The sonic or acoustic log measures the travel time of an elastic wave through the formation. This information can also be used to derive the velocity of elastic waves through the formation. Its main use is to provide information to support and calibrate seismic data and to derive the porosity of a formation.
What is Sonic response?
A series of performances that explore the sounds – and silence – of a now-quiet campus.
What is slowness in sonic logging?
ADVERTISEMENT. A sonic log is an acoustic log that emits sound waves which start at the source, travel through the formation, and return back to the receiver. The travel time from the source to the receiver is called slowness and as a result sonic logs are sometimes referred to as sonic slowness logs.
What is acoustic porosity?
Acoustic porosity is a measure of the primary or intergranular (matrix) porosity.
What is Dipole Sonic?
A sonic array tool in which sources are dipoles as opposed to radially symmetric monopoles, so that it generates both P- and S-waves in formations. … The dipole sonic imager (DSI) is a multiconfigurable tool that can emulate a BHC sonic, a standard monopole array tool, or an array dipole tool.
What is compressional slowness?
A technique for recording the formation compressional slowness based on the transit time between transmitter and receiver. … The time between emission and reception is measured for each receiver, and subtracted to give the traveltime in the interval between the two receivers.
What is slowness and velocity?
Slowness (s) is a quantity introduced in Seismology which is the reciprocal of velocity. Thus travel time of a wave is the distance that the wave travels times the slowness of the medium ( in seismology, it refers to different layers of Earth exhibiting different densities) Thus, Slowness = 1/Velocity.
How do sonic logs work?
Sonic logs rely on the properties inherent in Snell’s Law to propagate sound from a logging tool through the rock to receivers located on the same logging tool. Sonic logs require a fluid filled borehole to operate properly. Modern logs can make most measurements in both open and cased holes.
What is interval transit time?
1. n. [Geophysics] 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.
What is Rhob log?
The density log usually labelled ‘RHOB’ measures the density of the borehole and the rocks penetrated by the drill bit. The unit for density is gram per cubic centimetre. The logs (sonic and density) measurements are usually made every 6 in. down hole, but must be aligned to be ‘on-depth’ with each other.
What is electric logging?
Electric logging consists of lowering a device used to measure the electric resistance of the rock layers in the downhole portion of the well. This is achieved by running an electric current through the rock formation and measuring the electrical resistance that the current encounters along its way.
What is FMI log?
A downhole micro electrical resistivity technique first used for oil and gas wells in the late 1980’s.
What does acoustic impedance depend on?
It describes how much resistance an ultrasound beam encounters as it passes through a tissue. Acoustic impedance depends on: the density of the tissue (d, in kg/m3) the speed of the sound wave (c, in m/s)
How do you read a neutron log?
How do you read neutron density logs?
What is DSI tool?
The Dipole Sonic Imager Tool (DSI-2) combines high-speed telemetry with simultaneous, 12-bit dynamic range digitization of an eight-receiver array.
What is a sonic scanner?
Sonic Scanner acoustic scanning platform accurately measures elastic properties axially, radially, and azimuthally to support geomechanical, geophysical, fractures, and petrophysical modeling.
What is shear wave velocity?
4.8 Shear wave velocity and shear modulus at small strain Shear wave velocity (Vs) induced shear modulus known as a key geotechnical property corresponded to small strain which is important in earthquake investigations.
What is the ray parameter?
Definition: The ray parameter is the geometric property of a seismic ray that remains constant throughout its path. It is invariant in transmission, reflection, refraction and transformation. It is equal to r sin i / v.
What is slowness curve?
The slowness curves were defined for a fixed frequency by monitoring the slowness of the pole of the HA as a function of the angle of propagation. … … Under a metallic grating however, the wave characteristics are dispersive.
What is a word for slowness?
In this page you can discover 26 synonyms, antonyms, idiomatic expressions, and related words for slowness, like: drowsiness, inactivity, feebleness, impotence, indifference, stupidity, weakness, deliberation, deliberateness, unhurriedness and retardation.
How do neutron logs work?
The neutron log is sensitive mainly to the amount of hydrogen atoms in a formation. … The tool operates by bombarding the formation with high energy neutrons. These neutrons undergo scattering in the formation, losing energy and producing high energy gamma rays.
What is well log data?
Well logs are records of petro-physical data acquired along a borehole, providing direct information about what is in the subsurface. The data collected by logging wells can have significant economic consequences, due to the costs inherent to drilling wells, and the potential return of oil deposits.
What do resistivity logs measure?
Resistivity logging is a method of well logging that works by characterizing the rock or sediment in a borehole by measuring its electrical resistivity. Resistivity is a fundamental material property which represents how strongly a material opposes the flow of electric current.
What is transit time in geophysics?
1. n. [Geophysics] The duration of time for a P-wave to travel one foot, typically displayed on an acoustic log. The unit of microseconds per foot (or meter) is called the slowness, which is the inverse of velocity.
