The Arbuckle aquifer is an extensive aquifer that contains mostly saline water and that immediately overlies Precambrian "basement" rocks throughout Kansas, except for major uplift areas where it has been removed by erosion. In the southeast part of the State, it is a major freshwater aquifer. The upper part of the Arbuckle contains significant oil and gas reservoirs in central and south-central Kansas. During the last 40 years, the Arbuckle also has become the major zone of fluid disposal in the State. Most of the fluids disposed into the Arbuckle were produced from oil and gas wells in other formations. In addition, some industrial waste is disposed of in the Arbuckle. However, in recent years, State water agencies have become increasingly concerned about injection of fluids into the subsurface and the effects of injection on the hydrologic systems involved. An investigation of the geohydrology of the Arbuckle aquifer and of the hydrologic aspects of fluid disposal into the Arbuckle was conducted by the U.S. Geological Survey, in cooperation with the Kansas Geological Survey, to evaluate these effects. Rocks of the Arbuckle aquifer are composed almost entirely of dolomite, except for a relatively thin basal sand. The hydrologic characteristics of the dolomite have been affected by uplift, fracturing, and dissolution. Major regional karst-type cavernous zones have developed throughout the State with probably more pronounced development in the uplift areas. Thickness of the Arbuckle ranges from about 200 to 1,400 feet and increases in thickness to the south. Depths to the top of the Arbuckle range from about 500 feet in the southeast to about 7,500 feet in the southwest. Hydraulic characteristics obtained from drill-stem tests, injection tests, and numerical modeling have indicated a range of permeability in the Arbuckle from 1 millidarcy to 30 darcys. Permeability in the basin areas probably is much smaller than in the uplift areas. Analysis of injection tests indicated that average permeability in the basin areas probably is in the 50-to 300-millidarcy range. Analyses of 76 geophysical logs indicate an average porosity of about 12 percent. An evaluation of the geohydrology of the Arbuckle shows that it is a large regional-flow system that is in hydraulic connection with several other major aquifers. The Arbuckle is in contact with overlying rocks of different hydraulic characteristics and hydraulic heads; this results in potential for transfer of fluids between the units. Groundwater flow within the Arbuckle is principally from the west-northwest to the eastsoutheast, although there are areas where the flow is mainly to the east or west. Groundwater flow in the Arbuckle enters the State from Missouri and continues to the west-northwest until it contacts a more saline groundwater flow system, where it then moves upward and to the south and north. Flow of relatively fresher ground water enters the Salina basin from the northwest and continues to the south-southeast through the Sedgwick basin. Some of this ground ...

No abstract

No abstract

No abstract

No abstract