Large Savings For Oil Companies
20 March 2003 15:48
A tool, which pumps itself into the pipeline while it’s mapping both the bore profile and the thickness of the pipe. It stops on selected positions in the pipe, and perform a sweep over the pipe circumference looking for cracks or LOF defects in i.e. welds. Initially this sounds impossible, especially considering that this can be performed over several thousand meters of pipelines.
Initially nick named after the project it was developed for, namely the ‘Tune’ tool, it has been subsequently re-branded as the Total Integrity Inspection Tool (TIIT).
AGR EmiTeam AS developed this tool based on the existing Pipescan technology, which has been in use worldwide for several years. The Pipescan tool is a tethered, high resolution Ultrasonic inspection device used for corrosion mapping and geometrical surveys of pipelines. By implementing a special probe carrier for volumetric inspection of welds and pipeline installations, it became possible to inspect areas previously not accessible for existing inspection technology.
The tool was developed in conjunction with a large offshore project, a major oil company in Norway found it necessary to carry out a closer examination of the quality of certain weld connections. The main objective of this examination was to provide better input data for ECA (Engineering Critical Assessment) analyses. AGR EmiTeam AS was contacted, and was offered the opportunity to develop a tool that could provide for these needs.
The AGR EmiTeam AS TIIT incorporates both ultrasonic, video and TOFD (Time Of Flight Defraction) technologies thereby making it one of the most advanced inspection tools on today’s internal pipeline inspection market. In addition, the TIIT tool will soon boast laser capability as well.
The TOFD method can provide the necessary data for ECA. However, prior to the TIIT TOFD had never been used internally in sub sea offshore risers and pipelines before. TOFD provides the possibility of determining the height of defects greater than 2 mm as well as detecting defects that are a fraction of a mm large within a weld.
The new Tool was faced by great technical and inspection challenges. During the course of inspection the tool passed 9 x 3D bends and travelled more than 300 meters down and out upon the seabed. The pipeline was 10/12”. The propulsion of the tool was solved by a self- propelled differential pressure pig, which operates by pumping water across a seal. The positioning of the tool over the welds were controlled by axial motor on the transducer assembly, and verified by video camera.
The inspection results gathered by the tool provided the client with the necessary information in order to perform a safe assessment of the integrity of the pipeline.
Whilst it is typical for infrastructure owners to calculate the cost of inspection as a pure cost, the quality of data captured by the Total Integrity Inspection Tool allowed the customer to make important decisions with respect to the continued serviceability of the pipeline. In this case, the continued operability of a pipeline which may have otherwise well been replaced. The comparative cost comparisons were simply academic!
For more information on this company:
AGR Pipetech - Pipeline Inspection and Defect Detection
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