Related by context. Frequent words. (Click for all words.) 41 shale deposits 40 geologic formations 40 recoverable 39 geological formations 39 contaminate drinking 39 extractable 39 methane 39 contaminants 39 subsurface 38 shale formations 38 hydrocarbons 38 groundwater 38 USGS 38 reservoirs 37 aquifers 37 carbon sequestration 37 recoverable reserves 37 coalbed methane 37 fracking 37 coal seams 37 Groundwater 37 wells 36 fracing 36 gas hydrates 36 hydraulic fracturing 36 tailings ponds 35 Hydraulic fracturing 35 aquifer 35 Tittel 35 underground aquifers 35 wellhead 35 Ogallala Aquifer 34 valley fills 34 tritium 34 underground aquifer 34 wellbore 34 Pinedale Anticline 34 toxic pollutants 34 Bakken formation 33 hydrofluoric acid 33 arsenic contamination 33 placer gold 33 frack 33 groundwater contamination 33 condensate 33 Dziak 33 contaminated groundwater 33 Methane 33 mine tailings 33 COGCC 33 toxic chemicals 33 Berlant 32 EOR 32 drillers 32 sedimentary rock 32 alluvial gold 32 groundwater pumping 32 Deepwater Horizon 32 Safe Drinking Water 32 sage grouse habitat 32 perchlorethylene 32 hydrogen sulphide 32 watersheds 32 categorical exclusions 32 Athabasca River 32 Aquifer 32 drilling 32 shale 32 mined 32 earth crust 32 extracting 32 drillings 32 coal gasification 31 Fracking 31 wells drilled 31 radioactive tritium 31 DEQ 31 deepwater wells 31 tar sands 31 BOEMRE 31 minerals 31 coal slurry 31 underground piping 31 trillion cubic feet 31 perc 31 directional drilling 31 NPRA 31 methane gas 31 storing 31 hydrocarbon 31 Earth crust 31 dispersants 31 hexavalent chromium 31 carbon capture 31 drilling fluids 31 tcf 31 Tcf 31 shale gas 31 spills 31 Powder River Basin 31 Marcellus Shale formation