OFFSHORE PRODUCTION HEADER PIPEWORK VIBRATION
Operating Deflection Shape (ODS) survey and structural solution. Working to investigate and reduce vibration and the potential for fatigue failure on mainline production header pipework.
| CLIENT: | Oil & Gas Producer |
| LOCATION: | North Sea |
| INDUSTRY: | Oil & Gas |
| PROCESS: | Oil & Gas Production |
| EQUIPMENT: | Production header |
| PRODUCTS: | Easy-Brace® Machine Sentry® Mobile GERB Visco-Elastic Dampers |
| SERVICES: | ME Scope Operating Deflection Shape (ODS) Pipe Vibration (PV) Survey |
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The Challenge
The client observed high vibration on their production header pipework and required AVT Reliability® to complete an investigation to quantify the vibration and identify inadequacies in the support system. A failure on this line would result in significant safety, production and cost implications.
Our Approach
ODS analysis can be used to provide visual animations of individual mode shapes. AVT Reliability® conducted an ODS survey to understand the complex mode shapes of the production header line and to identify where remedial support should be focused. AVT Reliability® also recorded vibration using the Machine Sentry® Mobile system and assessed vibration data following the Energy Institute (EI) publication: ‘Guidelines for the avoidance of vibration induced fatigue failure in process pipework, 2nd edition.
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Our Findings
The vibration measured exceeded the EI ‘concern’ level at numerous locations and it was clear from the ODS animations that the support of the production header line was ineffective. AVT Reliability® provided a detailed report with accompanying ODS animation videos. The vibration was found to be variable and influenced by transient slugging events.
Our Solution
AVT Reliability® recommended various improvements including the stiffening of existing supports and installation of visco-elastic dampers. AVT Reliability® also recommended installing Easy-Brace® at vulnerable Small Bore Connections (SBCs). AVT Reliability® was not involved in the specification of the damper solution, however, subsequent vibration measurements and a repeat ODS survey showed a significant reduction in vibration resulting in the majority of locations being within the EI ‘Acceptable’ region. The Easy-Brace® solutions installed were also shown to be effective at reducing vibration to the EI ’Acceptable’ region
Follow Up
Following the repeat survey, AVT Reliability® provided the customer with a report, detailing the reduction in vibration levels and providing repeat ODS animation videos. The dampers that had been installed were found to have been undersized for the size and mass of the pipework. AVT Reliability® recommended that these be upgraded to ensure that vibration stays within the EI ‘Acceptable’ region under all possible process conditions.
