Related by context. Frequent words. (Click for all words.) 61 coal seams 54 metamorphic rocks 54 methane crystals 53 coalbed methane wells 52 frac sand 51 Aquifers 51 kerogen 51 porosities 50 Coal seam 50 fumaroles 50 sulphide bearing 50 iron oxides 50 methane 49 sandstone reservoirs 49 groundwater aquifers 49 Georgina Basin 49 fracturing fluids 49 decomposing garbage 49 chlorides 49 steam vents 49 placer deposits 49 geologic formations 49 shallow aquifer 49 earth crust 49 Sulfur dioxide 49 aquifers 48 sedimentary basins 48 deplete oxygen 48 carbonate reservoirs 48 Hydrogen sulfide 48 contaminate groundwater 48 siltstone 48 stratigraphically 48 total dissolved solids 48 silts 48 hornfels 48 coal seam 48 shales 48 dissolved solids 48 Tar sands 47 shale deposits 47 clasts 47 basins 47 glacial till 47 sandstones 47 intermittent streams 47 Sulfate 47 graben 47 naturally occurring radioactive 47 siltstones 47 mudstones 47 Barnett Shale formation 47 uphole 47 geological formations 47 gasified 47 temperature inversions 47 carbonaceous 47 shale formations 47 sedimentary basin 47 magmas 47 Horizontal drilling 46 Upper Cretaceous 46 methane gas 46 combustible gases 46 depositional 46 calcrete 46 Lower Cretaceous 46 lignite coal 46 carbonate rocks 46 underground aquifers 46 alluvial deposits 46 reservoir sands 46 magma chamber 46 propane butane 46 hydrocarbon molecules 46 pyritic 46 tuffs 46 interbedded 46 gas hydrates 46 jasperoid 46 coalbed methane CBM 46 manganese oxide 46 barite 46 wellfields 46 sub bituminous coal 46 reinjection 46 fracking fluid 46 subsurface 46 gravity anomalies 46 Sediments 46 contaminating groundwater 46 benzene toluene 46 sulphide minerals 46 brines 46 gneisses 46 condensate 46 Gippsland Basin 46 sedimentary rock 46 bd.className + = 46 superheated steam 46 seeps