Date of Award
Master of Science (MS)
Seismographic petroleum exploration throughout North Dakota has generated concern over the effects of blasting on groundwater supplies and wells. A preliminary investigation revealed complaints alleging declining productivity and decreased water quality in regions where coal aquifers are extensively used. Unplugged shotholes were frequently cited as a source of problems.
Experimental results indicate that changes due to blasting occur within long term physical the aquifers rather than in specific water wells. Pumping tests conducted in a sand and coal aquifer system showed no apparent physical effects when shots were detonated one quarter mile away from the pumping wells. Shots 500 feet distant resulted in no permanent effects. Shots 100 feet or closer increased the yield from wells finished in the sand aquifer and decreased the yield from the coal aquifer. Fracturing of the poorly indurated sandstone aquifer is suggested as a mechanism for the increase. Collapse of fractures is suggested as the failure mechanism in the coal aquifer. Well casings remained intact after 25 pound charges were detonated as close as 10 feet from a well screen. Currently available methods for evaluating pump test data do not adequately were also provided. Rick Nelson, Environmental Engineer, served as the Health Department liasion. Rod Reetz and Ken Kary of the North Dakota State Department of Health Laboratories were especially helpful in expediting the sample analyses in the face of staggering backlogs of samples from other sources.
The North American Coal Corporation deserves special consideration for their willingness to let us use their land holdings as an experimental site. Site consolidation made the logistics much more manageable than they would have been with multiple sites. Jim Brown, Director of Environmental· Control, was instrumental in obtaining permission within the company and Terry Zich, Hydrologist, served as a cooperative and helpful liaison;
Keith Whittemore of the Amoco Oil Company, and P. D. O'Brien of Grant Geophysical Inc., and J. R. Freeman travelled to Grand Forks in midwinter to discuss the project and to offer assistance. Jim Reil of Vibra-Tech Engineers donated the use of a portable seismograph and analyzed the data collected.
My wife and daughters have been especially tolerant of my absences during the fieldwork and preparation of this thesis. Without their cooperation, this endeavor would not have been possible. address coal fracture permeability. Consequently, values for transmissivity, storativity, and specific yield were unobtainable.
During the pumping tests, no significant long term chemical or mineralogical equilibrium changes were observed which could be attributed to the blasting. Water quality changes resulted from pumping during the early time segments of the pump tests. Immediately following a shot 100 feet from a pumping well finished in coal, a short term increase in most chemical parameters was noted. Shots farther away had no apparent effect on chemical quality. Well owners and explorers are advised to collect water quality and pumping drawdown data before any exploration is conducted. The relative productivity of any well can be determined by pumping the well and noting the drawdown with time. If done prior to exploration, these measures provide an excellent basis for evaluation of the effects of blasting.
Beaver, Frank W. Jr. P. E., "The effects of seismic blasting on shallow water wells and aquifers in western North Dakota" (1984). Theses and Dissertations. 16.