VKVC NON PIGGABLE DE-COMMISSIONING ON-Shore
Overview 3 Pipelines 16 ” NB 12km long were installed Parallel in 1980 to transport Crude from Jetty to a tank farm. Rapid Urban development led to the Pipeline ROU being severely encroached. The Pipelines were not designed to be pigged and could not be inspected by Intelligent Pigging. No as built drawing were available. Space constrains ruled out Pig Barrel installation.
In 2013 it was noticed that several houses located in the vicinity of the Pipelines weregetting Oil droplets in their water supply.The authorities ordered the product to be evacuated and Pipeline decommissioned immediately. The initial proposal was to evacuate the product with water however the volume of water required and subsequent disposal procedure ruled out this option. The only solution was to evacuate product with pigs that would negotiate reduced bore valves, miter field bends. As the Pipelines were known to be leaking the pigs were to run at very low pressures. Further leakage was to be avoided.
Procedure VKVC was nominated to decommission the Pipelines on an emergency basis. As no As-Built drawings of Pipeline were available, the valves, bends etc. could not be replaced VKVC team decided to use Gel Pig to evacuate the product. On completion of evacuation to ensure that the Pipelines were clean for decommissioning the line would be cold cut and inspected for any residue of Crude Oil.
VKVC Gel Pigs water based concentrate was manufactured at VKVC Plant and dispatched to site in a controlled temperature cabinet. The Gel Pig concentrate was then mixed at site with water and pumped into the Pipeline followed by Polymer. This was displaced in the Pipeline with Nitrogen and Air. All evacuated Crude was collected in a designated tank. This process was followed for all the 3 Pipelines. On completion of pigging the lines were cut at convenient locations inspected visually and with hydrocarbon detectors. All lines were free from Crude Oil residue. The lines ware decommissioned in record time successfully.