The Aberdeen Branch has several significant Events scheduled for later in the Summer and would particularly like to draw your attention to its Annual Corrosion Forum (ACF) scheduled fo 24th August. This year event is arranged to be held in TRAC Oil and Gas premises close to Aberdeen Airport.
This will be the first ICorr event in more than a year that we are going to conduct in person. The theme for the ACF this year is External Corrosion Management. The programme consists of 8 presentations to be presented by speakers from various companies, all very active in the integrity management field. Practical demonstrations in the TRAC workshops will follow in the afternoon.
Those interested in joining this Event should register your interest with ICorr HQ using the attached Form.
This event is going to be conducted in an outdoor area with Catering Marquee (with restricted access into the main building) in order to be able to accommodate the speakers and the attendees with proper social distancing#. #The current COVID precautions mentioned in the attached agenda, may be varied due to easing or tightening of government recommendations or TRAC instructions.
During March, the branch welcomed Dr George Sergi R&D Technical Director at Vector Corrosion Technologies, which, provides corrosion mitigation techniques for the civil engineering and construction industries. He is the author of several international patents for corrosion protection of steel reinforcement and these were discussed in a talk entitled “Galvanic Corrosion / CP Control of Reinforced Concrete; Lessons learnt from 20 years of Site Trials”.
Sacrificial anodes have been used in reinforced concrete structures for up to 20 years. These prototype anodes, designed for a 10-year life, have continued to deliver a reduced but significant current, complying with presently accepted CP criteria. However, there are still issues with patch repair of concrete with the condition of the re-bars not being fully understood, and corrosion re-occurring at the periphery of the repairs termed ‘ring effects’. Studying long term installed conventional sacrificial anodes and identifying the issues, has led to the development of a new Fusion™Anode, which seems to solve the issue of recurring corrosion at repairs.
In order to prevent the initiation of corrosion in a chloride contaminated environment, the current density needs to be 0.4 to 2 mA/m2, much lower than the amount necessary to stop on-going corrosion activity which is 2 – 20 mA/m2.The zinc anodes used for this new technology are encased in a high porosity mortar (to accommodate migration of corrosion products), and also saturated with lithium hydroxide.
Site trials on a bridge in Leicester 20 years ago involved the removal of concrete to reveal the re-bar area, and attachment of anode discs at the peripheral areas of the patch, but, rather than wiring to the rebar, the anodes were wired back to a junction box wired to the steel reinforcement, which meant the anodes could be turned off and on, current could be measured, and the polarisation could be monitored. The zinc consumption could also be monitored and calculated from the Faraday Equation.
Monitoring showed that the cumulative charge from the anodes is linear w.r.t. time for first 5 years then the charge started to fall, perhaps due to the saturation of the Li hydroxide mortar. Tests showed that by disconnecting the anode for 24 hrs then reconnecting, the mean ‘instant on’ current could be established for the anodes within 5secs of reconnection. This represents the power which remains within the anodes – which was 1-1.5mA. After 14 days the current dropped to 0.5mA; this coincided with LiOH saturation witnessed in the sections.
Looking at the current density (CD) over the 20 years and plotting on a log scale it was seen that the decline of CD was actually exponential. From this study, an ‘ageing factor’ could be determined as to how quickly the protective current halved; this was ~7 years, it then halved again after 14. The study of many other sites enabled ageing factors from sites to be compared, and by reducing the anode spacing by ~1/2 the ageing factor achieved could almost be doubled.It was concluded that the service life of existing standard galvanic anodes used in concrete repair is expected to be between 15 years and 30 years.
As a result of these long-term studies of standard galvanic disc anodes, the New Fusion™ Technology was further developed to have an anode with two stage protection using a battery which first delivers impressed current to arrest corrosion and passivate the steel and then a galvanic anode using a small ’cathodic prevention’ current to maintain the passive state for the remaining life expectancy.This product is an ICCP element and galvanic element with electronics, encased in a stainless steel can and surrounded by alkaline mortar. In laboratory tests, the installed anodes were switched on and off in the ICCP stage to check the polarisation level and the effect of wetting the slab, seen as an increase in the current density. Similar confirmations can be obtained during the galvanic protection phase. Site tests were also conducted to optimise and monitor the spacing, current levels and configuration of the anodes.
From the development work it was established that the key factors were:
An initial charge at the top end of CP current densities that can arrest corrosion of steel.
The level of applied charge to achieve corrosion arrest depends on the corrosivity of the concrete environment and the level of applied current density.
Confirmation that passivation of steel can be maintained long-term with galvanic anodes.
During polarisation of re-bar in concrete it was witnessed that the chloride ions started to move away from the steel and hydroxyl ions are produced at the steel. This led to a reduced Cl_/ OH_ ratio and a reduced corrosion risk with high alkaline levels at the steel interface and low chloride, increasing with distance from the steel. It was also determined that with higher current densities such as can be produced by impressed current technology, highly alkaline areas, above that of base concrete alkaline levels, can be created at the steel which contributes to reversing the corrosion process. Lab tests using between 1% and 3% chloride showed that it took longer to passivate the steel the more residual chloride in the mix at a current density = 30mA / m2 to the steel reinforcement. By extending the experiments, the charge required to passivate the steel and arrest corrosion at various chloride levels was established.
In summary, George highlighted the benefits from higher levels of current possible by ICCP in the initial years of installation in order to passivate the steel and create more favourable alkaline conditions at the reinforcement for forward protection by GACP.
Again, due to COVID restrictions, the annual joint conference with the Marine Corrosion Forum (MCF) was reformatted as a lunchtime webinar week, held with great success between 26-30 April 2021. Attendances averaged 77 per day and exceeded all expectations, which suggests that the way forward will most definitely be that of blended learning, possibly with live streaming of ‘face to face’ events to our international audience (ICorr itself having nearly 600 overseas members}.
Day 1 featured, Ray Sivarajan, Senior Integrity Engineer and Bill Hedges. Corrosion & Integrity Management Consultant for ICR – OMNI, presenting their “Novel integrity operating system” which uses machine learning to give integrity engineers a continuous and holistic understanding of their business assets in real time. Organisations today face increasing challenges in the changing geopolitical and industry dynamics, which can have huge impacts on the overall success of the business. Constraints such as resource and experience shortages make it ever more difficult for organisations to achieve the efficiency levels required to maintain profitability, whilst maintaining safety and environmental levels. The software boasts built-in automation between modules, workflow tracking and notifications – a first of its kind for integrity software solutions taking visibility and control of integrity activities to a new level. Each module can be used alone to integrate with existing integrity systems, or seamlessly used together as a complete solution – to support organisations in their efforts of digitising their full integrity lifecycle. Further information is available at, https://icr-world.com/omni
Day 2 saw Michael Smith, Senior Engineer Data Scientist with ROSEN UK discuss “Virtual in-line inspection for corrosion management in un-piggable pipelines”. Over the past 30 years, vast amounts of ILI data have been collected all around the world. Although pipelines are diverse in their characteristics, many share similar risk profiles for common pipeline threats such as external and internal corrosion. This has led the industry naturally towards machine learning as a complementary corrosion monitoring solution for pipelines that cannot be inspected using ILI. The results of a “Virtual ILI” create clear justification for planning actual inspections or maintenance in challenging pipelines and for a given uninspected pipeline, it is possible to now source data for similar inspected pipelines and use machine learning algorithms to generate predictive models.
Day 3 profiled Ross Hubble, Applications Engineer with COMSOL, who gave a very modern insight into “Modelling Corrosion and Corrosion Protection”, and discussed some of the benefits of corrosion modelling and what kind of simulations can be performed, starting out with a brief introduction to corrosion simulations and how the theory can be applied to a simulation in the proprietary Multiphysics® software. After the introduction, several modelling examples within the corrosion and corrosion protection field were presented. Modelling allows engineers and scientists to investigate these processes and gain a better understanding of the extent to which corrosion could occur over the lifetime of a structure, and implement preventative measures to inhibit this.
Day 4 had Hamed Habibi, Lead Engineer with Spier Hunter, deliver a most interesting presentation on “Developments in remote magnetic monitoring of carbon steel pipelines to locate and measure abnormal stress”, highlighting recent developments in an emerging non-intrusive sensing technique developed to detect localised abnormal pipe wall stress, such as corrosion and metallurgical defects by mapping variations in the earth’s magnetic field around pipelines. This presentation explored how measurements of remote magnetic field can be applied to define the location of defects in operational pipelines, quantify the associated abnormal stress, report the position of girth welds and to concurrently report a 3-dimensional map of the pipeline route.
Day 5 concluded with Daniel Sandana, Principal Engineer of ROSEN UK, presenting “Addressing the risk of Hydrogen-Induced Stress Cracking on Pipelines”.The role that hydrogen could play in the transition to low-carbon economy has refuelled the emphasis on hydrogen-related cracking mechanisms, and how these could affect the integrity of the energy infrastructure. Hydrogen-cracking mechanisms can nonetheless occur on our existing pipelines, when the effect of CP or H2S is considered. Such mechanisms will actually occur at a greater scale than what would be considered when looking at the sole effect of gaseous hydrogen. The purpose here was to get a better understanding of the problem of HISC due to CP on materials, used onshore and subsea, and how to address it.
Dr Yunnan Gao (Aberdeen’s Digital Strategy and Communications Officer) kindly compiled an all-encompassing Playlist called “ICorr / MCF Webinar Videos in April 2021”. This may be found on: https://youtube.com/playlist?list=PL-Hz5BsB9C8JB5fGT6Ubsy-rK0ITrYlU2
Looking ahead, the branch is very pleased to announce the return of its annual corrosion forum on 31 August 2021 at TRAC (The Rope Access Company), an enthusiastic supporter and branch sponsor of Aberdeen for many years.The day will comprise a full range of corrosion awareness talks in the morning and many interesting demos in the afternoon. To register advance interest in this event please contact the ABZ events officer, Amir Attarchi, at email@example.com, giving your full name and company.
Before that, members of the branch will be supporting the SPE virtual oilfield corrosion conference and exhibition, where industry leaders discuss recent innovations, trends, and concerns as well as practical challenges encountered within the oilfield corrosion community.See http://go.spe.org/lic6268, and for which registrations are now open at: https://www.spe.org/events/en/2021/conference/21ofcs/register.html
Finally, and certainly not least, we are very pleased to welcome our new branch chair, Hooman Takhtechian, who takes up his new role after several years as a committee member, and to thank Dr Muhammad Ejaz for a very successful 2020-2021 season.
ICorr are jointly promoting with EFC the following Event, as a follow-up to the April EFC Corrosion Awareness Day.
ICorr/EFC/CR are focusing on a new generation of young engineers who will be at the heart of combatting corrosion challenges of the future and playing an active role for a safer and more sustainable world.
The CR CUI Over Coffee session on Friday 21 May at 11:00 GMT will explore the Life of a Young Corrosion Engineer with guest speakers: Marta Mohedano Sanchez, President of the Young EFC – European Federation of Corrosion Board and Bill Hedges, President INSTITUTE OF CORROSION and former Chief Engineer at BP.
CorrosionRADAR’s Young Corrosion Engineer Claudia Martínez Piñón, (a recent Graduate of the ICorr Young Engineer programme) plus CR CEO Dr. Chiraz Ennaceur will talk about the day-to-day realities of dealing with corrosion, what it is like for young people joining our community, their life and opportunities.
The panel will also consider the changing landscape for corrosion management.
This session is ideal for those who would like to learn more – young engineers, academics, entrepreneurs and leading operator experienced professionals driving change.
The SPE Virtual International Oilfield Corrosion Conference and Exhibition, taking place across 16–17 June 2021, will bring together international scientists, researchers and academics to explore the latest challenges facing the oilfield corrosion community including investigative work and front line experience. Attend >
Discover the future of oilfield corrosion at the SPE Virtual Oilfield Corrosion Conference and Exhibition.
Hear industry leaders discuss recent innovations, trends, and concerns as well as practical challenges encountered within the oilfield corrosion community.
Help shape opinion on industry changes, developments, and innovations on Oilfield corrosion at the Virtual SPE International Oilfield Corrosion Conference and Exhibition 2021.
Following on from the very successful lunchtime webinar series covering Pipeline Coatings, Linings and Cathodic Protection Safety Considerations, with MCF, the branch held its annual joint technical meeting with the Energy Institute (EI) on 26 January 2021 on the theme of, Corrosion Under Insulation – why are we still talking about this? There were three excellent speakers for this Event – Rebecca Allison (OGTC– Oil and Gas Technology Centre), Yvonne Onuegbu (EI AHI – Energy Institute Aberdeen Highlands and Islands) and Jim McNab (OIS – Oceaneering International Services).
Rebecca Allison, Head of Emissions Reduction at OGTC.
Rebecca Allison discussed the results from a recent survey by Corrosion Radar which showed that over 95% of the O&G Industry felt that management of Corrosion under insulation (CUI) was not currently adequate, and should be up-dated or radically transformed. She noted some industry facts identified in the survey:
CUI incurs 40 – 60% of the process plant maintenance costs within the UK Continental Shelf (UKCS), and costs the UK £28 billion every year |rising to an estimated £4 trillion globally.
CUI is one of the major causes of accidents in the oil and gas industry, since 1984, out of 137 major oil and gas accidents reported within the EU, over 20% have been associated with CUI.
Corrosion under Insulation, an ongoing Issue.
The key components of a CUI strategy are Prediction, Monitoring and Detection:
Prediction using data & digital analytics for continuous monitoring to identify where it will occur.
Monitoring using sensors to detect moisture and early signs of corrosion using retrofitted and cost-effective instrumentation on Late Life and Brownfield Sites.
Detection deploying automated and efficient inspection techniques, although there is a need to push for more investment in new technologies. A goal was set 4 years ago by OGTC to eliminate all CUI failures in Oil and Gas fields by 2026 but so far it cannot be said that any significant progress toward this goal has been made. OGTC welcomed the resurrection of the industries CUI Forum with Henrik Andersen, Materials, Corrosion & Inspection Lead at Shell UK Limited as its chair, and which hopefully as an industry, new ways of working and use of Management of Change (MOC) to push through new technologies can be found.
Yvonne Onuegbu (Energy Institute Aberdeen Highlands and Islands).
Yvonne Onuegbu briefly explained CUI as the external corrosion of pipework and vessels that occurs beneath insulation following ingress of water and corrosive contaminants. There are several Industry guidelines and recommended practices which have been developed, the most prominent being: API RP 583 – CUI and Fireproofing, NACE SP0198 -2017, EFC WP13 WP15, and EI Guidelines for Design, installation and management of Thermal Insulations systems.
CUI presents so many challenges due to the many factors and parameters involved namely, temperature, moisture and contaminants, plus inspection techniques, maintenance requirements and cost. For temperature alone, carbon steel suffers issues from -4C to 175C (mainly in the range, 30 -120C) and for CRA materials between 20C and 200°C, commonly manifesting in the form of chloride stress corrosion racking and/or localised chloride pitting (unless well coated). The moisture or water can be from rainfall, steam discharge, condensation or sweating. Contaminants increase the corrosiveness of the water which comes mainly from the surrounding atmospheric / marine environment, and are often trapped within the insulation materials themselves.
About 20% of pipework failure and maintenance costs since 1994 are due to CUI, so there is good justification to pursue solutions. When trying to investigate CUI the external condition of the cladding can indicate obvious issues if it is disturbed or broken but often intact insulation has to be removed to investigate and reveal corrosion beneath the covering, which has been indicated by other detection techniques, leaks or alarms. Non-intrusive methods of inspection (NII) such as Radiography (RAD), Long Range Ultrasonic Testing (LRUT), Pulsed Eddy Current (PEC) and Guided Wave UT, may be used but they all have their limitations, detection capability, varying speed and cost, with sometimes inconsistent results and individual interpretation issues. RAD in particular can be a slow and hazardous operation requiring scaffolding and containment of the test areas. LRUT is more of a screening tool to indicate general areas where insulation should be stripped off, and (PEC) will detect gross defects but is not so good on minor defects.
Yvonne summarised that for effective management of CUI, the process can be broken down into a structured approach of, investigation, analysis, assessment and mitigation. The assessment process must prioritise the areas considering critical and historical data to focus programmes of work according to the probability of failure followed by Insulation removal, either full or partial.
The CUI Mitigation Strategy involves defining the inspection scope, evaluation technique, and periodicity of inspection and coverage. This stepped approach summarises current industry thinking.
Jim McNab, (Oceaneering International Services).
Jim McNab then described Focused Stress Concentration Tomography (FSCT) which is a specialised inspection technique for insulated pipelines and being developed by Spier Hunter Ltd in association with Oceaneering with funding from OGTC. The new technology stems from an existing SCT technology whereby an operator wears the inspection tool and walks over the known line of buried pipeline while in operation. It is magnetometer based and it ‘absorbs’ or listens to the magnetic field changes around localised flaws and interprets them as Stress Concentration Zones (SCZ’s). Off-line analysis of the collected data shows SCZ location, severity, pipeline route and depth of burial. FSCT is a ‘blinkered’ version of traditional SCT technology designed to focus the magnetometers and shield them from external magnetic influences. The objectives of this technology are quick screening and real time data interpretation.
A case study showed the evaluation of an un-piggable pipeline which had identified localised high stress concentration zones. DCVG coating inspection also indicated local coating defects. The corrosion under the coating was revealed to have spread some 10m along the pipe past the defect. The FSCT Probe can be mounted on a pipe using a bracelet frame or used as a hand-held unit which is guided over a marked grid by the operator in axial or circumferential directions on pipes in any orientation. This has so far been tested on 4” to 20” diameter samples along with a 5m diameter pressure vessel, and on insulation thickness up to 65mm.
FSCT Probe in use on thermally insulated gas piping.
The newly developed probe is ruggedised to IP65 and has been tested in operational O&G environments at Flotta Terminal in Orkney and St Fergus Gas Plant installation near Peterhead, but still requires extended data gathering analysis in order to develop algorithms based on real CUI examples, refine the technique, and gain assurance. Future objectives are therefore to determine the limitations of the technology, in terms of maximum insulation thickness, possible stand-off of the probes, and determining how different insulation materials or jacket types influence the results.
Rob Hardy – Commercial Manager, Tracerco.
On Tuesday 23rd February 2021, Rob Hardy of Tracerco gave an informative presentation to the Branch illustrating a successful cross-over of medical technologies to the Oil and Gas Sector. Robert holds a master’s degree in chemistry from the University of Newcastle upon Tyne, and has more than 10 years’ experience managing commercial operations in the non-destructive testing market, with knowledge of computer tomography and nuclear magnetic resonance techniques. Robert joined Tracerco in 2019 to focus on the development of the Discovery™ Subsea CT scanning service in Europe, Middle East, Africa and Australia.
Tracerco’s inspection services are now used globally subsea to provide operator with assurance of the integrity of their assets and to diagnose flow abnormalities. Tracerco have developed the DiscoveryTM unit, which is a diagnostics instrument for pipelines designed to detect wall loss, corrosion, and build-up such as hydrate, sand, asphaltene, scale or wax. It can be deployed on live piggable and un-piggable pipelines, without any interruption to production, or the need for pipeline modifications. Unlike alternative technologies such as ultrasonic and pulsed eddy current methods, that first require expensive subsea concrete coating removal, this method provides a high-resolution image of pipeline contents and pipe wall thickness, enabling pipeline integrity flaws and flow assurance conditions to be accurately visualised.
The unit is deployed using a Remotely Operated Vehicle (ROV) and clamped around the pipe. Real-time communications allow instant assessment of pipeline conditions and different versions are available based on pipe diameter and depth of deployment. The Computerised Tomography (CT) technique used by the Discovery unit is analogous to the medical scanning used in hospitals with a few adaptations to take it subsea. When the CT beam passes through a material the beam is weakened according to its density, which is known as the attenuation co-efficient of the material. Multiple line of site measurements across the items to be scanned build up a picture known as a ‘Tomogram’ which is created by computer reconstruction models. Information about the pipeline wall thickness and integrity is collected in one scan, and complete picture of the pipeline can be fed into integrity pipeline management systems for inspection.
The technology is truly non-intrusive, and with pre-project calibration, it can scan through any coating, such as concrete or polymer, with no coating damage or interference with production. This can be performed at water depths up to 10,000 feet and is capable of scanning 6” to 26.5” pipe ODs using a work class ROV. Features in the Tomograms can be identified by comparing with libraries of known defects, but for extraordinary project challenges, calibrations can be carried out on representative samples. Rob discussed the principles of collection of integrity / corrosion data subsea and various NDT principles deployed with the Discovery CT Scanner.
In order to assess pipeline integrity and ensure efficient production of assets over time, oilfield professionals are sometimes faced with having to perform pipeline inspection where pigging is not an option or deemed too risky. Previously inspecting a pipeline from the outside was a very costly and often an ineffective high-risk operation. This tool allows online inspection of the pipe from the outside without removing the protective weight coating.
Several case studies were presented to demonstrate how accurate the technique is at identifying aspects of pipe structure integrity and geometry, and wall thickness mapping was shown through concrete weight coatings. Ordinarily the vast majority of concrete pipe seabed inspections require direct contact with the pipeline metal after removal of concrete.
CT Scanning facilitates sections being taken through piggybacked lines and pipe bundles, accurately mapping their internal positioning and misalignments. The technique is ideal for these types of diagnosis as normally the inner pipe cannot be inspected without diss-assembly and the annulus area can be seen in detail. It can expose internal pipes which may have buckled and moved to the wall of the outer pipe and pick up rust formation inside the bottom of the pipe casing.
The technique easily creates images of internal and external dis-bonded coatings and can also be used to identify corrosion under insulation without the need for removal or destructive testing. Internal and external corrosion is readily identified along with pipe wall thinning, positions of weldments and any wall thickness losses through erosion. The technique can also identify thermal expansion effects and even fatigue, as internal pipes can move out to the wall of the carrier pipe maybe through damage to centralisers. Images which are blurred during the scan reveal vibration of the inner pipes during flow.
(Left) Asphaltene @ 1.2g/cc and Gas Pockets. (Right) Scale @ 2.3g/cc. CT scans of internal flow constraints.
One of the main uses for the technology is in flow assurance and characterisation and location of blockages. About 50-80% of remediation attempts usually fail first time due to lack of information and wrong strategy to clear the product. The scans can characterise the densities of the blockages and therefore determine if the build-ups are asphaltene, sand, scale hydrate or wax. Conversely, identifying the absence of blockages allows operators to modify their inhibition strategy thus reducing the expensive disposal of an environmentally unfriendly product with huge cost savings. Developments in the market for the instrument are in ‘Fast Screening’ with real time data to find points of interest. Full duration scans can then be applied or automatically triggered wherever an anomaly is identified to detail and diagnose the features.
The latest information about branch events can be found on the diary page of this magazine and at: https://www.icorr.org/events/category/aberdeen-branch/list/
All Aberdeen events (both presentations and associated Q&A) are recorded and may be found at: https://www.linkedin.com/in/aberdeen-icorr/