Since the first pipeline transport was built in the late 19th century, many oil and gas pipelines have been constructed and nowadays they are considered as un-piggable.
It is estimated that at least one third of all oil and gas pipelines around the world are considered non-piggable for one reason or another. There is growing tendency in the market to look into the integrity of these pipelines.
From operators’ point of view, continue operating un-piggable pipelines without assessing their real condition constitute immense pressure to ensure the safe operation and to minimize the impact on environment.
According to the availability of information considering costs, environment impacts and risks involved, operators’ recommendations and decisions are different:
- Some decided to build new pipeline systems and demolish the existing.
- Some decided to use newly developed ILI tools that can negotiate un-piggable pipelines.
- Some decided to rehabilitate the lines and transform them into piggable pipelines.
- Some decided to accept the current situation and do remedial actions as required.
The objective of this paper is to explain the methodology of safe and cost effective method to transform un-piggable pipeline systems into piggable. This operation has been developed for safely pigging, de-oiling and demolishing of existing aged pipelines in Kuwait.
The main obstacles were as follows:
- Short radius 1.5D bends.
- Multi-diameter pipelines.
- The lines have never been pigged before.
- Rrisk of existing metal parts and waxes inside the lines
- Un-known valves conditions.
- Un-barred Tees.
- Non availability of Pig Launcher/Receivers.