A new generation of geometry sensor for ILI tools has been developed. This sensor provides highly accurate geometry data of the internal pipe contour. The technology uses the benefits of a touchless distance measurement in combination with the advantages of a mechanical caliper arm. The complementary interaction allow the measurement of accurate data under demanding operational conditions. The geometry sensor technology can be combined with a navigation unit and the high resolution MFL inspection technology on so called multi-purpose ILI-tools. The merging of different inspection tasks on a single tool is an economic solution to create and add to an ILI-database for integrity management. Field experience with this new technology will be discussed, based on more than 500 miles inspected pipeline. Most inspections were performed in the US and Canada. The operational performance of the sensors justified the new design.

Battelle has developed dual field magnetic flux leakage (MFL) technology for the detection and characterization of mechanical damage to pipelines. The basic principle involves the use of a high magnetic field between 140 and 180 Oersted (11.1 to 14.3 kA/m) and the use of a low magnetic field between 50 and 70 Oersted (4 to 5.6 kA/m). At high magnetic field levels, the flux leakage signal is primarily influenced by changes in the geometry of a pipe wall. At low magnetic field levels, the MFL signal is due to residual stresses and metallurgical changes as well as geometry changes to the pipe caused by mechanical damage and wall thinning. A decoupling signal processing method developed by Battelle is used to isolate the portion of the mechanical damage signals due to metallurgical damage and residual stresses, which allows the characteristics of a dent-gouge feature to be more clearly differentiated. The decoupling method involves first scaling down the high field signal to the level of the low field signal, and then subtracting it from the low field signal. This produces a decoupled signal that is primarily influenced by the residual stresses and metallurgical changes caused by mechanical damage. Rosen has developed a tool to test the dual field technology and is evaluating tool performance by running the tool in a 30 inch diameter pipeline segment. The tool itself is composed of three separate modules coupled together: a high field unit downstream of a low field unit which is downstream of a caliper arm unit that is used to detect and characterize reductions in the internal diameter. The general and magnetic design of the tool, along with the scaling algorithm is discussed. Results from a pull test in a pipe section with dents whose geometry has been independently characterized are also discussed. This work is partially funded by the U.S. Department of Transportation, Pipeline and Hazardous Materials Safety administration (DOT PHMSA) and the Pipeline Research Council International, Inc. (PRCI).

Large diameter pipelines of 48” and 56” traverse the Ukraine. These pipelines are the life-line for the Russian gas transit to high demand European Union (EU) markets. The high economic impact to several European regions and the complicated legislation of these pipeline systems reduces the operators’ ability to change operating conditions to better suit in-line inspection. Ukrtransgaz requested a reliable and compact inspection tool able to negotiate 1.5D bends. Thirty degree (30°) mitre bends and demanding elevation changes in the range of 1500m (4921ft) also had to be considered. The high economic impact of the pipeline systems did not allow Ukrtransgaz to reduce the high flow speed of the gas, which is more than 10 m/s (22.2mph), during the inspection. In combination with the before-mentioned elevation profile, an inspection tool with active speed control was required. As part of the planned re-assessment survey, an XYZ mapping inspection relying on an inertial navigation system was also required. The inspection solutions provided by ROSEN were multipurpose tools providing MFL technology, an XYZ mapping module and active speed control in a single body. It will be discussed in this paper how the miniaturization of electronics and computer technology is not only a key point for small diameter tools, but also essential to meet the demanding targets of inspecting large diameter gas lines. Breaking with the paradigm, that large pipe provides enough internal space, was the basis in accomplishing the demands of the operator.