The Devil Is In The Details - Lessons Learned From Design Failures in Underwater Monitoring Systems

摘要

Success is of course the most desirable result of any project, but the value of failures in terms of advancingtechnology should not be underestimated. This paper draws on the experiences of over thirty years ofdesigning and delivering operational monitoring systems for the oil and gas industry, condensed to a shortpresentation of valuable lessons learned from less-than- successful designs and deployments.The article covers several principle themes, presenting the failures experienced, evaluation of the rootcause of the failure, and subsequently the measures implemented to mitigate similar failures in the future.The insights and solutions presented will be beneficial for organizations planning or executing the designand installation of an underwater monitoring network.The first theme presented is failure due to corrosion. Corrosion is an insidious process, which if notproperly managed in the system design will ultimately result in failure. The obvious culprit is the use ofcommon steel, whereas less obvious culprits include combinations of metal types (including titanium),inadvertent use of alloys, surface treatments and coatings, as well contact with sediments, cements andgrouts.The second theme is barrier philosophy - leaky enclosures, hygroscopic materials, and capillary forcescan all contribute to failures. A leaking barrier does not necessarily mean a catastrophic failure, and withthe implementation of a few good design details, even a leaky system may be able to operate for longperiods before eventually failing.The third theme examines lessons learned related to deployment and operation of equipment in variousenvironments: in conjunction with permanent infrastructure, as autonomous installations on the seabed, oras moored or drifting floating structures. Each of these operating environments poses challenges,including harsh natural environmental conditions, accessibility, interaction by third parties, and variousrules, regulations and company specific practices.Sound engineering combined with practical experience is the best starting point for a successful design.This article summarizes some of our ’trial and error’ experience related to the practical and operationalchallenges inherent in an underwater monitoring system design and deployment, and these experienceswill be useful for others when commissioning, designing and deploying similar systems.