Building Information Modelling: designing and maintaining offshore rigs

The words building information modelling may not inspire passion in the hearts of people working in construction, but they have become commonplace in the industry. A government mandate issued this year has made BIM, a construction tool which embeds product and asset data into a 3D computer model, a requirement for all centrally secured projects. If BIM is so important to the construction industry, could its uses translate to the offshore industry?


Offshore

Building information modelling (BIM) has been heralded as a cutter of costs, saviour of client, contractor and supplier relationships and an operator's dream in the construction sector. A system that first started out as a modelling programme, it has grown into a project process, ensuring all data on a project is stored on a 3D model, and is now used from design, right through to the operation of any asset.

The original idea of a common model to hold all information on a project has achieved significant backing from the UK Government, which has set up a specialist BIM task group with the aim of installing BIM into all projects where it could provide benefits. Over the past five years, the task group has transformed the definition of BIM to a set of processes conceived to help multiple fragmented stakeholders work together more easily, preventing snags, cutting costs and saving time.

As the price of oil continues to fall, industry experts are casting around for industries the offshore oil sector can learn from, one of which is construction. Richard Fletcher, managing director of UK-based Trimble, a BIM systems provider, says there are comparisons to be drawn between complex construction projects and rig building. "You could argue that something in the middle of the North Sea is not that dissimilar to something in the middle of London," he says. "You are very limited on space and time and the environment isn't ideal in either instance."

"As the price of oil continues to fall, industry experts are casting around for industries the offshore oil sector can learn from."

According to Fletcher, this is where BIM comes in. BIM models combine graphic, physical, commercial, environmental and operational data in one 3D model, for all parties involved in a project to use. The wider benefits of this interoperability are the elimination of clashes in construction and installation schedules, less rework, minimisation of waste due to more accurate models, and evolving asset data for operations and maintenance.

Is BIM suitable for offshore?

"The pieces of design software that offshore companies tend to use would either be PDMS or Intergraph's SmartPlant 3D, both of which produce excellent plant models...but neither of which are able to do fabrication levels of detail on a structural model," Fletcher explains. A BIM programme is therefore designed to take all the information from the PDMS and combine it with detailed structural information in a format that anyone can view. BIM can also incorporate information from finite element method analysis, a type of standard steel testing used in offshore rig construction.

There are a small number of companies bringing BIM to the offshore oil industry, branching out from bigger operations in the mainstream construction industry. Trimble's Tekla Structures software required only a change in file format to become suitable for offshore, and Autodesk has had success with its Navisworks software in partnership with StatoilHydro. Fletcher says BIM can save a considerable amount of time in producing full models compared to traditional 2D models, because the generation of fabrication information is automated.

In terms of specific benefits to the offshore oil industry, BIM also saves on material usage. Fletcher provides an example: "Because we can create much more accurate material take-off and send that information to optimising software, we find that the stock lengths of seal can be much better used by using nesting tools from the information for the software than by using manual take-off."

In construction of the rig, there are also potential safety benefits to be gained from BIM's ability to help users plan works accurately, in conjunction with sub-contractors and designers. "One of the key features of the [Tekla] software is that you can provide the centre of gravity point on any assembled item," says Fletcher. "So if you are lifting something into place, you can put the lift shackles on the exact centre of gravity so there is no chance of it tipping one way or the other." Within a BIM model, the swing of different cranes can also be tested, to select the right one to ship out to the rig, saving time and cost.

There are obvious uses for BIM when a holistic approach is taken to all rigs under a company's remit. Similar structures can provide new lessons each time they are constructed, and BIM models can bring this learning onto an active model. This will ensure the next rig to be built is better, more efficient and cheaper than the last, by ensuring that mistakes aren't made twice, efficiencies are sought out and that lessons learned are captured in one place.

Should it be applied to offshore?

Ray Crotty, director at consultancy firm C3 Systems Limited and author of The Impact of Building Information Modelling: Transforming Construction disagrees with Fletcher. He argues there is no place for BIM in the offshore sector; in fact, using BIM could even endanger rig workers.

Offshore rig projects are far less fragmented than onshore construction projects. The owner of a rig usually commissions a contractor under an engineering, procurement, and construction (EPC) contract to run the process from start to operation. This generally includes sourcing vendor data from specialist manufacturers of equipment, completing the process design, planned layouts, structural design and much more in house, according to company standards. As the majority of the work and information is created in-house, there is no need for a BIM system or process, as all information will be compatible regardless.

"Crotty compares the new emphasis on BIM to many other initiatives which have since fallen by the wayside."

Crotty compares the new emphasis on BIM to many other initiatives which have since fallen by the wayside, many of which share the same aims. "I remember back in the 1990s there was a thing called CRINE [Cost Reduction in New Era] which was trying to do a lot of the things BIM is trying to do now," he says. "It died a death."

In terms of operation of the rig, Crotty maintains that BIM could have a net negative effect in the offshore context, because to make it work, companies must introduce "a whole new set of overheads and a new bunch of box-ticking procedures that are not actually value-creating." The reason it doesn't create value in the operation of the rig is that operations staff "don't need fancy visualisations of the platform they are working with - they've been there and done that."

Fletcher believes there are value-adding uses for BIM in maintenance and operation. By having a complete 3D model, engineers and rig workers can do 'walkthroughs' of any maintenance tasks before they reach the rig. "This gives them an idea of the environment they will be working in, in the digital space, before they actually have to go out to a rig and work in the physical space," he says. "Being able to create method statements based on 3D information is often better than an attempt to do it on 2D drawings."

Why BIM hasn't permeated offshore

This difference of opinion reflects an ongoing conversation within the industry about the efficacy of BIM in the offshore sector. So far, uptake has been slow. Fletcher thinks the combination of the inherent conservatism of the industry and a long period of low oil prices has dampened interest in BIM technology and processes.

By his own admission, "our software isn't exactly cheap, so when you are maybe looking to reduce costs, bringing in a new software title with the associated training and the associated work process changes that would be involved, there may not be the capital to be able to do that currently."

Crotty isn't convinced by the safety argument, as there are problems with keeping the BIM model updated during the operation phase. "They often won't have CAD or Aviva operators out there able to do those updates," Crotty asserts. "Unless somehow you can keep the model and the physical platform completely in sync, the model becomes dangerous, a source of error, a potential risk."

The offshore industry, especially in the UK, is undoubtedly in turmoil. As it looks for ways to cut costs and extract more, perhaps it needs to take a long hard look at itself and come up with solutions specifically tailored to meet its needs. BIM can probably meet some of them, but the cost hasn't yet been proven to provide the value required.