Editing Well logging (section)

{{short description|Detailed record of borehole contents}}
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{{Well logging}}

'''Well logging''', also known as '''borehole logging''' is the practice of making a detailed record (a ''well log'') of the [[Formation (stratigraphy)|geologic formations]] penetrated by a [[borehole]].  The log may be based either on visual inspection of samples brought to the surface (''geological'' logs) or on physical measurements made by instruments lowered into the hole (''geophysical'' logs).  Some types of geophysical well logs can be done during any phase of a well's history: drilling, completing, producing, or abandoning. Well logging is performed in boreholes drilled for the [[hydrocarbon exploration|oil and gas]], [[groundwater]], [[Mineral exploration|mineral]] and [[Geothermal exploration|geothermal]] exploration, as well as part of environmental, scientific and [[geotechnical]] studies.