Underwater inspection of offshore oil and gas structures in the North Sea has evolved over the last 20 years The initial techniques were fairly primitive by comparison with current methods
This paper examines the development of underwater inspection in the North Sea from the late 1960's to the present day and considers how programmes can be rationalised It looks at both techniques used and training given Current inspection methods are reviewed with particular emphasis on steel structures
There is generally greater opportunity to optimise inspection costs on steel structures, be they floating or fixed Concrete gravity platforms are discussed but by their very nature the inspection requirements for concrete are less onerous The key to optimisation of underwater inspection programmes begins at the conceptual or design phase of a new platform Input by qualified engineers can significantly reduce inspection and maintenance costs downstream
Substantial financial savings can also be made by reviewing and rationalising inspection programmes during the service life of offshore structures Quest Consulting Ltd has extensive experience in this area and its staff have worked in this capacity for a number of North Sea Operators over the past ten years.
It is important that with any inspection programme, the reason for inspection is clearly defined This should be to ensure the continuing ‘fitness for purpose’ of the structure by most the cost effective methods To achieve this, the engineer must have sympathy and an understanding for the loads and possible degradation of the structure
This paper concludes with some of the methods available and details the data required to fully optimise an underwater inspection programme
Quest Consulting Limited 1s a professional engineering consultancy based In Aberdeen The optimisation of underwater inspection programmes is an area that we are particularly skilled In. Individually we have been involved In underwater activities since the late 60's though the majority of our work has been conducted over the last ten years
We have been involved in the rationalisation and streamlining of underwater inspection programmes for a number of North Sea clients However, for the purpose of this presentation we will reflect on the following areas -
Brief History of North Sea Inspection
Current Inspection Techniques
Requirement for Inspection
Optimisation by Design
Optimisation during Service Life
Conclusions
For reasons of client confidentiality any examples given will be non-specific
Underwater Inspection has come a long way over the past 20 years In the late 1960's and early 1970's underwater inspection often comprised the deployment of divers using scuba and limited, if any, contact with the surface (There were no ROV'S as we know them today, although manned submersibles were being used) Typically the diver would be briefed prior to diving, take whatever equipment that was necessary to execute the task and then plunge overboard
