Pipeline geometry inspection

Pipeline reliability mostly depends on the pipe wall condition. The pipe wall holds the medium internal pressure and withstands external mechanical effects. The design wall thickness calculations are based on the fact the pipe cross section shall have round form. Dents and folds in the pipe wall may cause problems.

All pipeline internal geometry inspections performed in Russia to date have been conducted using measurement systems with a contact sensor in the form of a long spring arm with a wheel and a “paddle” on the end. Such system has a typical measuring element chatter created when the tool moves in the pipeline; besides, the value of the sensor rebound from the pipeline wall is directly proportional to the tool travel speed and at speeds over 3 m/s geometry defects measurement accuracy drops.  And the sensor model significantly impacts the actual defect geometry distortion.  The major disadvantages of the contact system are its high vulnerability to mechanical damages, principally, in pipelines with spacers, and impossibility to use bidirectional configuration allowing running the tool both direct and reverse.

An electronic touchless geometry tool was developed to verify the pipeline construction quality, to identify hidden damages done by a third party. In addition it verifies the pipeline passability for other tools. The electronic touchless geometry tool identifies and measures all possible obstacles and locates them. 

The electronic touchless geometry tool is the least expensive way to provide information about the pipeline internal geometry condition.  The unique touchless measuring system guarantees a full pipe surface circumference coverage achieved due to overlapping measurement sectors allowing using such tool as a bidirectional one.

The measuring system uniqueness is, first, due to the fact it does not touch the pipeline wall and, second, the measurements accuracy is not impacted by pipeline lower generatrix buildups.

A unique touchless geometry measurement sensor unit includes 48 sensory channels combined into 8 measurement units. Each channel makes 100 Hz frequency measurements. It means each sensor individually makes 100 measurements per second.   

The measurement principle is based on multichannel eddy current technology and makes touchless  remote measurements from the sensor surface to the pipe internal wall.

It allows avoiding dynamic impacts during geometry inspection.

Electromagnetic field created by the measuring system does not depend on the pipeline medium type (gas, water, oil, air, etc.) as the difference between these substances magnetic inductivity does not matter. The impact of electric inductivity relates to the mechanical dipper system and correlates by online recalibration. Thus, only ferro-materials such as pipe wall impact the electromagnetic field created by the tool.   

The sensor measurement sector overlap guarantees a full coverage of the pipe perimeter. As the pipeline internals present an accurate faraday cage any disturbances to the electromagnetic measuring system from potential external electromagnetic sources are avoided.