Protecting Your Assets Against Corrosion and Environmental Attack
a report by HW Lee and R Miles ULO Systems LLC,(HFZ), Sharjah
This article presents some of the options that may be implemented in order to keep the assets of oil operators fully functional and in a safe working order to maintain production and to ensure revenue figures achieve maximum potential.
This article title is an attempt to persuade risk management of oil operators to consider the options that can be and should be executed to keep the major assets of oil operators in maximum working order.
We all know that oil majors employ risk management departments, but this has been a bit of a black art where the risk management of inoperative assets were not really considered but the failure of a vessel on a project was a major priority.
There is a misappropriation of terminology that means that effort is not going into the correct area where maintenance and repair has become a minor effort until the revenue stops. This is a totally incorrect bias. The sooner accountants looking for revenue realise that, if you have an asset you must look after it, the better.
The number of ageing platforms and pipelines increases annually and globally, and a substantial number are facing operation beyond their intended design life. Therefore, structural integrity and risk management is an increasingly important element of the offshore operator.
Asset management programmes must perform an annual assessment of their structures and facilities and should any significant change to the structural integrity be determined then implementation of an appropriate repair or strengthening plan must be implemented, and sooner rather than later.
Ninety per cent of all offshore revenue utilises the requirement of offshore structures, and any operator who believes that the asset is failure free is adopting that well-known ostrich approach of burying ones head in the sand and hoping that it will not happen to this company.
ULO Systems LLC (formally COLOS) have been actively involved in structural repair projects since 1983. Initial works related to schemes that were implemented as a direct result of collision, impact, storms and fatigue. Recently computer modelling and re-analysis has been used to identify the need for additional strengthening.
© TOUCH BRIEFINGS 2010
As a result of ULO Systems LLC’s extensive experience, a range of specialist services and best practice methods exist that enable the operator to restore the structural integrity and extend the operating life of an asset. To complement these works, ULO Systems have developed a range of specialised high performance grouts, densified cements, epoxy motors and lightweight sodium-silicate-based grouts that may be used to meet the often demanding requirements.
A broad range of services in repair and strengthening are available that encompass specialist consultancy, design, project management, experienced engineers for supervision, together with specialist grouting services, personnel, materials and equipment.
Strengthening Techniques
The most common industry adopted method is welded and grouted repairs however, while a welded repair may typically restore a structure to its initial condition, if the cause of the damage was fatigue loading and this has not been eliminated, then the damage is likely to reappear.
Grouted repairs are therefore widely used to provide additional strength and typical applications include:
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• •
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filling members to prevent propagation of a dent or buckle or to enhance the capacity;
sleeved repairs, filling annulus between sleeve and member to strengthen a thin walled can or to bridge over local damage; leg strengthening, e.g. filling main pile annuli for increased stiffness.
clamped repairs for load transfer from existing structure into strengthening steelwork, at joints, or as part of sleeves to structural members;
leak sealing and plugging of redundant pipework using hot-tap techniques; and
• reinstatement of damaged concrete, wellhead strengthening and underbase grouting of gravity base structures for void filling.
Technical Approach
While the repair design will evolve to meet the parameters of the project, it is often important to design a solution that has minimum weight, or which occupies minimum space on the structure. In these cases, a design that offers the maximum structural efficiency should be adopted.
There is considerable advantage in designing repairs that require minimal in-service inspection and maintenance. The optimum
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Subsea & Pipelines
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