It’s not perpetual motion, but maybe it’s a runner up. The natural gas experts at Encana, along with the engineers from Ensign Energy Services, have developed a new method of running their natural gas drilling rigs on… natural gas. But not only are the rigs running on gas, they’re running on the same gas they extract from the ground.

 By Jonas Wright, Contributing Writer

 The technology has been brought to a new level at Encana’s work in Jonah Field, a prolific natural gas site in southwest Wyoming. Gas is extracted, treated and returned to the rigs to continue work. “Encana has been working with natural gas fueled drilling rigs since third quarter 2005,” said Sherri Zeller, a special projects engineer at the company.

“Drilling wells with natural gas-powered rigs in Jonah has been a great success, and Encana is propagating that experience and success to other areas of our company.”

Natural gas, like oil, requires refinement before it reaches its full energy potential. But refining raw gas is not as intensive as the cumbersome process of turning petroleum into gasoline or diesel.

Gas extracted on site is sent to a centralized point that includes facilities needed to treat the raw fuel. The gas is then returned to the rig site, where minimal additional conditioning is done. The fuel is then ready for use in the natural gas power drilling rig.

 Leading By Example

 In some sense, natural gas has been a victim of its own success. Within the last year, large new supplies of natural gas have led to prices that have varied from nearly $5.25 per MMBTU (million British Thermal Units) in late June and early July to $3.25 per MMBTU in late October.  

“In Jan of 2009 our CEO realized that the abundance of shale gas was going to create gas surpluses that would exceed the historic demand for natural gas,” said Sherrie Merrow, external relations lead forEncana’s Natural Gas Economy team.

By converting rigs, Encana became a consumer of its own surplus. As an added bonus, Encana was able not only to show off natural gas by using it at the drill site, it also began converting its vehicle fleet to run on the fuel.

“There’s strategic alignment with our company initiative to advance natural gas as a transportation fuel,” Zeller said. “The abundant supply makes natural gas a preferred fuel of choice. Encana is leading by example.”

The rigs, designed by Canada-based Ensign Energy Services, (a wholly-owned subsidiary Ensign United States Drilling, Inc., located in Colorado) have benefits beyond the economics. Having a field that produces cleaner energy is a win for both Encana and the communities where it operates.

Environmental Benefits

“One of the visual signs that you can tell right away is the lack of a black exhaust (typical of diesel engines) plume coming off the engines,” said David Stewart, Encana’s lead for environment, health and safety in the Jonah Field.  These engines emit less than one gram of NO_X per brake horse-power hour (four times less than the 2008 new diesel emissions standards for engines in this class). The Jonah operations team achieved significantly decreased emissions using innovation and engineering.

Air quality, especially during cold weather, is a concern for Sublette County and Pinedale, Wyo., Stewart said. Sublette County has documented winter time ozone events and a concern with visibility in neighboring Wilderness areas.  “This project was the cornerstone to our air quality mitigation efforts” he said.

The improvements, Stewart said, were hard fought. But having overcome the technical hurdles of using natural gas to power the rigs, has given Encana a leg up on the competition. Switching fuel from diesel to natural gas reduced operating costs so much that the new rigs would pay for themselves in one year of continuous operation.

As word of the technology spreads, interest has been percolating over Encana’s natural gas powered rig fleet. Tours have been given to groups ranging from local city councils, other operators, Congressional offices and even to Lisa Jackson (Chief Administrator of the Environmental Protection Agency).

“Everyone is very impressed with the technology and how the Jonah Operations team overcame obstacles to implement the technology,” Stewart said. “It shows that we’re an industry leader and committed to innovation for the purpose of both reducing our impact on the environment and trimming our operating costs.”