Home > Terms > English (EN) > sonic measurement

sonic measurement

A technique for recording the formation compressional slowness based on the transit time between transmitter and receiver. In the most basic wireline sonic measurement, an acoustic transducer emits a sonic signal, of between about 10 and 30 kHz, which is detected at two receivers farther up the hole. The time between emission and reception is measured for each receiver, and subtracted to give the traveltime in the interval between the two receivers. If the receivers are two feet apart, then this time is divided by two to give the interval transit time, or slowness, of the formation. This type of measurement is also known as first motion detection.

This technique works because the first arrival at the receiver is a wave that has traveled from the transmitter to the borehole wall, where it has generated a compressional wave in the formation. Some of this wave is critically refracted up the borehole wall, generating head waves in the borehole fluid as it progresses. Some of these strike the receiver, arriving in most cases well before any signal traveling directly through the mud. Furthermore, if the logging tool is parallel to the borehole wall, the traveltime in the mud is cancelled by taking the difference between the traveltime to the two receivers. Problems of irregular hole or a tilted tool are avoided by using borehole compensation.

The depth of investigation depends on the slowness, the transmitter-to-receiver spacing and the presence or absence of an altered zone. It is generally within the invaded zone, and of the order of several inches.

0
Collect to Blossary

Member comments

You have to log in to post to discussions.

Terms in the News

Billy Morgan

Sports; Snowboarding

The British snowboarder Billy Morgan has landed the sport’s first ever 1800 quadruple cork. The rider, who represented Great Britain in the 2014 Winter Olympics in Sochi, was in Livigno, Italy, when he achieved the man-oeuvre. It involves flipping four times, while body also spins with five complete rotations on a sideways or downward-facing axis. The trick ...

Marzieh Afkham

Broadcasting & receiving; News

Marzieh Afkham, who is the country’s first foreign ministry spokeswoman, will head a mission in east Asia, the state news agency reported. It is not clear to which country she will be posted as her appointment has yet to be announced officially. Afkham will only be the second female ambassador Iran has had. Under the last shah’s rule, Mehrangiz Dolatshahi, a ...

Weekly Packet

Language; Online services; Slang; Internet

Weekly Packet or "Paquete Semanal" as it is known in Cuba is a term used by Cubans to describe the information that is gathered from the internet outside of Cuba and saved onto hard drives to be transported into Cuba itself. Weekly Packets are then sold to Cuban's without internet access, allowing them to obtain information just days - and sometimes hours - after it ...

Asian Infrastructure Investment Bank (AIIB)

Banking; Investment banking

The Asian Infrastructure Investment Bank (AIIB) is an international financial institution established to address the need in Asia for infrastructure development. According to the Asian Development Bank, Asia needs $800 billion each year for roads, ports, power plants or other infrastructure projects before 2020. Originally proposed by China in 2013, a signing ...

Spartan

Online services; Internet

Spartan is the codename given to the new Microsoft Windows 10 browser that will replace Microsoft Windows Internet Explorer. The new browser will be built from the ground up and disregard any code from the IE platform. It has a new rendering engine that is built to be compatible with how the web is written today. The name Spartan is named after the ...

Featured Terms

DominikB
  • 0

    Terms

  • 0

    Blossaries

  • 2

    Followers

Industry/Domain: Entertainment Category: Movies

Child's Pose

The 2013 Romanian drama film Child's Pose (Romanian: Poziția copilului) is directed by Călin Peter Netzer. The film premiered in competition at the ...