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Apr-2015

3D scanning corrrects design clashes

A contractor in Nigeria applied 3D laser scanning to overcome design clashes that had led to postponement of planned revamps in a gas platform

Tracey Murray
AVEVA
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Article Summary
Ariosh can generate accurate, as-built 3D models and drawings, perform virtual installations and generate job cards, a capability that has helped the company to deliver several brownfield projects with the accuracy needed to achieve right first time installation. The most recent example was the laser scanning of several platforms in Nigeria, after a major international owner operator had been forced to halt modification work due to unforeseen design clashes.

In 2012 Ariosh was awarded the contract to provide follow-on engineering services during a revamp of the owner-operator’s seven offshore platforms. Production needed to be stepped up in order to provide approximately 300 million cu ft/d of natural gas feedstock for a refinery that will convert natural gas which was previously being flared into high-value, clean transportation fuels.

With headquarters in Houston, Texas, Ariosh set out to become a leading engineering, procurement, construction and installation (EPCI) company in the West African oil and gas industry. The company has been a pioneer in the use of laser scanning in Nigeria since 2005. It delivered its first construction management project in 2008 and its first EPCI project in 2013. Ariosh’s business remains mostly in brownfield and revamp projects, which contribute 70% of the company’s revenue. The company now operates chiefly in the Gulf of Mexico and in West Africa.

The challenges of executing brownfield projects became 
apparent following the completion of detailed engineering and fabrication drawings by an international EPC. The owner-operator experienced significant clashes during installation of the first modifications on the first platform. They suspended work on the first platform and proceeded to the next one, only to encounter the same problems. Worried that history would repeat itself with the remaining five platforms, the upgrade programme was put on hold. Ariosh was contracted to help recover the situation.

The problems needed to be resolved quickly to avoid the serious impact of increased costs, schedule delays and lost production, as well as safety and reliability concerns. The direct costs alone were heavy; for instance, the barge used for installation cost over 
$100000 each day. Modification work during installation offshore can take at least twice as long as modifications in the fabrication yard.

Solving problems
Ariosh started by laser scanning all seven platforms and then modelling the new design, using Aveva PDMS for the first two and Aveva E3D for the remainder. These 3D models were superimposed on the laser data and clash checked using the built-in clash management capabilities. Design verification, completion of fabrication and fabrication assurance, and installation on the first three platforms was completed in only 18 months.

Design verification should obviously be performed prior to fabrication. However, on this project, fabrication of the spools and structures had progressed to over 70% before Ariosh’s involvement. These spools and structures were then scanned in the fabrication yard to allow Ariosh to conduct virtual installations of the as-fabricated spools to make recommendations for correcting installation issues in advance. Rework was also minimised.

Modifications performed at Idmon, the fabrication yard based in Warri, Nigeria, were also verified by laser scanning. Scans of the modified spools and structures were superimposed on the design models within E3D to ensure compliance with Ariosh’s issued construction drawings. Although it took Idmon about a year to implement all of Ariosh’s recommended corrections, the resulting 98% first-time fit achieved a substantial reduction in overall installation time and provided the owner-operator with a cost saving of around 40%. Clash checking and reporting could all be efficiently performed within Aveva’s single 3D model environment, thus saving Ariosh’s client considerable time and cost during project execution.

Serving a wide client base, Ariosh operates a range of engineering and design solutions. It currently uses Aveva PDMS with Aveva Laser Model Interface (LMI) and Aveva E3D. The company had adopted PDMS in 2010, having used many different 3D design software tools and finding that none provided the versatility and efficiency, especially when handling large and complex 3D models. It has more recently also adopted E3D, which adds more value with its improved Access Platforms, Stairs & Ladders (SLH) modelling and its built-in capacity to read and work with the full laser dataset.

According to Ariosh, PDMS’s integration with laser data (following the add-on of Aveva LMI) is a particular advantage, and many of its commissions specify PDMS for their design.

When E3D was released in 2013, Ariosh saw value in its new capabilities, especially those related to laser scanning. As a result it chose to migrate from PDMS to  E3D, a decision  supported by two-way database compatibility. All potential installation issues, including clashes, can now be more easily identified and resolved, while fabrication issues are avoided through the ability to automatically produce fabrication drawings directly from the E3D design model.

Ariosh started off using PDMS on the first two platforms and then, once E3D was released, the company switched to using E3D on the remaining five. Ariosh required seamless integration of 3D model and laser data for clarity and consistency. The EPC’s objective in selecting E3D was to ensure error-free design and first time fit installation. Ariosh’s laser scanning is now powered by E3D; the team’s experience with other laser data handling software made it easy for them to learn. The self-explanatory laser scan data manual allowed engineers to be operational very quickly.

Outcomes
E3D’s BubbleView technology removed the import/export bottleneck between the 3D design package and the laser data software to obtain a realistic view of laser data within the design model (see Figures 1 to 4). The BubbleView feature improved  productivity by 20% and the quality of deliverables was also higher. The company expects still further increases 
as its designers become 
fully familiar with the E3D interface.

Ariosh has built its work processes around E3D, which has significantly increased efficiency in its design verification process and has delivered improvements to the company’s PipeFit Assurance 
work process. Furthermore, the BubbleView feature of E3D enables synchronisation between 3D model and laser data, which significantly improves design efficiency.

Aveva’s solutions have added significant value to Ariosh’s business processes through features such as the automation of pipe fabrication drawings. The company is currently evaluating the use of Aveva Bocad Steel for structural steel detailing.

Conclusion

Ariosh says that it has invested in the development of its laser scanning capabilities at an opportune time. First, there is significant demand for laser scanning services in Nigeria due to the hundreds of aging onshore and offshore facilities requiring extensive revamp projects, and which generally lack accurate as-built documentation. Many companies planning revamp projects have little or no reliable as-built information and must rely heavily on laser scanning to create this, and for design verification. Second, the Nigerian government’s ‘Stop Routine Gas Flaring’ campaign is driving demand for laser scanning services as operators seek to phase out gas flaring.
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