CHARACTERIZATION OF THE ACCURACY OF THE MFL PIPELINE INSPECTION TOOLS

Magnetic flux leakage (MFL) intelligent pigs are the most common tools used for pipeline inspection. But, the MFL inspection results are subject to various sources of uncertainties which must be quantified and accounted for in the integrity assessment of the inspected pipeline. A series of pull-through tests (PTT) of seven MFL tools from four service providers was performed on a 12-inch diameter pipe containing preexisting internal corrosion defects of various length, width, and depth, and located in a variety of circumferential and longitudinal positions. The results of these tests are used to quantify the detectability statistics and the sizing uncertainties of the different tools for future use in developing calibrated probabilistic models for reliability based inspection, quantitative risk assessment and life extension studies for pipelines.