Papers

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 Paper presented at the SPE International Oilfield Corrosion Conference and Exhibition,  June 2021. 

Authors -  Watt, Clare; Paterson, Steve; White, Calum; Wilk, Thomas-Peter

Abstract

Corrosion Under Insulation (CUI) continues to be an issue in many oil, gas and petrochemical installations. This paper builds on previous work to examine why the industry has struggled to come up with reliable and cost-effective solutions to the CUI problem. The limitations of different multidiscipline innovations are discussed together with positive examples of the latest promising industry projects and research, including risk management guidance, improved coatings, insulation system materials and design, non-destructive screening techniques and permanently embedded monitors. Key learnings from this review demonstrate the importance of better use of industry plant data to achieve improvements in managing CUI in all innovation disciplines.

Paper intended for MECOC 2020 - Cancelled due to COVID-19

Author - White, Calum

Abstract

Corrosion Under Insulation (CUI) is an ongoing scourge of the oil and gas industry, with costs spiralling due to increasing occurrences of the failure mechanism on ageing assets. It is estimated that corrosion costs the global economy up to $2.5 trillion annually (approx. 3% of global GDP), with 45% of this related to the oil and gas industry (NACE IMPACT, 2016). These costs are without considering indirect expenses associated with sudden or prolonged shutdowns. Even though guidance, standards and technologies exist to help combat CUI, it is still a large proportion of any maintenance budget. Even with large spending, failures occur, with potentially devastating consequences.

CUI occurrence is largely governed by climatic conditions, process temperatures and insulation system effectiveness at minimising the time of wetness of the steel substrate. The removal of insulation followed by visual inspection is the most reliable method of detecting CUI and maintaining integrity. However, this is not always possible or desirable, either due to budgetary, time or process constraints. Incorporating screening technologies within inspection cycles can aid in overcoming these restrictions, revealing if CUI is present, remaining wall thickness has reduced, or if conditions that allow CUI to develop are occurring, such as moisture presence within the insulation systems. These technologies are referred to as non-intrusive inspection techniques (NII) due to being able to leave the insulation system undisturbed. This means that no removal of the insulation system is required to implement them.

The most promising NII technologies regarding CUI screening are based on:

• Real-time radiography (RTR) – Outside pipe diameter profiling

• Pulsed eddy current (PEC) – Remaining wall thickness area averaging

• Long range ultrasonics/ Guided wave ultrasonics (LRUT/GWUT) – Sound reflection due to CUI cavity

• Backscatter techniques – Moisture detection within insulation systems with neutrons or x-rays

• Thermography – Moisture presence detection by insulation system performance degradation after excessive exposure to water (e.g. rain, deluge systems, etc.)

Some of the above technologies have a higher maturity and deployment history than others. Applicability of methods can vary according to the different requirements of industrial sites (remote locations, power supply restrictions, insulation materials, etc) and compatibility with advanced access methods (MEWPS, rope access, etc). This paper will discuss these technologies, including their advantages and disadvantages, best areas for deployment and expected results. It is important that as an industry we continue research and development into these NII techniques, as well as incorporating more effective RBI schemes and insulation practices so that we can work towards a future free from unpredictable CUI failures.

Paper presented at European Confederation of Corrosion (EFC) meeting, May 3 2018

Authors - White, Calum

Abstract

Corrosion Under Insulation (CUI) is an ongoing scourge of the oil and gas industry, with costs spiralling due to increasing occurrences of the failure mechanism on ageing assets. It is estimated that corrosion costs the global economy up to $2.5 trillion annually (approx. 3% of global GDP), with 45% of this related to the oil and gas industry (NACE IMPACT, 2016). 40-60% of pipe maintenance costs are associated with CUI and approximately 10% of maintenance budgets are spent on repairing damage caused by CUI alone. This paper focuses on and discusses the application of two of the newer technologies in NDT with an aim of screening for CUI: Real Time Radiography (RTR) and Pulsed Eddy Current. These technologies can be combined with other site services to provide a holistic support package (one-stop shop).