Wednesday, December 5, 2007 : 10:40 a.m.

Integrated Flow and Fluid-Property Logging for Well Evaluation and Flow-Zone Characterization in Carbonate-Bedrock Aquifers

John H. Williams, USGS

Test, monitoring, and production wells completed in carbonate-bedrock aquifers commonly are open to multiple flow zones.  Characterization of the transmissivity, hydraulic head, and water quality of the discrete flow zones penetrated by the wells is important in both regional and site-specific aquifer investigations.  Integrated flow and fluid-property logging has proven to be an efficient method for flow-zone characterization in a range of well conditions and aquifer settings in carbonate bedrock.

 

Flow logs of the multi-zone wells were collected under steady-state ambient and pumped conditions with heat-pulse and electromagnetic flowmeters.  The combined measurement range of the high-resolution flowmeters configured with fully-fitted diverters spanned flows encountered under ambient and low-rate pumped conditions. Flows under high-rate pumped conditions in large-diameter test and production wells were measured with the electromagnetic flowmeter configured without a diverter or with an underfit diverter.  Wellbore-diameter, acoustic- and optical-image, and fluid-property logs served as guides for the collection and interpretation of the flow logs.  Model analysis of the ambient and pumped flow logs along with drawdown data provided estimates of the transmissivity and hydraulic head of the flow zones. 

 

Fluid-property logs collected under the same ambient and pumped conditions were interpreted along with the flow logs to determine the quality of water from the flow zones.  Depth-dependent samples for water quality and specific-ion logs from newly developed multi-parameter probes supplemented traditional fluid resistivity and temperature logs.

 

Integrated flow and fluid-property logging for well evaluation and flow-zone characterization in the Paleozoic (New York), Floridan (Florida and South Carolina), and Edwards (Texas) carbonate-bedrock aquifers will be presented.  Case studies will demonstrate applications in test wells for hydraulic characterization and design of discrete-zone head and water-quality monitoring installations, and applications in monitoring and production wells for saltwater intrusion and other non-point contamination assessments.

 

John H. Williams, USGS John H. Williams has a MS in Geology from Penn State University and currently is the Ground-Water Specialist for the U. S. Geological Survey Water Science Center in New York. He is an integral part of a Survey-wide training and technology transfer program in borehole geophysics. John also has provided technical assistance to the U. S. Environmental Protection Agency, Army Corp of Engineers, Nuclear Regulatory Commission, and State cooperators on borehole-geophysical applications in a wide range of ground-water investigations in fractured bedrock.


2007 NGWA Ground Water Expo and Annual Meeting