V

Storage and Disposal Options

Reinjection (Deep-Well Injection)

CBM produced water in the Raton-New Mexico, San Juan, Piceance, and Uinta Basins is almost exclusively reinjected into deep, geologic formations, as a means of disposal (Table 4.1). This approach is used in these basins because of the characteristically high

FIGURE Proportional representation of CBM produced water management strategies in the Wyoming and Montana portions of the Powder River Basin. The total amount of water produced in the Wyoming Powder River Basin from CBM extraction in 2008 was approximately 678 million barrels. See also Table 2.1 and Figure 2.8.

SOURCES: Adapted from D. Fischer, presentation to the committee, Denver, CO, March 30, 2009; A. Bobst, Montana Bureau of Mines and Geology, personal communication, December 21, 2009; T. Reid, Montana Department of Environmental Quality, personal communication, December 30, 2009; and J. Zupancic, BeneTerra, Inc., personal communication, December 28, 2009.

NOTE: Chart for Montana correct until May 2010 when the Montana Supreme Court ruled that all CBM produced water must be treated before discharge to Montana streams and rivers.

TDS of the produced water and the relatively low water volume per unit of gas production (Table 2.1; Table 2.2). Geological formations suitable for reinjection in these basins are also well known from historical data associated with water disposal from traditional oil and gas production wells. Treatment by chlorination to address bacterial contamination is required for UIC purposes for deep-well reinjection of CBM produced water. In some cases, filtration of fine particulate material may be required to minimize structural plugging

TABLE 4.2 Commonly Used CBM Produced Water Management Methods, Treatment Requirements and Challenges, and Possible Ancillary Benefits

Management Method

Treatment Requirements and Challenges

Possible Ancillary Benefits

Storage and Disposal Options

Subsurface (deep-well) reinjection for disposal as Class I, II, or V well

Subsurface shallow injection for aquifer storage and recovery

Discharge to ephemeral and perennial streams

Surface impoundments

Land-applied disposal through water spreading

Beneficial Use Options Surface irrigation

Subsurface drip irrigation

Chlorination is required by the UIC program to addres bacterial contamination

May require treatment; dictated by UIC permit requirements; may require chlori nation, filtration, pH adjustment

May require none; dictated by NPDES permit requirements; could require salinity, sodicity, fluoride, barium reductions

Seldom required (Wyoming)

May require pH adjustment; salinity and SAR reductions; soil amendments to facilitate infiltration

Varies from none to pH adjustment, salinity and SAR reductions; soil amendments to facilitate infiltration; ongoing soil quality monitoring

Varies from none to degassing, particulate filtration, pH adjustment, salinity and SAR reductions, chlorination for bacterial control; soil amendments to facilitate hydraulic conductivity

Enhanced hydrocarbon recovery

Aquifer replenishment/storage and/or use as drinking water

Flow augmentation, habitat restoration, wildlife and waterfowl habitat

Shallow alluvial aquifer infiltration

Rangeland habitat improvement, forage production, shallow alluvial aquifer recharge

Rangeland habitat restoration, streamflow augmentation, reduced potential for stream dewatering, facilitation of disturbed-lands reclamation (drill sites, coal mining sites, travel corridor reclamation)

Shallow alluvial aquifer recharge, salt leaching, increased crop or forage production

Livestock watering

Instream flow; habitat enhancement: treatment and discharge to streams/wetlands

Municipal/domestic use, aquifer storage

Industrial

Dependent on water chemistry, intended duration of impoundment, opportunity for mixing or blending with supplemental water sources. In some circumstances, elective or discretionary treatment of water may be voluntarily imposed to lower salinity, reduce concentration of elements known to be toxic or detrimental to livestock health, particularly trace metals

Dictated by NPDES permit requirements; may require salinity, sodicity, fluoride, barium reductions

Dependent on water chemistry and desired use, but may require treatment to drinking water standards; chlorination, particle removal filtration

Varies from no treatment required to reduction of TDS, bicarbonate, and/or other constituents, and temperature and pH adjustment

Wildlife watering, enhanced forage production, enhanced rangeland forage utilization as a result of livestock dispersion and reduced travel distances to water

Habitat maintenance, restoration, wildlife-waterfowl-fishery habitat, flow augmentation to benefit downstream water users

Aquifer storage: future municipal and/or domestic water supply; metal contaminants may adsorb to aquifer and lower dissolved concentrations; less evaporative loss than surface reservoir storage

Reduced demand for withdrawals from existing water supplies

NOTE: NPDES, National Pollutant Discharge Elimination System; SAR, sodium adsorption ratio; TDS, total dissolved solids.

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