientation in accordance with the location and orienta tion of the area of stress. Linear and angular coordinates of flaws in the metal and coating are defined within a tolerance of +/-0,25m.

Figure 3. Processed measurements allow detection of flaws in the pipeline.

Measure Stress Not Geometry

GLOBAL MTM determines the comparative degree of danger of defects by a direct quantitative assessment of the stress-deformed condition of the metal. Conventional surveys only measure the geometrical parameters of a defect. Their subsequent calculations to assess the impact of the defect on the safe operation of the pipe do not take into consideration the stress caused by the defect. Therefore conventional surveys may fail to detect dangerously stressed areas of the pipe or, conversely, classify a defect as one which requires urgent attention when, in reality, the stress level may be low and the defect presents no immediate threat to the operation of the pipe. Since GLOBAL MTM directly measures the stress caused by defects it is an inherently more accurate guide to the safe operation of the pipeline than conventional survey methods.

GLOBAL MTM Identifies and analyzes magnetic field anomalies in areas with stress concentrators due to:

- Defects or changes in structural conditions (such as metal loss, cracks, dents, lamination and inclusions)

Corrosion caused defectDentInsulation defect

- Excessive mechanical stress caused by erosion, seismic activity, or third party damage
Seismic related defectThird party damage

- Combination of the above

The method has the following advantages:

- Applicable for the unpiggable pipelines or other objects where in-line inspection method is inapplicable. This objects include but not limited to:

- compressor stations pipelines;
- pipeline inclusions;
- water-supply pipelines in cities
- GLOBAL MTM doesn't require any preparation of the pipeline for testing such as cleaning, opening the pipe, or stopping pipeline operation. Magnetic field measurements are performed with pipeline operating as usual.
- Doesn't require magnetizing of the object's pipes;

- Method detects defects of various types including long crack-like defects of the pipe and the welding;

- Doesn't have limitation on the diameter, configuration, and method of protection of pipelines tested. These include:

- change of pipe diameter and wall thickness,
- pipeline turns and their directions,
- transported product (e.g. gas, oil, or water)
- pressure inside the pipline
- pipeline protection (e.g. cathodic protection, etc)

Method evaluates the degree of danger of defects by the level of concentration of mechanical tensions rather than defect geometry (e.g. length-width-depth)

Method is optimal for running a database on condition certification of objects of any length and any monitoring period

Method guarantees minimal customer resources use for monitoring preparation and repair works such as:

- reduces work volume and total costs of pipe access works;
- greatly reduces time of full diagnostic - repair evaluation - repair planning - repair cycle;
- gives pipe corrosion prognosis and estimates levels of tense-deformed state of the pipeline under current operating conditions.

GLOBAL MTM for Offshore Facilities

The GLOBAL MTM technology has been further developed to emcompass submerged pipelines.

Figure1. Principle of operation of the device - it measures magnetic field distortion in the presence of metal defects.

Figure2. Underwater pipeline testing device is being prepared for submerging.

The device features magnetic field detectors, several remotely operated video cameras, light sources, and propelling devices.

Figure3. Magnetic field sensors (1), remotely controlled cameras (2), propelling devices (3), and light source (4) are parts of the unit necessary for successful operation.

It is launched from the mother ship but performs maneuvers using its own propelling devices.

Figure4. Mother ship with submerged unit on the route.

The unit is controlled by operator from inside of the mother ship.

Figure5. GLOBAL MTM for underwater operator workplace during pilot testing.

Operator navigates the device and checks for the objects that might prevent GLOBAL MTM for underwater to gather the data.

Figure5. GLOBAL MTM for underwater Operator Console during the testing process.

GLOBAL MTM Guarantees

GLOBAL MTM Guarantees high Probability Of anomaly Detection (POD) level. GLOBAL MTM Technology reliably reveals anomalies related to metal defects of any type within interval of local mechanical stresses in anomaly zones of 0,30÷0,85 Specified Minimum Yield Strength (SMYS) with reliability POD = 80 % for 97% of the pipeline length.

Declared value of POD for GLOBAL MTM is not less than 80% at mechanical stresses in defective areas (or features of the object) within the range of 30-85% SMYS.

GLOBAL MTM General Limitations

The GLOBAL MTM Technology has limited or no application if one or more of the following conditions are true:

- High level of residual magnetization of pipelines;
- Stresses in the area of anomaly exceeding yield strength;
- Presence of magnetic masses between magnetic field sensors and a pipeline.

Diagnostics devices

Magnetometer SKIF - MBS

Of late a contact method of pipelines technical condition diagnostics based on metal magnetic memory (MMMM) which utilizes magneto-elastic and magneto-mechanic effects was developed. Parent metal and welds areas are brought to light in excavation pits according to residual magnetization rate with recording of stress concentration lines on top of objects under examination characterized by a field maximum gradient at these lines crossings.

A non-contact magnetometric method is a new method of technical condition estimation based on exposure of flaws whereabouts owing to magnetic conductivity change registration resulted from changes in stress caused by mechanical loads or structural changes in pipeline metal (pipe deformation, internal or exterior corrosion, sags, landslip loads, etc.). A similar principle underlies exposure of flaws via registration of satiation magnetic fields by way of a magnetic flaw-detection device application. Metal flaws exposure efficiency thereof is comparable with in-line flaw detection and is not less than 75%.

Thereto a non-contact scanning Magnetometer “SKIF” of MBS product line (MBS-03, MBS-04) – which is in a sense an “out-line” flaw detector – was devised and successfully approved.

Certificates:

Certificate of approval of types NON-CONTACT SCANNING MAGNETOMETERS MBS-04 “SKIF” #30786-05 of 26.12.2005

Certificate of conformance by permissibility #6639426 of 23.11.2005

The method enables

1) To fix position of metal flaws and insulation coating from the ground surface without pipe exposure (in linear and angular coordinates) with accuracy ± 0.25 m.

2) To estimate the nature of pipeline metal defects, to monitor their growth and build a database on its actual technical status.

3) To perform pipeline systems certification with entries of data on the detected flaws position in absolute geographic coordinate system (GPS), specification of a pipeline axis and laying depth.

Route-locator Poisk-A

- Finding location and laying depth of underground service metal pipelines of large and small diameters, power and telephone cables, even if they run parallel to each other irrespective of the cathodic protection presence and on the background of interferences caused by power transmission lines, tram and trolleybus lines.

- Fast and reliable inspection of territory before excavation works.
- Exact determination of pipeline location to prevent damage of insulation coating during excavation works.
- Location of intersections of pipeline with any alive cables.
- Finding of pipeline or cable nearby other service lines including overhead power lines.

«POISK-AMS» set service conditions: air temperature from -30 up to +50°C, relative humidity up to 98% at +20°C, atmospheric pressure 84-106,7 kPa.

Odometer ODA-03

Portable odometer ODA-03 of «ODA» series is intended for distance measurement along a route of extended engineering structure, in particular, pipeline, on cross-country, with the purpose of fixation the linear coordinates (fixations on locality) of defects, which have been revealed during the in-line, non-contact magnetometric or other diagnostic inspection; features of a route: ground line structures, river crossings, roads, ravines, etc.

Portable odometer ODA-03 can be used as well for marking the longitudinal coordinates along an underground pipeline axis for completion of a database for the process of certification, as a unit of pipeline route-tracer "POISK-AMS" or other route-tracer set with function of laying depth measurement.

- Portable
- Minimal weight
- In the shock-resistant case
- Is simple in operation

Transkor Operation Workflow

This page describes what happens when contract with Customer is already signed and the Transkor get to work with the Customer's inspection object.

1) Transkor gets technical description of the object and goes to the object's location with representatives of Customer to take the necessary measurements

Comparison
with Other Diagnostics Methods

Here's how GLOBAL MTM fares in comparison to other pipeline testing methods.

Comparison with ultrasonic pipeline diagnostics and in-line inspection:

Defects or damages of underground pipeline Ultrasonic diagnostics In-line inspection GLOBAL MTM Technology
External corrosion +/- + +
Internal corrosion +/- + +
Fatigue cracks and SCC +/- + +
Insulation damage - - +
Manufacturing defects +/- + +
Land slides - - +
Leakages - - -
Illegal incuts - +/- +/-
Third-party damage - - -

Legend:

- Method is not effective +/- Method is not effective enough or technological enough + Method is effective
Cutting edge Technology

This unique method of pipeline inspection makes use of “natural” magnetization of the ferrous pipes.

Awards and Accolades

GLOBAL MTM was exhibited along with the set of devices at multiple conferences and exhibitions worldwide.