DNV GL has now launched a joint industry project (JIP) to develop a methodology to evaluate fractures and cracks using a Single Edge Notched Tensile (SENT) test designed specifically for sour service environments. Eight participants are on board and the JIP is still open for new participants.
A SENT test is designed to simulate loading conditions and crack depths similar to those experienced by pipelines operating under normal conditions. Research conducted in DNV GL’s laboratories shows that in a sour environment, where fluids such as H2S, H2O and CO2 may be present, results can be highly variable depending on numerous environmental and test parameters. Current guidance under DNV-OS-F101 and DNV-RP-F108 does not reflect this.
Dr Jens Petter Tronskar, DNV GL Vice President and CTO of the Deepwater Technology Centre in Singapore, says: “The JIP will involve detailed experiments and analysis to provide a better understanding of the key parameters known to impact fracture toughness test results. This will enable the development of a guideline which may further develop into a Recommended Practice.”
The JIP is a joint effort between DNV GL Singapore Deepwater Technology Centre and DNV GL’s laboratories in Singapore and Columbus and will be run in three phases over two years.