Control Upgrade Helps Optimize Well Pad

Canada is the world’s fifth-largest oil producer. This is due, in large part, to the country’s vast reserves in and around Alberta, which contain the third-largest known oil reserves in the world.

Calgary-based ARC Resources Ltd. has called this oil-rich region home for more than 20 years. The company has assets distributed across western Canada and operations that include the exploration, development and production of conventional oil and natural gas.

Just across Alberta’s western border in northeast British Columbia, ARC Resources is one of the largest operators in the Montney region, which is considered one of the best tight gas plays in North America. Tight gas refers to natural gas reservoirs locked in impermeable, hard rock, making the underground formation extremely "tight." It was here that ARC Resources began optimizing the control systems it was using for its large, multi-well natural-gas production sites.

The systems in place at these sites didn’t support artificial lift, a process used on oil wells to increase pressure within the reservoir to help bring oil to the surface; however, artificial lift would be needed soon to maintain production levels. The existing systems also presented both expansion and safety challenges that the company wanted to address.

Operations at a Crossroads

ARC Resources already had optimization programs at its smaller pads that contained only one to four wells. Control systems in place at these pads supported the use of artificial lift systems to help maintain or increase production as these wells depleted.

Larger pads of five or more wells, however, lacked control systems to support artificial lift systems. As some of these sites approached production milestones of 10 to 15 years, the company knew it would need to make improvements in the near future.

“We were very successful with using assisted lift to keep production stable in the smaller fields,” says Charlie Kettner, programming specialist for ARC Resources. “We didn’t have the same optimization option in our bigger pads. So, our production engineers wanted to find a control solution that would allow us to bring artificial lift to these fields, as well.”

The existing controllers couldn’t handle the large amount of I/O required to run the entire well pad. As a result, the company had to use multiple controllers, hardwired together, along with remote terminal units (RTUs). This approach not only made the control infrastructure more complex — and thus more prone to mistakes — but also limited the amount of information available for control and monitoring.

The use of multiple hardwired controllers also presented safety challenges. ARC Resources relies on its control architecture to monitor toxic and explosive gases and to take actions such as turning on an exhaust fan or blocking wells as conditions dictate.

However, the controllers could lock up and freeze their outputs and give no indication of a fault. This forced the company to add “watch dog” timer hardware to monitor for such conditions.

A ‘Canned Package’

Kettner reached out to Rockwell Automation to begin discussions about optimization options that would support artificial lift systems at the large multi-well pads, as well as simplify control and address safety concerns.

Their talks led them to the ConnectedProduction^™ well manager solution from Rockwell Automation, which includes an out-of-the-box Allen-Bradley^® ControlLogix^® programmable automation controller (PAC) and FactoryTalk^® View human-machine interface (HMI) that require no custom coding.

The PAC gives ARC Resources single-platform control for large sites with as many as 32 artificial lift wells and contextualized production information to help operators maintain optimal production levels and troubleshoot issues.

“It’s a canned package,” Kettner says. “You order it, install it and plug in your data to the points it’s looking for, and away you go.”

Kettner and his team decided to pilot the new technology at an eight-well production site named Sunrise near the town of Dawson Creek, British Columbia, before installing it at four other multi-well pad sites.

One of the first benefits they discovered during this trial run was the Add-On Instructions included in the ConnectedProduction solution helped them save approximately two days of programming during the installation process. In addition, because the solution uses an open architecture, integration with other vendor hardware at the site was easy.

Enhanced Visibility and Safety

The ConnectedProduction solution has dispensed with the need for multiple controllers and RTUs that previously were in place at the Sunrise site. Now, all well pad controls have been consolidated into a single control platform. In addition to simplifying the architecture, this will help lower hardware and software costs for the site.

The solution also allows the use of artificial lift systems, including on/off timers and plunger lift systems, and provides visibility into those systems.

“Operators can track events in the ConnectedProduction solution to see what stage we’re in of the optimization cycle and make better decisions about what to do next,” Kettner says. “Operators can see, for example, that a timer well is not producing anymore and move to the next step of putting a plunger in the hole.”

The new system also is helping ARC Resources enhance safety by reducing the risk of faults going undetected at the Sunrise site.

“Now if something goes wrong with the processor or if an I/O rack comes undone, the ControlLogix platform can fault to a safe state where it shuts down all the processes,” Kettner says. “It takes all the power off the solenoids and essentially results in an emergency shutdown.”

Another benefit of the ConnectedProduction system is it can support a flow-measurement card within the control panel. Kettner no longer needs to use a separate flow-measurement computer, which is saving his company tens of thousands of dollars at the site.

“We just plug the card into the rack, and it communicates on the backplane,” Kettner explains. “It’s given us huge cost savings.”

Looking ahead, Kettner already has orders to bring the ConnectedProduction solution to at least four more large multi-well pads in the area.

“We’ve seen the value of the Rockwell Automation solution and want to bring it to our other sites where we need assisted lift,” he notes. “On new pads, we’ll implement this right from day one so it’s there and available when it’s needed, and we can just turn it on.”

Learn about Rockwell Automation Onshore Exploration and Production to optimize the digital oil field.

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