Page 315 - Pipeline Pigging Technology

Pipeline Pigging Technology

Fig. 12. The stripper technique being used in the 10-in test loop.
pipeline as shown in Fig. 12. The system proved its capabilities over the full
length of the pipe (400m) and several 3D bends (up to 360°).
We assume that the current cable length (2000m) is the only range limit for
this technique when applied in an almost-straight pipeline. Probably the
combination of bends and cable length sets the practical limits, and this has
to be investigated further. An 8-in tool (see Fig. 13) has recently been
completed for a job in 1991. Fig. 14 shows this tool, including the motor-driven
winch.

Self-contained ultrasonic tools

4. The RTD RPIT

In order to inspect an oil riser on-stream, RTD and Shell mutually decided
to build a fluid-propelled ultrasonic pig using the stand-off method, as shown
in Fig. 2; Fig. 15 shows the schematic lay-out of the consequent riser-pipe
inspection tool (RPIT) which was built to the following design specifications:

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