Intelligent pigging of low pressure pipelines

[Kiranpatel]

Does anybody out there have any experience with pigging of low pressure pipelines. We have a problem in that the pipeline operates at very low pressures (2 to 4 bars). The concern is that these pressures might not be high enough to drive the pigs through the pipeline. From memory, I remember that, as a rule of thumb, normal pigs have a 1 to 2 bar pressure drop across the pig. The concern is that with the heavier intelligent pigs, this driving pressure might have to be higher.
Is there anybody out there how can give some operational experience on this subject ?
Regards
Kiran