BP Norway shortened an extremely expensive production shutdown when one of their pipelines cracked. FORCE Technology’s corrosion and inspection expertise paved the way for an unorthodox solution.
In 2004, BP Norway experienced an operator’s nightmare when an important pipeline from Tambar to Ula cracked. The crack was caused by incompatibility between the pipeline material and the external corrosion protection in combination with upheaval buckling. The entire export from Tambar was halted and remedial actions had to be determined fast.
Can’t hold fluids without help
It was important to find a temporary solution, which would provide transport of the Tambar production. The apparent solution was to make a tie-in to the existing pipeline from Ula to Gyda, the UGIP line. However this line is in carbon steel and is basically not suitable for transporting the Tambar multiphase production. The corrosion rate of the Tambar fluids in a carbon steel pipeline is extremely high before addition of corrosion inhibitors. This meant that proper control of the corrosion inhibitor would be of utmost importance if this solution was to be used.
Must be monitored closely
BP used FORCE Technology’s expertise to perform the necessary evaluations and to verify the soundness of this temporary solution. FORCE Technology put together a team of experienced specialists within pipeline operation, corrosion, materials and inspection.
In order to assist with the verification, FORCE Technology used the CorPos simulation software. This tool calculates corrosion profiles for entire pipelines and takes into account all parameters which affect the corrosion conditions. Based on the simulations, FORCE Technology found that, although the operation is very dependant on proper corrosion inhibitor control, the UGIP line can be used as a temporary solution for exporting the Tambar production.
Successful temporary solution
Based on FORCE Technology’s evaluations and recommendations, BP decided to use the UGIP line for transporting the Tambar production to Ula. This decision reduced the shutdown to 3-4 months instead of 1-2 years. The pipeline has been in operation for Tambar since December 2004.
The on-going corrosion status is verified by monitoring equipment at Ula and Tambar. The monitoring shows that the corrosion in the UGIP pipeline is under control. An intelligent pig survey was also conducted 9 months after the tie-in. No signs of corrosion were detected.
”We chose FORCE Technology to assist with these evaluations due to their core competency within corrosion and materials and their long term Integrity Management contract with BP. We were confident that FORCE Technology possessed the necessary skills and experience to verify the suitability of the pipeline for the new service”, says Alf Inge Lyse, BP Piping and Structural Engineer.
