Well Logging - part 1 (The Bore Hole Image)

Introduction and Principles
WELL LOG  (The Bore Hole Image)

ØWell log is a continuous record of measurements made in bore hole, respond to variation in some physical properties of rocks through which the bore hole is  drilled. or

ØThe well log is a record of the  voyage of  measuring instrument 

into a well bore.

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ØThe instrument is called a Logging Tool.

ØTraditionally Logs are display on grid papers shown in figure below.

Now a days the log may be taken as films, images, and in digital format

***Grid paper of a log***

Wire-line Logging

—Basically, the equipment needed for wire-line logging consists of the following:

—1-Up-hole instruments (Logging Unit and Rig)

—2-Down- hole instruments (sondes and cables) .

—For land rigs, the unit is mounted on a truck, and has a winch with electrical wire-line cable.

Creating the Well Log

*The down hole logging instrument called  Sonde is  attached to the end of t he cable.

*The unit also includes equipment to power the sondes  and to make a permanent record of the log

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