FiGS® is a unique non-contact inspection tool that completely transforms Cathodic Protection surveying for submerged marine structures.
FiGS® is the most advanced cathodic protection survey technology in the market. It equips you with a precise understanding of your assets’ condition faster and with more comprehensive data, enabling well-informed decisions that can lead to significant cost savings in life extension and anode replacement projects.
FiGS® is significantly more sensitive and accurate than any other cathodic protection survey technology available
Utilising state-of-the-art non contact Field Gradient Sensor technology, FiGS® carries out highly accurate measurements with a resolution and detection level that surpasses all other cathodic protection survey methods even when the target is buried.
A FiGS® survey is the fastest way to acquire reliable cathodic protection system data
The FiGS system is the most efficient method available for measuring the status of cathodic protection. It cuts operational time, resulting in lower vessel and ROV costs and associated environmental impact, making it an invaluable tool for both energy companies and offshore engineering contractors.
FiGS® data allows accurate predictions about future condition of your assets
Major Energy Operators all over the world have already adopted FiGS® as their standard tool for Subsea Integrity Management due to the unmatched data quality and survey efficiency, as well as the system’s unique data reliability, which enables precise predictions of the future condition of underwater assets.
Periodic stab measurements are the traditional method for cathodic protection inspection. Unlike a FiGS® survey, which enables data to asses show hard the anodes are working, stabbing comprises local measurements of just the electrochemical potential and accurate readings can only be obtained through direct contact with the anode or on bare metal, if available.
The output is solely information about the current status of a cathodic protection system. A large number of readings combined with cathodic protection modelling are typically required to be able estimate the future cathodic protection status of an asset. Further, costly and time-consuming cleaning of the measurement area is usually necessary in addition ensure a dependable reading.
Using non-contact sensors, no cleaning is required prior to a FiGS® cathodic protection survey, making it much faster to identify issues related to coating degradation and damage. It’s easy to pinpoint anodes that are not working as intended, and cathodic protection current drain to adjacent structures. Critically, with FiGS®, it’s easy to identify these issues whether the pipelines or structures being surveyed are buried or not.
Knowing the exact condition of your cathodic protection system allows for an accurate assessment of remaining service life – this can only be achieved using FiGS®
Operational benefits of using FiGS® to monitor and protect cathodic protection on underwater structures.
Versatile applications of FiGS® in cathodic protection survey
The FiGS® system revolutionizes the way cathodic protection surveys are conducted across various subsea assets. Designed generally for oil and gas and offshore renewable industry users, FiGS® brings unparalleled precision and efficiency to assessing the integrity of pipelines, jackets, and submerged structures, whether exposed or buried.
Ideal for extending the lifespan of almost any critical underwater infrastructure, FiGS® supports detailed cathodic protection modeling, enabling predictive maintenance and strategic retrofitting to safeguard your valuable assets against corrosion.
FiGS® is transforming integrity management across wide-ranging applications, from routine inspections to comprehensive lifetime extension and full-field projects.
FiGS® enhances the service life of offshore structures by providing precise, non-contact cathodic protection assessments through advanced field gradient measurements, thus reducing the operating time required for offshore vessels and ROVs.
In-field structures
Through the ability to identify coating defects and evaluate anode performance, FiGS® is a critical tool to ensure structural integrity and extend the operational lifetime of any underwater structure that requires the use of a cathodic protection system, quickly and cost-effectively.
Subsea integrity management
FiGS® contributes to effective subsea asset management by providing detailed insights into the corrosion protection status, supporting data-driven maintenance and risk management strategies across an entire development.
New generation AUV operations
FiGS® integrates seamlessly with new generation AUVs and resident drones for on-demand, advanced, high-speed cathodic protection surveys that maximize operational efficiency and data accuracy while significantly reducing costs related to cathodic protection maintenance.
Gravity based structures
Enhancing both the longevity and safety of foundational gravity-based structures, FiGS® provides effective cathodic protection assessments by detecting electric field gradients and current densities, enabling precise evaluations of anodic efficiency and coating integrity.
FPSO / hull / mooring lines
Because FiGS® enables precise detection of coating defects and anode performance quickly, it ensures optimal cathodic protection maintenance, helping to extend the service life of both FPSO hulls and their associated mooring lines.
Offshore wind
FiGS® reduces lifetime cost of operations and maintenance for offshore wind structures with precisely evaluated cathodic protection data (including coating damages and anodic efficiency) integrated within an integrity management system for a single, or multiple wind farms.
Cathodic protection modelling
Because FiGS® has the unique capability to define the direction of electric currents, it enables areas of interest, such as coating damages, faulty anodes, stray currents and more to be pinpointed and visualized. Through this, tangible savings are available by using real-life current densities as opposed to conservative design codes.
With cathodic protection modelling, it’s easy to try out different scenarios in order to ensure the optimal protection of your asset. Typical cases evaluated by cathodic protection modelling include:
Current shadow effects, current drain and anode distribution issues
Uneven anode consumption
Over or under protection
Protection in confined areas, small annuluses, gaps etc.
Galvanic corrosion
Anode interference
Interaction between connected structures
Pipeline attenuation
Ask the experts
FORCE Technology has more than 40 years’ experience at the forefront of cathodic protection design and inspection. Contact us today to find out how we can leverage the leading capabilities of FiGS to reduce your subsea asset lifecycle costs while improving the quality and scope of data acquired.
FiGS® is an award-winning field gradient sensor that can be used to assess the condition of the corrosion protection system (coating combined with cathodic protection) on subsea assets such as pipelines, templates, manifolds, jackets, etc. It is an advanced integrity management inspection tool, with 50 times the detection level of any other technology available. With FiGS® CP survey, maintenance and inspection operations can be planned using a risk based approach on a long-term basis, extending inspection intervals as well as optimising the offshore vessel time and minimising interventions required.
A FiGS® CP inspection provides a full integrity assessment of any subsea assets’ corrosion protection system (coating + CP). FiGS® is a non-contact CP tool that determines current output from anodes, steel current density, current drain to nearby assets (e.g. wells) and more (see list below). We combining FIGS® data with over 40 years of experience in the field of integrity management and cathodic protection, offering you a full overview of the integrity, subsea.
A FiGS® CP survey report includes:
Potential profile plot for pipelines
Potential distribution plot for 3D structures, to identify hotspots/areas of under-protection
Anode current output (pipeline and structure anodes)
Effective steel current density (including coating breakdown for coated pipelines/structures)
Service life expectancy of the CP system in years (i.e. remaining life of sacrificial anodes)
Recommended time to next inspection based on condition of CP system
Current drain (from anodes on pipeline/structures to adjacent structures, e.g. drain to well from anodes on X-mas trees)
Coating damages, with position and current supplied
Based on the above, the need for a CP retrofit can be identified. If a CP retrofit is required, FiGS® data can be used to minimise the extent of retrofit required by basing the retrofit design on steel current density determined by FiGS®; these are typically lower than the CP design requirements of e.g. DNVGL-RB-401 (CP design for structures) or ISO 15589-2 (CP design for pipelines).
As seen in the graphic below, there are several reasons for using FiGS® as an inspection tool.
Conventional methods only provide a potential or field gradient (activity) profile/distribution. FiGS® on the other hand, in combination with CP modelling using FORCE Technology software SeaCorrTM, provides much more information. It reveals anode current output (and hence estimated anode wastage), current density on bare (uncoated) steel, effective current density on coated steel, the presence of coating damages (such as damages to the outer sheath of flexible pipelines and jumpers), as well as current drain from anodes to adjacent structures (e.g. to templates with wells).
FiGS® measures the strength and direction of the electrical fields from anodes to cathodes (coating damages / bare steel). By using two sensors during pipeline inspection, it can be used to triangulate the position of anodes and coating damages. This may prove useful in areas where a traditional pipetracker is not able to track the pipe, due to high burial depth; FiGS® can theoretically triangulate anodes down to 10 meters burial depth. In such cases, FiGS® can aid in locating anode locations for correction of pipe routing. As FiGS® is a passive system, it will not be able to continuously triangulate the pipe like a pipetracker, unless the pipeline coating is continuously heavily damaged, being provided with anode current more or less on a continuous basis.
FiGS® has also been used to locate buried flexible couplings during installation of new flexibles, by locating the anode on the flexible pipe coupling, limiting the excavation to a targeted area.
FiGS® itself does not require contact with the pipeline/structure to create a potential profile/distribution plot; the potential profile is calculated and modelled with Seacorr™. However, to fix the potential profile/distribution there are two techniques that can be used:
Perform a few contact CP stab measurements (e.g. at each end of a flowline) to verify the calculated profile/distribution.
Use the open circuit potential of an anode as reference (e.g. 1050mV exposed and 1000mV buried)
For a CP system in the maintenance (stable) phase, potential data from earlier surveys can be considered.
Both above methods have been proven through numerous validation tests with conventional contact measurements and have been approved through several TRL7 (proven technology) qualification with International O&G majors.
A FiGS® survey can be conducted with an ROV flying at a speed of up to 6 km/h without losing valuable information. This is faster than any other advanced CP inspection tool on the market. FiGS® can also be positioned higher above the pipeline and still obtain valuable data. The increased speed saves costly vessel time, while the larger measurement distance decreases risks associated with the flight of the ROV.
FiGS® can be used on buried, trenched or rock dumped pipelines, obtaining the same information as with an exposed pipeline, see graphic below. Surveys can be performed on pipelines buried down to a depth of 10 m.
FiGS® can be used together with active pipe trackers (e.g. TSS440) since the signals from the pipe tracker does not affect the sensor readings. This feature reduces the offshore time as a pre-survey with a pipe tracker is not required. This results in significant cost savings, mainly related to the vessel rental.
In combination with CP modelling using the FORCE Technology software SeaCorrTM, FiGS® data allows for the assessment of status and life expectancy of the CP systems on entire subsea fields, consisting of pipelines, subsea structures and/or jackets.
A CP survey covering all the assets of a subsea field will identify the interactions between different CP systems, such as anodes on one structure/pipeline providing CP current to an adjacent structure/pipeline, e.g. due to a depleted CP system on the latter. Also, quantifying the current supplied as drain to connected structures that themselves do not require CP, such as platform or subsea wells, will allow for a more accurate prediction of remaining anode life. Such CP drain is typically seen on structures directly connected to wells (templates, X-mas trees, etc.), but also on pipelines, where anodes as far as 10 km away from a template has been seen to supply drain current. In these cases, the pipeline anodes installed right next to the template are already seen as heavily depleted or are predicted to become depleted before the end of the CP design life.
Thus, performing a FiGS® CP survey covering the entire subsea field allows for an assessment of the overall status of the field, effectively identifying areas of concern. Looking at the entire subsea field as one unit instead of several stand-alone units provides valuable information for CP/integrity management. Based on the results in terms of anode remaining life and modelled potential distribution, a risk-based approach to inspection can be selected. This makes it easy to differentiate between CP systems where anode consumption is low and remaining life exceeds the remaining service life (where the interval to the next inspection can be extended), and CP systems with concerns, e.g. regarding drain issues, where more frequent inspections are required. Overall, this equals cost savings since unnecessary CP surveys can be avoided and effort can be focused on specific areas of concern and on identifying when intervention/corrective measures (e.g. CP retrofit) are required. One section of a subsea field with FiGS® data overlaying the model is shown in the graphic below.
A typical FiGS® survey on a subsea structure usually takes 0.5 to 2 hours, depending on the size of the structure and the capabilities of the ROV. A jacket survey will normally take 3 to 12 hours depending on the size of the jacket and the number of anodes installed. The major advantage of FiGS® on structures is the large amount of information obtained over a relatively short amount of time. Data is combined with detailed CP models developed using the FORCE Technology software SeaCorrTM and combined with our extensive experience with CP modelling; this allows for identification of hotspots, e.g. areas of under-protection (see image below), as well as the impact of CP current drain e.g. to wells.
Potential distribution on subsea structure based on FiGS®-areas of under-protection (potentials positive of -800 mV) identified:
The frequently used Cell to Cell technique is based on a twin cell probe with fixed reference electrodes in a distance, typically 30-50 cm. This technology has weaknesses in terms of accuracy because of signal noise, which during post processing is filtered to obtain a smooth line. In this process there is a risk that possible issues like coating damages are not discovered. This can happen because some of the signals are interpreted as noise instead of being picked up as a significant coating damage.
In addition, drifting of Ag/AgCl reference electrodes may also affect the accuracy of measured signals. With a FiGS® CP survey, the noise and drifting of reference electrodes are reduced to negligible levels because the cells are in close inter distance, ca 5 cm and rotate 180 degrees measuring every quarter clock position (4hz). This way, FiGS® can also measure the direction of the field, giving additional valuable information like drain to adjacent structures, pipelines etc. FiGS® does not require any form of calibration and can be run continuously from start to end of the pipeline/asset.
