Characterization of a Crystalline-Bedrock Aquifer Using Borehole Geophysics, Marietta, Cobb County, Georgia

Abstract

Borehole geophysical techniques were used to characterize a crystalline-bedrock aquifer at the U.S. Air Force Plant 6 in Marietta, Georgia. An integrated suite of geophysical logs was collected from 400- to 600-foot deep wells, which are steel cased to the top of bedrock with the remainder of the borehole open. The geophysical logs include caliper, fluid resistivity, temperature, natural gamma, electromagnetic induction, spontaneous potential, single-point resistance, digital optical and acoustic televiewer, and deviation heat-pulse flowmeter. Fluid resistivity, temperature, and flowmeter logs were used to delineate flow zones. Caliper and acoustic- and optical-televiewer logs were used to determine fracture and foliation character and orientation.