Coalbed Methane Produced Water In The Western Us

Mining (DOGM) and its policymaking body, the Utah Board of Oil, Gas, and Mining,37 which also has primacy for the UIC program for Class II injection wells (Table 3.1).

The operator must take "all reasonable precautions" to avoid polluting lands, reservoirs, natural drainage ways, and groundwater sources. With respect to CBM operations, produced water is generally considered by Utah to be a "byproduct" of oil and gas production, thus falling under the jurisdiction of the DOGM. Such produced water must be disposed of in compliance with all applicable state, federal, or local regulations. However, in some circumstances the State Engineer's Office may authorize temporary water rights to allow produced waters from mining operations (including CBM produced water) to be put to beneficial use once it has been diverted from its underground location (Bryner, 2002). Because much of Utah is closed to new appropriations of water, new projects and allocations require acquisition and amendment of existing rights for new purposes (BLM, 2001b).

Most CBM produced water in Utah is not potable without treatment and is disposed of by reinjection into subsurface formations. Operators may choose to dispose of produced waters via subsurface injection in Class II wells under the state UIC program (Bryner, 2002). Although state regulations do not specifically address CBM produced waters, the DOGM has rules that address the disposal of "saltwater and oil field wastes," which include CBM produced water.

As of November 2009, the Utah Administrative Code set out the permitting rules for lined and unlined wastewater disposal pits (Rule R6949-9, Waste Management and Disposal).38 The rules describe various requirements for wastewater disposal pits, both lined and unlined, including geological and hydrogeological constraints for locating the pits; parameters for the type and thickness of the lining for lined pits; testing subsurface conditions prior to construction; climate considerations (to gauge, for example, evaporation and precipitation in the location of the pit); the daily water quantity to be disposed of, and water quality analyses, including the chemical constituents of the produced water relative to local groundwater. Disposal of CBM produced water in an unlined impoundment may be permitted by the DOGM if the disposal does not demonstrate pollution potential to surface or groundwater and that the disposal meets one or more of the following criteria: (1) the produced water does not have TDS in excess of local groundwater and does not contain objectionable levels of chlorides, certain organic compounds, or sulfates; (2) most or all of the water is to be used for beneficial purposes such as irrigation, livestock or wildlife watering and produced water analysis indicates that the water is appropriate for the intended use; and/or (3) the volume of produced water to be disposed is less than 5 barrels per day per month. If beneficial use is the basis for the application for an unlined pit, written confirmation from the users should also be submitted. The responsibility for conducting the

37See ogm.utah.gov/ (accessed March 4, 2010).

38See www.rules.utah.gov/publicat/code/r649/r649-009.htm#T3 (accessed March 4, 2010).

analyses for permit applications and for subsequent compliance for disposal impoundments lies with the permit applicant.

Colorado

The Office of the State Engineer (Division of Water Resources [DWR]) of the Colorado Department of Natural Resources administers the diversion and use of surface waters and groundwater of the state, including groundwater withdrawal for beneficial use (see Table 3.1). The Colorado Department of Public Health and Environment Water Quality Control Division (WQCD) has authority over environmental laws related to waste discharges to surface waters, including produced water from CBM operations.39 The Colorado Oil and Gas Conservation Commission (COGCC) is the primary state regulatory authority over oil and gas activities in the state and until recently maintained jurisdiction over produced water from CBM operations under the state standards established for general oil and gas exploration and production. The COGCC generally has considered produced water to be a byproduct and defined it as a "waste" from exploration and production under Rule 907 (Rein, 2009; Stednick et al., 2010). Under this definition, CBM operators have thus not been required to obtain a permit from the Office of the State Engineer to withdraw the produced water since it was a "waste product" of the methane extraction process.

COGCC's Rule 907 describes how produced water should be managed and disposed of: (1) subsurface reinjection via a Class II injection well; (2) evaporation or percolation in a lined or unlined pit; (3) disposal at a commercial facility; (4) disposal via surface discharge through road spreading (outside sensitive areas); (5) discharge into waters of the state (under rules of the WQCD); (6) reuse of the water for enhanced recovery, recycling, or drilling; and (7) treatment to be used as an alternate domestic water supply to surface owners within the oil and gas field (Rein, 2009). Permits through the COGCC (or the WQCD for surface water discharge) are required before an operator may employ any of these disposal methods. As outlined below, the classification of CBM produced water for purposes of regulation changed in the state in 2009 and has implications for industry and for authorities regulating CBM operations and produced water.

Beneficial use of produced water from a CBM well by the operator or another person requires compliance with the water rights acts of the state and requires a water well permit, issued by the State Engineer. A well permit for water from a CBM well presumes that the water is tributary, although the person may submit data to document that the water is nontributary (Wolfe and Graham, 2002).40 Nontributary water is essentially water that is considered isolated, or compartmentalized, with respect to surface water so that its diver-

39See www.netl.doe.gov/technologies/pwmis/regs/state/colorado/index.html (accessed March 4, 2010).

40In a nontributary aquifer a proposed diversion will not deplete surface streams more than 0.1 percent of the proposed diversion volume in any year for up to 100 years (Rein, 2009).

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