MORGANTOWN, WV — A research program funded by the U.S. Department of Energy (DOE) is making significant progress in developing new ways to treat and use water coproduced with oil and natural gas. The ultimate benefit is a two-for-one solution that expects to boost domestic energy supplies while enhancing the Nation’s water supply.
Coproduced water—some of which occurs naturally in subsurface formations, and some that is recovered following injection of water into an oil or gas reservoir to boost production—accounts for 98 percent of all waste generated by U.S. oil and natural gas operations. Produced-water volumes average nine barrels for each barrel of oil produced. Handling, treating, and safely disposing of this produced water has been a tough, costly challenge for oil and natural gas producers for decades. Much of the produced water has high concentrations of minerals or salts that make it unsuitable for beneficial use or surface discharge. An oilfield operator often must reinject such produced water into deep formations, sometimes resorting to costly trucking of the water to deep-injection well sites specially designated by the U.S. Environmental Protection Agency.
More recently, concerns over produced water have threatened to cripple expansion of the Nation’s fastest-growing new source of natural gas supply: coalbed natural gas (CBNG). Much of the water produced in the process of recovering CBNG from coalbeds can be treated and used for crop irrigation, livestock watering, and industrial purposes. But the costs are high. Especially large volumes of produced water are generated in association with CBNG development in the Western states; there is tremendous appeal in turning wastewater from oil and gas operations into a useful product, especially in this arid region where drought is a chronic threat.
DOE’s produced-water research program, which is managed by the National Energy Technology Laboratory (NETL) as part of its Environmental Solutions program, focuses on cost-effective solutions for treating produced water for beneficial uses and limiting production of oil and gas field produced water. The program also assesses and communicates to industry “best management practices” among oil and gas producers coping with this challenge. Three projects under the produced-water program have recently logged key milestones:
- Researchers at Texas A&M University, College Station, Texas, have commercialized a new technology to remove salts and minerals from brackish coproduced water, yielding safe drinking water. The project’s mobile desalination unit can process as much as 10,000 gallons per day of produced water. The technology enables an oilfield operator to re-use about 30 percent of a well’s wastewater stream, reducing the demand on municipal water supplies in a state where diminishing water supply from major aquifers is a growing concern. By slashing the cost of water disposal, it also reduces costs for oilfield operators—potentially to the tune of an estimated $13 million a day for operators in Texas alone. The DOE-funded desalination technology has been officially licensed to GeoPure Water Technologies LLC for commercialization. DOE funded 76 percent of the $459,000 Texas A&M project, which was completed at year-end 2006.
- Researchers at New Mexico Institute of Mining and Technology, Socorro, N.M., submitted a patent application for a breakthrough improvement in the design of zeolite membranes for reverse osmosis. Zeolites are naturally occurring or synthetic minerals with a micro-porous structure. New Mexico Tech’s new synthetic zeolite membranes, used to treat CBNG produced water for beneficial use, are easy to clean, long-lived, and mechanically and chemically more stable than other, comparable synthetic membranes. The project goal is to reduce produced-water salinity by more than 90 percent, making it suitable for agricultural uses. DOE is funding 67 percent of the $1.14 million project, which is slated for completion in September 2007.
- The Interstate Oil & Gas Compact Commission (IOGCC) in cooperation with ALL Consulting, a Tulsa, Okla.–based environmental consultant, has completed a comprehensive new guidebook to the current best management practices for produced water from conventional gas and oil operations. The guidebook, entitled A Guide to Practical Management of Produced Water from Onshore Oil & Gas Operations in the United States, has been published on NETL’s website and on IOGCC’s website. The project also developed an online geographic information system (GIS)–based analysis tool to help producers understand watershed-related regulations and permits and calculate the impacts of produced water in specific areas according to various oil and gas field development scenarios. The online guidebook and GIS tools will help regulatory agencies devise more effective regulations to make water management easier while still maintaining environmental protection. DOE provided funds totaling 80 percent of the $877,000 project cost.
These are only three of the nearly three dozen NETL-managed projects for developing new technologies to increase the beneficial use of produced water, ultimately allowing oil and gas producers to turn a costly waste product into a valuable resource. The upshot: America will see significant gains in the availability of two of her most important resources: energy and water.