Hydrogeologic testing of the E.J. Kubat borehole, San Juan County, Utah: utilization of a high pressure instrumented flow control system

The E.J. Kubat borehole, located in San Juan County, Utah, in the SW 1/4, Section 23, T37S, R19E, was drilled in 1958 as a petroleum exploration (wildcat) well. Drilling records and geophysical logs were examined as a part of the Paradox Basin Project, a feasibility and siting study for a high-level nuclear waste repository to be located in bedded salt deposits in the Utah portion of the Paradox Basin. This project is part of the Department of Energy National Waste Terminal Storage Program, and is being conducted by Woodward-Clyde Consultants under subcontract to Battelle Memorial Institute, Office of Nuclear Waste Isolation. The geophysical logs of the Kubat and nearby wells showed that salt cycles potentially suitable as a possible repository horizon existed within the Pennsylvanian-age Paradox Formation in the area. Thus, it was decided to re-enter the well and extend it deeper into the Mississippian Leadville Limestone, the major water-bearing formation underlying the repository horizon. A series of hydrogeologic tests was conducted to evaluate hydrogeologic properties of the Leadville Limestone. These tests provided data on potentiometric level, transmissivity and permeability of the test interval. Although testing of relatively highly permeable formations is common, obtaining reliable data from formations of low permeability is more difficult, and is a special aspect of the paradox Basin Project