The Phase II Hydrogeologic Characterization for the Mamm Creek Field Area is a continuation of the Phase I study for the same area (URS, 2006), which is located south of the Colorado River between the cities of Rifle and Silt, Colorado. The Phase II study included two field sampling tasks. In Task 1, water quality and gas composition and methane stable isotope samples were collected from domestic wells in the Mamm Creek study area that had previously had one or more compounds of concern at or above regulated concentrations, or that had sodiumchloride (Na-Cl) concentrations that suggested possible mixing with Na-Cl water with marine or brackish water characteristics. In Task 2, produced water and natural gas samples were collected from gas wells in the immediate vicinity of domestic wells whose water and gas chemistry sampling results suggested possible potential impacts from deeper formations or other external sources, whether natural or due to natural gas drilling and/or production activities. Phase II of this study was conducted by S.S. Papadopulos & Associates and the final report was published in September 2008. The companion report to the Phase II Study is this Review of Phase II Hydrogeologic Study, interpretations and conclusions prepared by Dr. Geoffrey Thyne, of the University of Wyoming.
| Figure 1.1 |
Location of the Piceance Basin |
| Figure 1.2 |
Area of Investigation |
| Figure 2.1 |
Simplified Stratigraphy |
| Figure 4.1 |
Location of Domestic Water Supply Samples |
| Figure 4.2 |
Natural Gas Well Samples |
| Figure 4.3 |
Nitrate Concentration Distribution in Domestic Wells |
| Figure 4.4 |
Fluoride Concentration Distribution in Domestic Wells |
| Figure 4.5 |
Selenium Concentration Distribution in Domestic Wells |
| Figure 4.6 |
Sulfate Concentration Distribution in Domestic Wells |
| Figure 4.7 |
Chloride Concentration Distribution in Domestic Wells |
| Figure 4.8 |
Total Dissolved Solids Concentration Distribution in Domestic Wells |
| Figure 4.9 |
Dissolved Methane Concentration Distribution in Domestic Wells |
| Figure 4.10 |
Piper Diagram Task 1 Domestic Well Samples by TDS |
| Figure 4.11 |
Piper Diagram Task 1 Domestic Well Samples by Depth |
| Figure 4.12 |
NA/(Ca+Mg) Ratios for Domestic Well Samples |
| Figure 4.13 |
SO4/HCO3 Ratios for Domestic Well Samples |
| Figure 4.14 |
Distribution of Water Types |
| Figure 4.15 |
Piper Diagram Natural Gas Well Produced Water Samples by TDS |
| Figure 4.16 |
Chloride/Bromide Chloride/Boron Ratios vs Chloride Concentrations |
| Figure 4.17 |
Chloride/Strontium Calcium/Strontium Ratios vs Chloride Concentrations |
| Figure 4.18 |
Sulfate vs Chloride Sulfate/Chloride Ratios vs Chloride Concentrations |
| Figure 4.19 |
Carbon & Hydrogen Isotopes of Methane |
| Figure 4.20 |
Comparative Molecular & Isotopic Compositions of Biogenic & Thermogenic Gas |
| Figure 4.21 |
Domestic & Monitoring Wells with Probable Biogenic & Thermogenic Metane |
| Figure 4.22 |
Piper Diagram Comparing Primary Water Samples with QA/QC Results |
