3D visualization for LoF asset integrity management
Simon Marr
VisualSoft
Offshore assets such as pipelines, structures, subsea production facilities, and FPSOs all require periodic inspections and condition monitoring to detect and assess damage and degradation. Different inspection campaigns are required for each type of asset, so it is difficult and time-consuming for field operators to get the complete picture of the condition and inspection status of all their assets. These inspections generate immense volumes of data over the life of a field or specific asset. Seamless data acquisition and management practices are evolving to meet the need for a more integrated approach to inspection data management.
As offshore installations reach or exceed their original design life and as they decline and become more expensive to maintain, operators increasingly focus on best practices to extend longevity whilst ensuring continued value for money, balancing productivity with maintenance over the remaining life of the asset.
For example, different types of assets have different risk factors and regulatory requirements, so the scope, frequency, and inspections are tailored to the type and age of the asset:
- Pipeline inspections evaluate the condition of external coatings, measure the effectiveness of the cathodic protection system, and assess seabed conditions where currents can cause scour erosion adjacent to pipelines affecting stability and integrity. Visual and acoustic inspections measure lateral displacement and changes in depth of burial and length freespan. A variety of in-line inspection tools are used to locate and assess metal corrosion on the inside wall of the pipe and to check the condition of welds.
- Platform inspections assess the contribution of cyclic loads (wind and waves) to degradation and fatigue. Subsea structures are exposed to extreme conditions which, over time, may result in cracking or weakening welded joints. This can lead to flooded members and reduced structural integrity. Mobile platforms/vessels and their mooring/export systems also must comply with regulatory inspection requirements.
The acquisition of apparently disparate datasets of visual, acoustic, and electromagnetic data and the separate management of that data causes delays and extra effort compiling reports. Correlating different datasets can make it harder to assimilate and understand all the condition maintenance decisions. When decisions are not clear-cut, an over-cautious approach can result in unnecessary repair and maintenance. The challenge facing operators is to choose a cost-effective and efficient inspection and maintenance strategy that minimizes downtime and lost production during repairs whilst managing the maintenance backlog, maintaining a comprehensive audit trail, and building a knowledge base so the condition and maintenance requirements of the assets are well understood at any given time.
Visual inspection surveys
The amount of subsea infrastructure that requires regular inspection increases yearly as decommissioning lags behind construction and as the average lifespan of assets grows. It is no longer acceptable to have degraded or hazardous assets that do not comply with environmental legislation and also pose significant risks in terms of insurance and public relations liabilities.
ROVs are used widely for visual inspections, especially where the environment is too hazardous, extreme, or enclosed for divers to work safely. ROVs offer accuracy, speed of coverage, and 24/7 reliability so they can reduce the time and cost of inspections compared with the use of divers, unless manual intervention or cleaning prior to inspection is required. ROVs are used routinely for pipeline inspection and for inspecting subsea structures, production facilities, or moored installations like FPSOs. Mooring chains, turrets, and interfaces with the seabed touchdown zone now are designed with ROV access to facilitate visual inspection, measurement, and remote intervention.
Asset integrity inspections produce large amounts of information to collect, store, and visualize efficiently and accessibly. Capturing all inspection data in a digital format has become standard practice over the last decade. Operators gain efficiency by using digital storage media for in-service inspection condition monitoring, and this translates into time and cost savings for inspection surveys. The ability to view over the network video from multiple cameras directly from a desktop PC with instant access to any clip or still photograph is the game changer. Within minutes of video being captured, it can be reviewed to enable quicker decisions. Digital video enables viewing of the associated survey/asset information and previous inspection results, allowing the client to search and see all inspection data integrated on a single PC.
Data integration links information from related datasets to give a more complete picture of the condition of an asset. This can be data recorded simultaneously or at different times, but which share a common link such as a time or a geo-referenced position or an asset component identifier. This can include digital video recordings taken at different times to monitor changes in condition by playing several video streams simultaneously or by comparing different historical component datasets
During planning of inspection campaigns there are many benefits from being able to visualize the entire field in a fully immersive 3-D model. The ability to visualize the shape and position of components from any perspective, to focus on specific groups of components, and to show the inspection status, all make it easier to see what is available for inspection and to decide what ought to be inspected. If accurate position information is available, engineers also can determine an optimal inspection sequence to minimize transit time. Model views that show live position updates of the ROV can also be used as a pilot navigation aid around complex fields/structures in low-light or high turbidity conditions.
Field inspection tools
Frequently, a large number of components need to be surveyed during inspection and this requires tools to organize these components into an inspection workscope. Surveys can take weeks or even months and involve shift changes. The risk of overlooking components is smaller for pipeline inspection because there are fewer components and the same pipeline maybe surveyed for many days in a predictable track. Large subsea structures, on the other hand, are more complex with densely grouped components. This makes it much harder to keep track and maintain an audit trial of what has been inspected. This dilemma can be avoided by preparing component task lists within the inspection work scope and marking task completions when conducted. Condition anomalies observed in the video and survey data can be tagged against the component in real-time and then reviewed offline to classify the anomalies and consider remedial action.
Structural inspection view.
For example, during decommissioning it is necessary to consider the degree of corrosion, fouling, and movement of structures to assess whether the planned clear-up procedure is feasible or whether the removal work plan needs to be re-evaluated.
Data management
Inspection surveys done out in a cyclic and structured manner at each stage in the life of a field, from construction through production to abandonment/decommissioning. With production lifecycles now spanning decades, subsea assets are in service longer than anticipated, which leads to accelerated levels and rates of degradation. The HSE KP3 Asset Integrity Management Program reviewed 100 offshore installations and found that inspections often fall behind quickly and operators have difficulty managing the backlog of corrective maintenance.
Operators have been challenged to improve safety and environmental performance while reducing cost during a period when inspections increase. They have met this challenge by taking a risk-based approach to asset integrity management that enables prioritization of inspection for improved asset operation and maintenance.
Condition monitoring priorities are based on a qualitative technical analysis of the individual assets and the environment in which they operate. This approach identifies those components/areas with the greatest risk of failure and focuses monitoring/ intervention on these locations; components/assets at lower risk can be inspected less regularly to optimize the time and budget expended on inspections. This provides an appropriate level of inspection based on the risk of differing systems and the individual components within them. This analytical approach requires appropriate tools to perform the inspections as well as suitable systems to store, analyze, and visualize of the data on which the decision making/analysis will be based.
Implementation of a single database of inspection data for an entire field that links all the seabed, structure, and floating assets together and enables visualization in a simple, unified user interface confers many advantages. By linking assets with survey data and non-spatial information (such as videos, reports, and images), a company GIS database and integrated project environment can be created. Standard and custom reports in company-specific formats can be generated either for a single asset or for all assets in the field.
As an example, inspection engineers may want to visualize the results of the most recent field inspection campaign and to compare the previous campaign to show the extent of condition changes and where continued monitoring or repairs are required. Being able to visualize the whole field enables quicker reviews/analysis and an easier and more direct way to communicate planned maintenance to those who perform repairs such as diver support and ROV teams, as well as to pipeline and platform management.
Conclusion
VisualSoft integrates digital video with GIS datasets using VisualGIS – a plug-in to ESRI’s ArcGIS products – to support an integrated project environment. Year-on-year comparison can be visualized using GIS tools whilst viewing the associated video for the events. VisualWorks integrated with Visual3D-Inspector has been used to visualize historical inspection data from a platform inspection with a view to gaining a more comprehensive picture of the extent of defects to aid future inspection planning. Future surveys can use Visual3D-Inspector from the start to track component inspection records for time-based analysis. VisualSoft is discussing extending trials to field inspections involving multiple platforms, pipelines, and floating productions systems seamlessly linked in a single PC application and database.
The author
Simon Marr is sales manager for Visualsoft Ltd. He graduated with a BEng(Hons) in Electronic and Communication Engineering at Napier University in 1991. He has worked in the Oil & Gas industry for 10 years and has a technical background in real-time process control, diagnostic, monitoring, and visualization systems.
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