naturally occurring. of thousands of CSG wells. same aquifer so that drawdown stemmed from CSG activities. (up to 200 ft or 60 m) causes Most of that which is not None of these three cases is But acknowledged soap wells to dry up. naturally occurring can be inconsistent with historical, contamination does show that avoided through best-practice natural behaviour of Methane contamination occurs drilling fluids can escape to the well completion. groundwater in the region nor but does not seem to be as aquifer. have they been tied to CSG widespread (report does not Two accounts of grey sediment operations. mention historical methane temporally associated with HF contamination). activities apparently not investigated. Source: US EPA (2004), unless otherwise Table 4.2 Summary of producing US basins from which the EPA registered few or no resident complaints Piceance Basin Uinta Basin Northern Appalachian Western Interior Coal Raton Basin Basin Region Number of Not reported 1255 Not reported 377 Not reported wells in operation (ca. year 2000) Production 1.2 Bcf/y 76 Bcf/y 1.41 Bcf/y 6.5 Bcf/y 31 Bcf/y (year 2000) (34 million m3/y) (2.2 billion m3/y) (40 million m3/y) (185 million m3/y) (880 million m3/y) Size 7225 mi2 14 450 mi2 43 700 mi2 87 000 mi2 2200 mi2 (19 billion m3) (37 billion m3) (113 billion m3) (225 billion m3) (6 billion m3) Depth of wells Two-thirds of wells 1200-4400 ft Most <1000 ft 600-3700 ft 500-4100 ft (150-1250 m) >5000 ft (1500 m), nearly (based on typical (370-1340 m) (<300 m) (180-1130 m) all >4000 ft (1200 m) reported overburden
naturally occurring. Most of that which is not naturally occurring can be avoided through best-practice well completion. Two accounts of grey sediment temporally associated with HF activities apparently not investigated. of thousands of CSG wells. None of these three cases is inconsistent with historical, natural behaviour of groundwater in the region nor have they been tied to CSG operations. same aquifer so that drawdown (up to 200 ft or 60 m) causes wells to dry up. Methane contamination occurs but does not seem to be as widespread (report does not mention historical methane contamination). stemmed from CSG activities. But acknowledged soap contamination does show that drilling fluids can escape to the aquifer. Source: US EPA (2004), unless otherwise Table 4.2 Summary of producing US basins from which the EPA registered few or no resident complaints Piceance Basin Uinta Basin Northern Appalachian Basin Western Interior Coal Region Raton Basin Number of wells in operation (ca. year 2000) Not reported 1255 Not reported 377 Not reported Production (year 2000) 1.2 Bcf/y (34 million m3/y) 76 Bcf/y (2.2 billion m3/y) 1.41 Bcf/y (40 million m3/y) 6.5 Bcf/y (185 million m3/y) 31 Bcf/y (880 million m3/y) Size 7225 mi2 (19 billion m3) 14 450 mi2 (37 billion m3) 43 700 mi2 (113 billion m3) 87 000 mi2 (225 billion m3) 2200 mi2 (6 billion m3) Depth of wells Two-thirds of wells >5000 ft (1500 m), nearly all >4000 ft (1200 m) 1200-4400 ft (370-1340 m) Most <1000 ft (<300 m) 600-3700 ft (180-1130 m) 500-4100 ft (150-1250 m) (based on typical reported overburden
technical-report-number-04-lit-rev-hydraulic-fracture-growth.docx