دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

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.

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.

n: an acoustic logging method based on the fact that sound travels at different speeds through materials of different densities. The fact that sound travels faster through cement than through air can be used to determine whether the cement has bonded properly to the casing.

n: Reflect the quality of cement bond after cementing. Used to check cement job quality.

a sonic log that determines the top of the cement column and estimates the quality of the cement bond between the casing and the formation. Works on transmission of a sound wave and identifies areas that conduct the wave and those that do not (free pipe r

n: a type of acoustic log that records the travel time of sounds through objects, cement, or formation rocks. Often used to determine whether voids exist in the cement behind the casing in a well bore.

a sonic log measures the interval travel time (delta t) of compression sound waves moving through one foot of a formation (milliseconds/ft). If matrix velocity is known, porosity can be calculated since sound waves travel slower in porous media (travel sl

n: see acoustic well logging. sonic meter n: see ultrasonic mete,;

n: A type of acoustic log that displays traveltime of P-waves versus depth. Sonic logs are typically recorded by pulling a tool on a wireline up the wellbore. The tool emits a sound wave that travels from the source to the formation and back to a receiver.