Abstract Post commissioning of the new AGDAS gas treatment facility (Offshore Associated Gas (OAG)), several failures in 316L stainless steel piping and equipment occurred. Since OAG commissioning in November 2010 till October 2011, 13 failures were recorded. All failure investigatios concluded that the immediate cause of failure was internal Chlorides Stress Corrosion Cracking (ClSCC). ADGAS considred actions to ensure the safe and efficient operation of OAG. To quantify the inherent risk associated with the operation of OAG assets under the likelihood of failure due to ClSCC, a Risk Based Assessment (RBA) exercise was conducted by an ADGAS multi-disciplinary team.
Results of this assessment were used for as the basis for determining the risk associated with each and every stainless steel asset, prioritise the replacement works and plan for inspection and monitoring. In otherwords, provide the basis to evaluate the extent of the problem and hence put a mitigation plan. A tool for risk (RBA) evaluation of ClSCC was developed in house.
This key activity paved the road towards setting an overall action plan to contain the OAG risk of ClSCC. The action plan has managed to prevent further leaks in OAG. Action plan included the launch of special advanced nondestructive testing program capable of detecting premature stress cracks in stainless steel, temporary composite wrap repairs at specific high risk locations, a dedicated emergency and HSE program in addition to other actions. Chlorides stress cracking leaks could have resulted in major consequences in terms of HSE, loss of production and disruption in gas supply.