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.

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: 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

an acoustic log that helps determine if fractures are present.

n: The amount of time for a wave to travel a certain distance, proportional to the reciprocal of velocity, typically measured in microseconds per foot by an acoustic log and symbolized by t or DT. P-wave interval transit times for common sedimentary rock typ

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.

n: the recording of information about subsurface geologic formations, including records kept by the driller and records of mud and cutting analyses, core analysis, drill stem tests, and electric, acoustic, and radioactivity procedures. See acoustic log, core analysis, drillers log, drill stem test, electric well log, mud analysis, and radioactivity log.

n: Electric logs are run on a wire line to obtain information concerning the porosity,permeability,fluids content of the formations drilled and other information .The drilling-fluid characteristics may need to be altered to obtain good logs.

n: measures the time needed for a sound pulse generated at the surface to reach successive selected depths in the borehole. Used to correct problems in downhole acoustic logs caused by filtrate invasion of the formation and borehole irregularities. Also used to calibrate depths on seismic sections.

n: the recording of subsurface characteristics by wire line (actually conductor line) tools. Wireline well logs include acoustic logs, caliper logs, radioactivity logs, and resistivity logs.

A continuous measurement of formation properties with electrically powered instruments to infer properties and make decisions about drilling and production operations. The record of the measurements, typically a long strip of paper, is also called a log.