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Asset integrity from the start

Written by  Gregory Hale Friday, 01 January 2016 00:00

Greg Hale takes a look at how Shell integrated an asset integrity program into its new Prelude FLNG project with the intent of saving millions over the next 20-25 years.

Integrating an asset integrity program from the beginning will save Shell millions of dollars with its Prelude Floating liquefied natural gas vessel which is now undergoing commissioning. Photos from Shell.

Thinking ahead and integrating an asset integrity program from the beginning will save Shell millions of dollars with its Prelude Floating liquefied natural gas (FLNG) project over the next 20-25 years.

“Shell has been thinking about it from the beginning,” said Scott Hokeness, business development manager at Emerson Process Management. “They realized they will have a limited staff on the ship. From the start, they knew they would be monitoring assets from onshore and supporting a skeleton team on the ship with information on what repairs are needed and what the priorities are. They had this in mind from the start, so as they are configuring their smart devices, they are very careful to set up their alerts from the get go, so when the ship goes on station, they will be ready to monitor it from shore.”

With the industry in a tailspin and profits running tight these days, operators need to squeeze and pull as much out of systems and that is where asset integrity shines.

Definitions of asset integrity abound, but essentially it is the ability of an asset to perform its required function effectively and efficiently while protecting health, safety and the environment when required over the entire lifecycle of the asset.

“The most common view of asset integrity is getting good values from the device as it is working with control strategies and process monitoring,” Hokeness said.

What makes the Shell project interesting from an asset integrity point of view is the oil and gas giant is incorporating it in from the beginning and not just bolting it on.

“More and more we see (users) from the start designing the projects to take advantage of smart instrumentation and the diagnostics that come with them,” Hokeness said. “Shell has taken the strongest stance I have seen where they have designed their maintenance exclusively around the smart instrumentation and the diagnostics that come with them. Traditionally many plants will run to failure and then schedule maintenance.”

“Without a doubt, if you can fix (equipment) before it fails you don’t incur the cost of downtime for the process. If you can schedule work during turnarounds or scheduled downtime, that is far more cost effective than having to shut the process down to repair it,” Hokeness said.

Prelude to a floating plant

Once it is up and running, the Prelude FLNG facility will produce at least 5.3 MTPA of liquids: 3.6 MTPA of LNG, 1.3 MTPA of condensate (equivalent to 35,000 b/d) and 0.4 MTPA of liquefied petroleum gas (LPG).

The floating facility will chill natural gas produced at the field to -162°C (-260°F), shrinking its volume by 600 times so it can ship out to customers in other parts of the world.

Ocean-going carriers will load the LNG as well as other liquid by-products (condensate and LPG) for delivery to market.

The Prelude FLNG facility will be 488m (1600ft) long, 74m (240ft) wide and along with its contents, will weigh around 600,000-tonne. It will be the largest floating offshore facility in the world.

Once construction is completed sometime next year, Shell will tow the facility to its location, around 300mi northeast of Broome, Western Australia.

The facility will then end up moored and connected to the undersea infrastructure and the whole production system will be commissioned.

It will remain permanently moored at the location for between 20-25 years before needing to dock for inspection and overhaul.

Technologies Shell will use on the FLNG facility are ones used successfully onshore, but the company had to adapt or modify some of them in order for the processes, such as liquefaction and offloading, to run at sea.

“This has never been done before,” said Neil Gilmour, Shell vice president Integrated Gas Development in a published report. “We had to find ways to adapt our technology for offshore.”

“From a smart device perspective, they will be able to monitor the health of all of their Foundation fieldbus and HART devices,” Hokeness said. “They have primarily been using fieldbus for their basic control and HART for their safety systems.”

Shell’s FLNG also allows for:

  • High production rates of up to 6 MTPA of liquids (including LNG, LPG and condensate)
  • A wide range of gas compositions and can export LPG and condensate
  • An efficient double mixed refrigerant liquefaction cycle
  • The ability to stay on station and not have to be moved during severe weather conditions such as cyclones, which will increase the availability of the plant

New approach

Moving toward an asset integrity program, Shell had to think about making some changes and not remaining with the status quo. That started with using smart technology.

“They changed their work practices during the commissioning part of the project,” Hokeness said. “They are using the intelligence from their devices right away. When they were commissioning their valves they turned the alerts to make sure they had sufficient air pressure and the valves move the way they are supposed to.

“They do that all upfront and that is a change from the past where they wouldn’t necessarily look at the device until they went online with the project,” he continued. “They are seeing some tremendous savings using the bulk commissioning tools we collaborated on and implemented in the AMS Device Manager software. If they had 100 pressure transmitters configured the same, we are now able to push the configuration to them, push the alarm set up to them and do it all in one go. This new functionality has produced phenomenal savings. It makes sure the smart devices are consistently configured and the right alerts are turned on.”

Shell also worked with the engineering contractors (EPCs) to get them on the same page.

“They told me they worked with their EPCs to change their work practices to use the new tools. That was a step away from how it used to be done. The contractor usually does it their own way, but Shell worked hand in hand with them on the new strategies.”

While the industry is down now, it will eventually come back, but will asset integrity remain a focal point for users or will it fade away as profits start to rise?

“Even when the market does come back, people will continue to care. We have seen increased focus on asset integrity even before the oil and gas market has gone down,” Hokeness said. “It may be more appreciated now because there are fewer capital projects. There is more focus on reliability and getting the most out of what you have.”

Greg Hale is the editor and founder of Industrial Safety and Security Source (ISSSource.com) and is also the contributing automation editor at Offshore Engineer.

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