High resolution thickness mapping is a widely accepted method for fitness for service inspection and provides a permanent and quantitative record for remaining life assessment and through periodic campaigns can be used for comparative analysis.

Subsea infrastructure introduces many challenges for inspection delivery and although robotic systems have been readily accepted, traditional methods of ultrasonic thickness reading is not possible through a large range of subsea coatings.

In 2017, a major Oil Company started a collaboration with a subsea inspection service specialist to investigate the plausibility of Acoustic Resonance Technology (ART) on its insulated pipeline inventory. Having recognized the potential impact this technology could have in the subsea integrity process, the company supported the commercialization of this technology with the subsea service provider in 2020 and since then the method has continued to evolve.

Nowadays in 2023, acoustic resonance technology is becoming rapidly recognized for the first-choice method for insulated and coated piping for subsea infrastructure. It provides fully quantitative information, is radiation free and can collect large areas of data points extremely quickly.

The paper will explain the timeline of technology evolution from initial concept, lab tests and successful field trials. It will describe the method that was applied, how the signal processing and software algorithms determine resonance as a wall thickness and provide practical examples of the benefits of this method. It will talk about the different coatings that are typical for subsea applications and describe how the new acoustic resonance technology can eliminate the requirement to remove this coating or deploy a less productive and sometimes challenging radiographic method.

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