Video inspection and internal weld scanning
Author : Hugh Davies, Head of Sales at Optical Metrology Services,
28 October 2010
When inspecting the inside of pipelines and other subsea structures such as valve manifolds, video inspection can provide close-up views of features that are otherwise very difficult to access. Video inspection enables inspectors to assess a wide variety of features relating to welds, internal corrosion, internal structure, coatings and so on.
Video inspection and internal weld scanning from a single source
Whether onshore or offshore, inspectors need the best possible lighting and video technology, as well as a variety of methods of deploying the video tools inside different types of structures. Optical Metrology Services (OMS) Ltd has a wide range of advanced video inspection equipment. This includes the latest pan-and-tilt camera technology, auto-focus zoom lenses, tractor systems and motorised cable reels.
For specialist weld inspection applications, OMS designs and manufactures unique digital imaging solutions, which can be deployed inside hot pipes during production welding. OMS also offers tool operators and qualified weld inspectors, who provide a full turnkey solution. Bespoke designed and manufactured systems can be delivered to solve the most challenging client inspection requirements.
For ‘reeling trials’, OMS offers video inspection services that can be combined with laser scanning of pipes to provide a combination of imaging and dimensional mapping of pipes or features in 3D.
OMS inspection reports provide comprehensive independent inspection records, which can include still images, video records, interpretation and analysis.
OMS clients can access the best technology and skilled, experienced operators to deliver the best possible video inspection in challenging pipeline engineering applications. Whether the application is in QC, standards compliance, or in special projects, OMS delivers the best solution.
Internal weld scanning
In oil and gas pipes, the quality of the root pass of a weld is critical to the structural integrity of the girth weld. Oil and gas companies therefore have stringent inspection requirements for checking welds. However, few if any tools currently exist on the market that can perform this kind of work. Welding of clad pipe is especially challenging and requires accurate measurement of the weld area in order to ensure zero defects and to avoid the delay and cost of a weld cut out later in the welding process.
Using its groundbreaking internal weld inspection system, in combination with video-based inspection systems, OMS offers customers comprehensive inspection services for checking the internal size and shape of girth welds on pipes that are destined for use in deepsea subsea oil and gas applications.
The Internal Weld Scanning Tool is a unique system that internally scans welds inside pipes, both visually and dimensionally, enabling the quality of the root weld to be assessed quickly and confidently. The tool is available on a service contract or rental basis, with a trained OMS inspector.
The service is available both onshore and offshore at different stages of the pipe welding process. The internal weld scanning tool can be used on corrosion-resistant alloy-lined pipe to identify sour (aggressive) ingress points, in both clad butt-weld and clad weld inlay applications. The tool can also be used to improve weld procedure development efficiency and to check the root weld and geometry before next passes are deposited. The technology provides similar uses in fatigue-sensitive applications (SCRs) where the pipe is subject to higher dynamic stresses.
Using OMS’ internal weld scanning service, a wide range of weld features can be detected, including root penetration, root concavity, cracks, lack of penetration, discolouration, oxidisation, surface porosity and burn-through.
The Internal Weld Scanning Tool can be mounted to a purge dam, with an integrated camera for positioning and inspection. Pipe can be inspected whilst it is being spooled onto a pipe laying vessel or during stalk fabrication/tie-in. Here, the tool is retrieved using a winch and wire system, with weld positioning controlled by a camera and precision motorised system.
The service includes integrated analysis software, which enables the documentation and interpretation of internal weld features, as well as the measurement of cross-sectional data. Scanning a typical 10-, 12- or 14-inch diameter pipe takes around 45 seconds in total. Once the automated scanning of the root weld is complete, the software enables the user to identify the features of the weld and measure them. Cross-sections around the weld, for example, can be chosen and the main features of the weld then measured.
The software is also a traceability tool. Inspectors can choose cross-sections around the pipe at regular angles and log any defects as they are found. The software automatically records all measurements, as well as typed comments from the inspector. This information, including sample images and cross-sectional profile data, can then be archived. Logged data can be directly imported to Microsoft Excel as part of a weld inspection record.
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