Trapping Pigs

With the natural gas activity in our area, the term "trapping a pig" takes on a different meaning. We have two natural gas gathering pipelines intersecting on our property  and part of the routine pipeline maintenance involves sending a "pig" through the pipeline to push out condensate (water, sludge and other liguids). The pig is inserted into the pipeline via a "pig launcher" at a valve assembly and the pressure of the gas flow moves the pig along a section of the pipeline until it reaches a "pig trap". The arrival of the pig is signaled by a red pop-up disk on the trap.

Natural gas continues to flow through the pipeline after the pig is caught in the trap. The pig is removed from the trap by opening/closing valves to force the natural gas to by-pass the trap. With the valve to the pig trap closed, a vent valve is opened to reduce the gas pressure (1,100 PSI) in the trap.


Once the gas pressure in the trap is released, a door on the trap can be opened and the pig(s) removed.

Pipeline Construction

Still lots of activity at the pipeline valve site on our property. The crew is cleaning the "Pig Launcher" after it received a cleaning "pig" to remove scale and rust from the 20 inch pipeline.


The cleaning "pig" that was send through the pipeline.



Loading a foam "pig" into the launcher.



Workers check and adjust the pressure in the pipeline to push the "pig".



A worker releases pressure from the pipeline. A light blue stream of compressed air can be seen venting from the top of the pipe.



Workers torque the bolts on a flange.

Pipeline Construction

The welding crew continued to prepare the "pull-back" sections of the Wilmot Pipeline for leak testing. The team welding an end on the pipeline section.



Close-up of the special torch used to cut the pipe.



A couple of the ends welded on the pipeline for testing.



Before the pipeline ends were welded on, a pipeline "pig" was inserted into each section of pipe. A pipeline "pig" is a device that is moved through the pipeline by the flow of gas or fluids.



A photo of one of the "pigs" used for leak testing.