The accuracy of an inline inspection (ILI) tool such as a Magnetic Flux Leakage (MFL) is
affected by the amount of black powder in the pipeline. Parameters such as the ILI tool
signal strength, speed, girth weld readings, rotation, and inclination are affected
resulting in inaccuracy of the ILI tool reports. The analysis of two subsequent ILI run
results may also be affected due to erroneous conclusion that the corrosion depth may
be getting worse when in fact the tool is only reporting more accurate readings of
existing deep corrosion as the line is cleaned of black powder. Thus, field verifications
of the ILI run becomes very important to determine the accuracy of the readings and the
affect of the black powder. However, field verifications are an expensive exercise
especially if all the reported readings must be excavated for inspection. The bottom line
is that the effectiveness of the pipeline validation operation using an ILI tool becomes
critical given the effect of the black powder especially if the reported data is
misinterpreted.
Keywords: black powder, sales gas pipelines, moisture content, sensors lift-off, MFL
run accuracy.