Engineering Methods

Additional Information

Borehole Logging

Borehole geophysical logging includes the measurement of various chemical and physical characteristics of materials and fluids in and around a borehole. These important tools have a key advantage over surface methods in that measurements of the physical properties of soil and rock are recorded and analyzed underground at their location from wells or test holes . Down-hole probes, or logging sondes, are used to acquire continuous vertical data directly from or into the materials. The probes measure a variety of electrical, nuclear, and acoustical properties of the subsurface formations. These data are used to characterize the formations (e.g. lithology, thickness, depth) and quantify hydrogeological properties (e.g. porosity and permeability). When incorporated with surficial geophysics, a more comprehensive, accurate and definitive result is achieved during geotechnical engineering, groundwater and environmental studies. 

Nuclear Magnetic Resonance Permeability Log

Porosity, permeability, and sonic logs from a monitoring well in the Floridian Aquifer, South Florida. The lithology log shows a high correlation between lithology, pore type, and permeability

Typically, multiple logs are acquired and grouped for analysis as a suite of geophysical data profiles to aid with hole to hole correlation and estimation of such properties as density, porosity, and composition ratios. Common applications are groundwater and environmental investigations to obtain information regarding well construction, rock lithology and fractures, permeability, porosity, and water quality. Borehole logging is a frequently applied, cost effective method, for obtaining data needed for several phases of hydro-geologic, geotechnical and environmental investigations.