Fort Morgan Gas Storage Field

The Fort Morgan Gas Storage Field (Field) is located approximately 5 miles south of Fort Morgan, Colorado in Morgan County and is operated by Colorado Interstate Gas (CIG), an El Paso Corporation. On October 22, 2006, COGCC staff was notified of a casing leak on Well #26 that had necessitated the evacuation of nearby residents. The gas flow from the well was safely shut off on October 22, 2006, and there were no personal injuries. CIG estimates that between 650 and 700 MMcf were lost based on inventory analysis, flow calculations, and chart measurement. Two nearby residences remain evacuated; residence H100 located approximately 1,000 feet east of the compressor facility, and residence H101 located approximately 1,400 feet southeast of the facility.

CIG has collected samples from over 50 domestic water wells within a 3-mile radius of Well #26. Residence H100 is the only domestic water well where dissolved methane was detected at concentrations greater than 2 milligrams per liter (mg/l), which is a theoretical threshold concentration at which there exists a potential for methane to accumulate to potentially explosive levels in unventilated areas. Methane was detected in the samples collected on February 20, March 23, May 15, June 21, and July 19, 2007, at concentrations of 19 mg/l, 26 mg/l, 9.9 mg/l, 23 mg/l and 21 mg/l, respectively. Benzene was also detected in the sample collected from the water well at residence H100 on February 20, May 15, and June 21, 2007, at a concentration of 2.0 micrograms per liter (μg/l), 2.7 μg/l, and 3.0 μg/l, respectively.

The Colorado Basic Standards for Ground Water for benzene is 5.0 μg/l. Trace concentrations of BTEX compounds were also detected in four other water wells. A total of 85 cone penetrometer test (CPT) borings were advanced across the field area. Seventy-eight of these were completed in the shallow aquifer zone and 7 were completed in the deep aquifer zone. Dissolved methane was detected in 15 CPT piezometers at concentrations greater than 2 mg/l during the pre-irrigation sampling event in March 2007 and in 9 CPT piezometers during the post-irrigation sampling event in June 2007. Benzene was detected in 3 CPT piezometers during the June 2007 sampling event. The benzene concentration in CPT 41D was 6.0 μg/l, which exceeds the Colorado Basic Standard for Ground Water.