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ABSTRACT Corrosion and erosion on subsea installations is a big challenge for oil and gas operators and can carry significant cost and risk. Better monitoring of seabed installations will lower maintenance costs, provide greater control and reduce risk to installation integrity.
For topside installations, there are several methods of inspection and monitoring available, but subsea, the challenge has been to find technology that works and provides real value. The growing number of aging subsea installations increases the need for good retrofit solutions.
Research and development of guided-wave methods for asset monitoring and screening has been ongoing for several years and over this time ClampOn has developed a non-invasive instrument which can be used on new subsea installations or retrofitted by ROV to existing installations.
While developing this guided wave based system, ClampOn's research team has worked in parallel to develop and implement more technology in the system which will provide high-resolution 3D data for the area being monitored.
Tomography is already used elsewhere, such as in medical applications, but has never before been used as part of a fixed subsea system to monitor wall thickness loss in pipelines.
Key learning outcome:
ClampOn has developed a system that not only provides direct measurement of and important information about ongoing corrosion and erosion, but also offers highly accurate high-resolution 3D imaging of subsea pipes securing pipeline integrity.
1. INTRODUCTION Structural health monitoring of subsea production templates, flow jumpers, manifolds, and flow lines relies on two main approaches; pre-installed monitoring sensors and inspection by remote operated vehicles (ROV). Inspection by scraper tools can be performed at some locations, while other sections may be inspected using cable-operated tools. Such inspection is however expensive and may require production shutdown. For the purpose of topside corrosion and erosion monitoring, there are many technologies available but subsea, the challenge has been to find technology that works and provides real value. The subsea environment is difficult to access for instrument maintenance and verification of monitoring data, and many pre-installed systems for monitoring wall thickness have proven to be of little use. ROV-operated wall thickness sensors most often provide indicative readings only, and are costly to operate. A major challenge is that "hot-spots", i.e., areas particularly susceptible to erosion and corrosion, are often detected only after the asset (pipe lines/templates etc.) has been in operation for a while. Accordingly, the ability to retrofit a wall thickness monitor on identified hot spots subsea can be of great value on many locations.
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