ARC Advisory Group
Since many brownfield offshore production assets lack accurate "as-built" documentation, it is often problematic for engineers to plan, design, and implement needed reconfigurations. Modern laser scanning technology helps to a certain degree, but still requires the engineering group to transform the laser scan data into 3D models of the asset that can be used within their familiar plant design management software (PDMS) environment, a relatively costly and time-consuming process.
Several years ago, the owner-operator of a 25-year-old offshore wellhead platform located in North West Java in Indonesia observed increasing subsidence. This was reducing the distance between the platform's cellar deck and the maximum wave height on this normally unmanned platform, threatening vital equipment and posing a safety threat for operators when on the platform.
As part of a 13-year life extension project, the owner-operator commissioned PT Synergy Engineering to reconfigure the platform, relocate equipment to compensate for the subsidence, and perform additional structural and other modifications as needed to ensure safe operation over the projected lifespan. These extensive brownfield modifications ultimately included reinforcing the existing decks and constructing a new mezzanine deck to house some of the equipment relocated from the cellar deck.
According to Arief Susanto, director at PT Synergy Engineering, the company faced many engineering challenges on this project. First, the only available as-built drawings providing the only documentation basis for the existing facilities had been created 25 years ago when the platform was originally commissioned. These had never been updated. In addition, no drawings existed for either the piping plans/layouts or the electrical and instrument layouts and no datasheets were available for the instrumentation. To make matters worse, the old equipment had no tags, which made it difficult to identify during the survey, and the wellhead control panel had been modified significantly, so it had to be retraced to identify the control logic.
Since the platform was sinking (with the existing boat landing already under water), it had also become very difficult to gain access to the lower sections, making it extremely difficult to take physical measurements.
Previously, Synergy had used laser scanning on a number of projects to produce as-built models as the basis for redesigns. Typically in these projects, the company's laser scanning partner, PT SurtechUtama, would perform the laser scanning to obtain the point cloud data and then convert it to a non-intelligent model for use in the AVEVA PDMS engineering software. Synergy would then use conventional techniques to build in the needed intelligence, such as to import and export PDMS piping, structural elements, and equipment nozzle specifications. This all involved time and cost.
In mid-2011, global engineering software provider AVEVA contacted Synergy's partner, Surtech, seeking its assistance with the beta testing of its new Laser Modeller, designed to transform laser scan data into an intelligent 3D model for use in its own or most other leading suppliers' PDMS software.
Together, Synergy and Surtech decided that the challenging wellhead revamp project would represent an excellent opportunity to test the capability of the new software. For this engagement, Surtech assumed responsibility for performing the actual laser scanning and Synergy for all subsequent engineering work, including applying the laser modeling software to transform the laser-scanned point cloud data into an intelligent 3D model for use within Synergy's software.
Since Synergy had no experience applying either laser modeling or the new software, used to read the cloud point data from the laser scan photos, it would have to learn how to use these solutions from scratch, which is typically a time-consuming process. It would also be necessary to export the company's engineering specifications from its PDMS database into the laser modeling software prior to use.
However, according to Susanto, even though engineering firms such as his own do not typically involve themselves with the "nuts and bolts" of specialized laser scanning-related software, with some assistance from the laser scanning experts at Surtech, Synergy's designers became proficient with the software relatively quickly.
The designers were able to identify the relevant shapes and configurations from Surtech's high-quality point cloud data, use the laser modeling software to generate intelligent 3D models of the structural components and assets, and then import these models into the familiar PDMS software using the interface software.
For any engineering engagement, it is important to distinguish between what could be done using the available tools and resources, and what needs to be done to fulfill the project requirements within the given time and cost constraints.
For this challenging project, Synergy not only used a common-sense, hybrid approach that employed the laser modeling software for the bulk of the modeling requirements, but also used the conventional PDMS environment to provide additional model detail or fine tuning, as required. For example, the main piping lines were modeled directly using the laser modeler, while smaller components such as supports and cable trays were modeled in the conventional design environment.
In addition to modeling compatible, intelligent components, the intelligent PDMS specifications within the laser modeling environment enabled Synergy's designers to calculate weights, centers of gravity and surface areas, as well as generate drawings and isometric projections (using Standard Draft and ISO Draft modules).
Susanto said: "The bubble view software provided a dynamic, high-resolution field of view of the laser-scanned data that reduced perspective distortion and enabled Synergy's designers to place themselves at any scan location and perform zoom, pan, and measure operations within the laser scan environment."
Finally, since the interface software enabled the laser scanned data to be made available within the PDMS environment, it provided a useful tool for performing in-house design and clash reviews, verifying model completeness, and supporting client presentations.
According to Susanto, this new approach enabled PT Synergy Engineering to turn what is traditionally a five-step process into a more efficient four-step process that eliminated the time and effort typically required to remodel the non-intelligent model in the intelligent PDMS environment.
"Once our designers became proficient with the associated laser scanning-related tools, we found that the laser modeling software could save up to 30 or 40% of the time and effort normally required to generate an intelligent model from laser scan surveys," Susanto said. "We particularly saved time on jobs such as 2D drawing production, and in the remodeling of intelligent shapes and objects over laser scanned, non-intelligent ones."
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