5 Colo. Code Regs. § 1002-42.31
SPECIFIC STATUTORY AUTHORITY
The provisions of C.R.S. 25-8-202; 25-8-203; and 25-8-204 provide the specific statutory authority for adoption of these regulatory provisions. The Commission has adopted in compliance with C.R.S. 24-4-103(4) the following statement of basis and purpose.
STATEMENT OF BASIS AND PURPOSE
As a result of this hearing, the Commission applied the classification of limited use and quality to the ground water contained within the following specified area:
Moffat County (Figure 53) The Tertiary age Wasatch Formation within a specified area of Moffat County, Colorado (Hiawatha Field) in which extensive oil and natural gas exploration and development has occurred. The specified area includes approximately 3 square miles in Moffat County, Colorado.
The adoption of this Limited Use and Quality classification by the Commission does not preclude the need for obtaining an aquifer exemption under the Underground Injection Control (UIC) program, if future applicants wish to inject fluids into portions of the subject formation within each specified area for which an aquifer exemption would be needed. That is, the adoption of this classification does not preclude the need for compliance with the specific requirements of the UIC program.
Site-specific classification of ground water begins with the identification of the use of the water within the four specified areas as follows:
Moffat County (Figure 53) The confined ground water in the Middle Sand zone of the Tertiary age Wasatch Formation at Hiawatha Field is co-produced with oil and natural gas and is considered a waste. Within the specified area, ground water in the Middle Oil Sand of the Wasatch Formation is not currently used nor can it reasonably be expected to be used in the future for domestic or agricultural purposes. The ground water is not in communication with any surface water bodies within the specified area so that the water quality standards of any classified surface water bodies are not affected by this ground water. More specific evidence of the limited use and quality of this ground water follows:
Within the specified area there are 3 water wells permitted with the Office of the State Engineer. All three of the permitted water wells have been installed by Wexpro (operator of the Hiawatha Middle Oil Sand Unit Injection project) for make-up water for their enhanced oil production project.
The Division of Water Resources data indicates that there are no public water systems, or domestic, agricultural, commercial water wells completed in the Wasatch Formation within the specified area.
The Middle Oil Sand zone of the Wasatch Formation contains or has contained naturally occurring accumulations of crude oil and natural gas, in addition to ground water this specified area. These oil and gas resources have been developed and produced since the 1930's.
Within the specified area approximately 26 oil and gas wells or tests have been drilled to or completed in the Middle Oil Sand zone of the Wasatch Formation.
Within the specified area the Colorado Oil and Gas Conservation Commission (COGCC) has not granted any aquifer exemptions for UIC projects under Rule 324(B) of the Rules and Regulations, Rules of Practice and Procedure (2 CCR 404-1), pursuant to the Colorado Oil and Gas Conservation Act, Title 60, Article 34, C.R.S. (1982). One enhanced oil production injection project (Hiawatha Middle Sand Unit [COGCC Injection Facility No. 150230]) and one water disposal project (COGCC Injection Facility No. 150060) have been permitted within the specified area; however, nether project required an aquifer exemption, because the total dissolved solids (TDS) concentrations of the injection zone (Middle Oil Sand zone) exceed 10,000 milligrams per liter (mg/l). These two injection projects contain a total of four injection wells completed in the Middle Oil Sand zone of the Wasatch Formation.
Middle Oil Sand Zone of the Wasatch Formation
Within the specified area the Middle Oil Sand zone of the Wasatch Formation is between 2,200 to 2,320 feet below the ground surface (fbgs).
Based on information available to the COGCC, within the specified area the TDS concentration of the Middle Oil Sand zone of the Wasatch Formation ranges from 38,500 mg/l to 39,000 mg/l with an average of 38,750 mg/l.
Hydrogeologic data including produced water quality and depth of the Middle Oil Sand zone of the Wasatch Formation and other COGCC data indicate that the ground water in this formation meets the criteria in Regulation 41 for classification as "Limited Use and Quality" . The Commission, therefore, concluded that the application of the "Limited Use and Quality" classification to the ground water within the Middle Oil Sand zone of the Wasatch Formation in the specified area is appropriate. This classification and the application of site-specific standards for organic chemicals assure consistency between implementation of the UIC Program requirements and WQCC Standards and Classifications.
Consistent with the "Limited Use and Quality" classification, the ground water quality standards in Tables 1 through 4 of the Basic Standards for Ground Water, 41.0 will not apply within the specified area. Additionally, the ground water organic chemical standards included in Table A of Section 41.5.C.3 of the Basic Standards for Ground Water (5 CCR 1002-41) for benzene, toluene, ethylbenzene, xylenes, and benzo(a)pyrene will not apply to certain oil and gas producing formations within the specified areas. However, to provide some protection of the potential future use of water resources in the specified area, the Commission's action provides that the statewide standard for radionuclides, as well as the statewide organic chemical standards (other than those for benzene, toluene, ethylbenzene, xylenes, and benzo(a)pyrene) will continue to apply to this ground water.
PARTY STATUS/MAILING LIST STATUS FOR MARCH, 2004 RULEMAKING HEARING
5 CCR 1002-42.31