Wireline logging is an industry specific term used commonly in the oil and gas industry, which involves lowering a logging device or “tool string” attached to a wireline cable into a borehole or oil well which measures the properties of the rock and fluids within the formation. This technique dates to the early 1920’s when Conrad and Marcel Schlumberger, ran what is considered to be the very first wireline log at the Pechelbronn Oil Company oil field in France.