New pipeline inspection technologies unveiled
GE Oil and Gas’ PII Pipeline Solutions is adding new tools to its portfolio of pipeline inspection technologies. The EmatScan CD and MagneScan in-line inspection tools both promise greater efficiency in detecting cracks and corrosion well before a problem arises.
EmatScan CD
This technology applies PII Pipeline Solutions’ Electro Magnetic Acoustic Transducer (EMAT) technology to detect evidence of stress corrosion cracking (SCC) and individual cracks in gas pipelines.
Unlike conventional ultrasonic inspection methods, which require gas pipelines to be filled with a liquid or have the tools run in a liquid batch, EmatScan CD does not require a liquid medium for its signals to reach the pipe wall. This provides operators cost savings by avoiding preinspection preparation and eliminates the introduction of foreign liquids in the pipeline to obtain accurate inspection data.
The system reportedly can detect cracks as short as 1.97 in. (50 mm) in length and as shallow as 0.079 in. (2 mm). It can also detect subcritical SCC colonies before a problem arises, which gives advanced warning on the need to implement an SCC management program and avoids the necessity of performing high-cost, production-limiting hydrostatic testing.
The greater data accuracy afforded by the tool reportedly allows critical SCC and other cracks to be effectively isolated and evaluated in order to prioritize repair activities and minimize the amount of digging and disruption to a pipeline’s normal operation. The tool also identifies specific types of cracks, such as longitudinal fatigue cracks, hook cracks, lack-of-fusion cracks, and cracks in or adjacent to the seam weld.
The company states that by making repeated inspection runs with the tool, an operator can determine growth rates and mechanisms associated with subcritical crack colonies, which assists with the overall crack management strategy of any gas pipeline.
MagneScan
PII Pipeline Solutions also recently unveiled its next-generation MagneScan technology, an improved version of previous MagneScan versions that uses magnetic fields and various sensor combinations to detect corrosion and other faults in pipelines.
The tool uses the magnetic flux leakage principle to locate metal loss. As the tool moves through the pipe, permanent magnets magnetize the internal pipe wall via wire brushes that contact the wall. Flux density is given to the point of saturation, and any change in pipe wall thickness results in a disturbance of the magnetic field. Sensors read these disturbances and record the data, which is then analyzed to obtain characteristics of the flux leakage to establish the dimensions of the anomaly in the pipe.
The tool also possesses a ring of secondary sensors that discriminate between internal and external metal loss, odometer wheels that log the distance traveled, an internal pendulum that records the orientation of the tool in the pipeline, and a time-based marker system that logs the tool’s time of passage.
The newest version of the tool boasts improved magnetizer design and more advanced sensor technology over the previous generation. The tool is also equipped with a fully integrated high-resolution caliper, EMAT sensors to measure wall thickness, and geographic information system (GIS) mapping technologies for improved data alignment. The new MagneScan can detect corrosion at 5% of wall thickness with 90% probability of detection, and the depth-sizing accuracy is +/? 10% at 90% certainty.
The company states that the tool is smaller than previous generations, lighter, and easier to manage. The unit is capable of navigating and inspecting tight bends and restrictions, including back-to-back bends with a 1.5 D radius (i.e., the bend is 1.5 times the nominal pipe diameter). The tool is also easier to launch and receive without the need for pipeline modifications, and requires fewer field technicians for deployment.
As with previous MagneScan versions, the new tool can be used in any pipeline inspection scenario, including dry or liquid product, onshore or subsea. The new tool will be available for 6-, 8-, and 10-in. lines in select customer markets as of December 2008. The technology will become widely available in core markets beginning in the summer of 2009, with larger diameter versions to follow.