Technology Making Progress on Frac Water Issues
The boom in shale gas drilling in Pennsylvania and across the U.S. has prompted concerns over the impact of hydraulic fracturing on local water supplies, generating the need for technology to recycle and treat flowback and produced water.
The process of hydraulic fracturing, which involves creating small fractures in the rock surrounding the reservoirs in order to create a path through which the natural gas and oil can flow, has enabled production from oil and gas resources that were otherwise thought unrecoverable.
While hydraulic fracturing increases the production rate of oil and gas wells, the process also uses a substantial amount of freshwater and produces billions of gallons of wastewater each year.
In the Barnett Shale natural gas operations, a little Canadian based company is taking this murky, salty water from hydraulic fracturing of gas wells and recycling it into clear, pure distilled water used to "frack" more wells.
Fountain Quail Water Management has a portable facility with four of its $4 million NOMAD mobile evaporator units. They process wastewater for Devon Energy, the largest Barnett Shale gas producer and a champion of efforts to improve oil field water recycling.
Fountain Quail has recycled more than 500 million gallons of water for reuse in Barnett operations since 2004, said Brent Halldorson, chief operating officer for the company and its parent, Aqua-Pure Ventures, based in Calgary, Alberta. That's enough water to frack 120 gas wells, Halldorson said.
It's been a tough go financially for Fountain Quail in the Barnett. Gas producers find it cheaper to pump wastewater down disposal wells, often called saltwater injection wells, long used by oil and gas operators in Texas. Fountain Quail has also been thwarted by weak natural gas prices, which helped slash Barnett drilling activity more than 50 percent since peaking in 2008.
In Pennsylvania's Marcellus region, however, there are "very limited" options for disposal of well wastewater, because its geology is ill suited for large-scale underground disposal, Halldorson said. Disposal often requires a long drive to Ohio, he said.
"It's cheaper to recycle it," Halldorson said. "That's why it's such an opportunity for us.
How it works
When a Devon Energy gas well in the general vicinity of Fountain Quail's operation is fracked, 10 to 15 percent of the fracking water quickly comes back up the wellbore. This salty "flowback water" can contain dirt, clay, metals, traces of oil and chemicals that were added to the water.
This concoction is taken to Fountain Quail's site on property owned by Devon, then put into a lined, 17,000-barrel capacity "feedwater pit" surrounded by a protective berm. From there it goes through a clarifier that removes solids, leaving essentially salt water, Halldorson said.
The salty water flows to storage tanks and then goes into the NOMAD mobile evaporator units, which boil the water to make steam, which is heated 20 degrees higher by using a steam compressor powered by natural gas that comes from a nearby gas well.
The steam helps power the operation and makes it extremely energy-efficient, Halldorson said.
There are two major end products from the evaporator units: Pure, distilled fresh water, piped to a lined pit that can hold 400,000 barrels, or nearly 17 million gallons, and a concentrated, salty solution that separately flows into two large brine tanks.
Halldorson calls the distilled water "more pure than the bottled water that you buy in a grocery store." It's pumped through 10-inch aluminum pipelines that snake along the ground as much as several miles for the next well.
The brine can be used as a heavy "kill fluid" to contain gas pressure when work needs to be done inside a wellbore or at the surface. What's not used is transported to the nearest saltwater disposal well 10 miles away, Halldorson said.
For every 100 barrels of wastewater recycled, 70 to 85 barrels become fresh water, Halldorson said. The Wise County site can treat 9,200 barrels (386,400 gallons) of water per day, he said.
Fountain Quail primarily recycles flowback water, but also some much-saltier "produced water" belched from Devon wells as they produce natural gas. A well typically generates 50 to 200 barrels of produced water per day, said Jay Ewing, Devon well completion/construction manager for the Barnett Shale.
Devon's recycling
Halldorson and Ewing said they don't know of any Barnett Shale producer other than Devon that recycles large volumes of wastewater, because disposal wells are a cheaper option.
"The base economics, the cost of recycling, is higher than if we took the water straight to disposal," Ewing said. "It's costing us probably in the range of 50 percent more."
On the plus side, he said, "we are generating some [recycled] fresh water that ... obviously has some value to it."
Devon wants to advance water-recycling methods.
"We're helping to prove some technology that could be used in other places," Ewing said. "I definitely believe that water recycling is going to increase throughout the industry."
Fountain Quail previously announced plans to construct a freshwater pipeline that would deliver treated municipal sewage from Weatherford to gas producers needing water for frack jobs. That would reduce the need for using drinking or surface-water supplies for fracking. With drilling activity down, Fountain Quail has put the project on hold, but remains interested.
Corporate giant General Electric could soon provide competition for Fountain Quail in the Marcellus, next year.
GE has introduced a mobile evaporator specifically designed to help natural gas producers recycle untreated waters that result from the hydraulic fracturing process at the well site. GE has offered thermal evaporation technology for over 40 years, but this is the first time that the technology used for the treatment of shale gas frac water has been completed mobilized.
GE’s says that its mobile evaporator will be used for all unconventional gas and frac water applications in regions of the world where shale gas can be found, including North America, Europe, China and Indonesia. Initial applications will be in various North American markets such as the Marcellus Shale reservoirs located in the Appalachian Basin.
Source: Fort Worth Star Telegram