Internal corrosion of steel pipelines is a major hazard in the oil and gas sector due to the high level of environmental costs and implications of spillage of oil or contaminated water. Regular replacement of the pipelines, however, leads to high costs for the operator.
Companies such as Kuwait Oil Corp. (KOC), which is suffering from an increasing presence of hydrogen sulphide in the crude oil it handles, are thus seeking more cost-effective solutions to internal corrosion. One option is to "close-fit" internal linings of polyethylene pipe, which significantly extends the life of the original pipeline. The process works equally well for flow lines and water injection lines.
At the Arabplast Exhibition held in Dubai from Jan. 8-11, Borouge (Singapore) demonstrated how it is helping the industry in the Middle East extend the lifetime of their steel pipelines by internally lining them with durable, corrosion-resistant HDPE.
Borouge teamed up with plastic pipe producer Kuwait International Advanced Industries (KAI) and Anti-corrosion Protection Systems (APS), a specialist relining contractor based in Dubai, to provide a solution to KOC. A "tough" PE100 liner was proposed for an existing steel pipe, which, although it has only been installed a relatively short time ago, is already showing signs of corrosion.
The new highly stress-crack-resistant PE100 grade from Borouge, BorSafe HE3490-LS-H, was applied to achieve the highest reliability. This material provides a much higher resistance to crack growth compared with standard PE100 materials. In notched pipe testing, the performance is reportedly an order of magnitude greater than the 500 hours required by the PE100 specification. Therefore, any defects or scores that are introduced during installation will not develop into cracks, which would otherwise cause premature failure of the lining.
The project kicked off when a section of an existing steel water injection line is decommissioned and removed from the pipeline. This section was then "pigged" to remove the considerable amount of sludge and corrosion products that had accumulated in the bore of the pipe. PE100 pipe sections were delivered to site and the pipe lengths butt welded together by APS and pressure tested prior to insertion. The pipe was then inserted into the steel pipe using the well known "swage-lining" close-fit insertion technique. In this method the pipe is drawn through a smaller diameter die by a winch, which then pulls the pipe through the host pipe. When the winch is uncoupled, the PE pipe tries to return to its initial diameter and forms a close fit with the bore of the steel pipe.
"The process went extremely smoothly. KOC monitored closely throughout the project and were particularly pleased with the high speed of installation," commented Khalfan Al Muhairi, application marketing manager of the pipe business unit, Borouge. "With such a successful project, KOC are now considering working together with Borouge for other new projects in order to extend the lifetime of their assets."—[email protected]