دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

the velocity of an imposed sound wave (acoustic velocity) through a rock times the density of the rock.

n: a record of the measurement of porosity, done by comparing depth to the time it takes for a sonic impulse to travel through a given length of formation. The rate of travel of the sound wave through a rock depends on the composition of the formation and the fluids it contains. Because the type of formation can be ascertained by other logs, and because sonic transit time varies with relative amounts of rock and fluid, porosity can usually be determined in this way.

n: A display of traveltime of acoustic waves versus depth in a well. The term is commonly used as a synonym for a sonic log. Some acoustic logs display velocity.

a sonic travel time record of a formation using a tool with an emitter and a detector. Measures porosity and is useful to compare to other porosity longs to estimate pore filling. Also used to generate rock strength evaluations.

n: a system consisting of a beacon positioned on the seafloor to transmit an acoustic signal, a set of three or four hydrophones mounted on the hull of a floating offshore drilling vessel to receive the signal, and a position display unit to track the relative positions of the rig and the drill site. Monitoring of the display unit aids in accurate positioning of the rig over the site.

n pl: the characteristic patterns for various degrees of cement bonding between the casing and the borehole that appear on an oscilloscope display when a sonic cement bond log is made.

velocity of an imposed sound wave through a rock.

n: the process of recording the acoustic characteristics of sub- surface formations, based on the time required for a sound wave to travel a specific distance through rock. The rate of travel depends on the composition of the formation, its porosity, and its fluid content. Also called sonic logging.