Emerson Exchange 365

Twice a week, Dutch natural gas producer NAM was sending operations personnel out to check the integrity of its abandoned gas wells throughout the Netherlands. In many cases this required two hours of driving time plus one hour to conduct a pressure check and upload data, which added up to 300 hours spent on each well every year. Given the large number of wells NAM was legislatively obliged to monitor, the company decided it was time to invest in a solution that would help streamline its operations while ensuring that it remained in compliance.

“We sought to develop a stand-alone, self-contained device to measure process variables on abandoned wells without operators needing to constantly make onsite visits,” said NAM engineer Peter Huiberts, who discussed the remote well monitoring project at the 2014 Emerson Global Users Exchange in Stuttgart, Germany.

“Finding a cost effective answer to the problem posed several unique challenges. We needed to monitor well integrity in areas where external electrical power was not available. Data had to be collected from the well sites several times a day and transmitted quickly and reliably to our Asset Control Centre, which was often many kilometers away.”

NAM partnered with Emerson Process Management to design and deploy a remote measuring device (RMD) at each well site. The battery RMDs are powered with batteries charged by an onboard wind turbine and solar cell array.

“An onboard wind turbine and solar cell array charges the RMDs' batteries, which power a wireless gateway linked to several Rosemount pressure transmitters mounted on the well heads,” Huiberts explained. “The sensors transmit process values to the RMD during four one-and-a-half hour measurement cycles every day, in between which the system enters 'sleep mode' to conserve energy.”

The devices, which can operate on battery power for up to 11 days without sun or wind, are connected wirelessly over the KPN Telephone cellular network to a firewalled server on NAM’s network at the Asset Control Centre. As part of a preventive maintenance program, Emerson services the RMDs on an annual basis with rotated parts and a new battery pack. “We currently have plans to install additional batteries to allow for continuous measurement capability, which we could possibly use during the well drilling process in the future,” Huiberts added.

“We're now able to check our abandoned well sites four times a day instead of twice a week without operators having to spend hours on the road driving out to the well sites. In addition to saving thousands of man hours every year, we estimate that we've already recouped about 90 percent of our original investment through reduced operating costs. And our wells are safer and easier to maintain because of it.”