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Lecture items
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Logging Up?
Wireline Log Services.
What Logs can measure?
The role of the Well Log Analyst
Creating the Well Log “Logging Operation”
Sound waves through
open hole logging
operation.
LWD
&
MWD
Logging Up
To log the well, drilling must be stopped and the drill
string must be removed from the borehole. Typically, the
winch lowers the wireline cable and sonde to the bottom
of the borehole. When the sonde is on the bottom, the
winch slowly rises it up to the surface. When it moves up
through the borehole, the sonde takes formation
measurements. This is called "logging up. In some cases,
measurements may be taken as the sonde is lowered into
the borehole .The electrical cable carries power to the
sonde .Measurements are not stored in the sonde.
Instead, formation measurements are transmitted
uphole through the cable to the logging unit for
processing.
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Wireline Log Services
 There are several wireline logging services,
some of which are similar to LWD, such as
(gamma ray( GR ,)resistivity, and nuclear(
(porosity and bulk density). Other services
that wireline log measurements have, not
offered by LWD as Seismic. This service uses
a device, such as an air gun, at the surface to
produce sound waves in the formation. A
geophone is lowered into the borehole. As it is
rises up to the surface, the geophone detects
the sound waves and converts them into an
electric voltage. Logs produced by this service
are used to determine the lithology and
porosity of the formation
Formation testing and sampling
 The wireline tool has the capability of taking samples
of the formation. There are two methods for taking
samples .In both methods, the samples are brought to
the surface and analyzed to accurately determine the
properties of the formation .
i-Side wall coring - A hollow cylinder is shot into
the formation and pulled out to retrieve a core
sample .
ii-Fluid sampling - The sonde has pads attached
to legs. The legs are extended so that the pads are
forced against the walls of the borehole. This allows
formation fluid to flow into one or more tanks inside
the sonde .
Cased-hole logging 
Wireline logging can be done in cased 
holes. Casing is thin-walled, steel pipe
that is run in the hole to prevent
borehole collapse as drilling progresses.
The casing is cemented to the borehole
wall.
Wireline has developed instruments that 
can take formation measurements
without interference from the casing and
cement
Creating the Well Log “Logging Operation”
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Wireline Logging
Basically, the equipment needed for wireline logging
consists of the following:
Up-hole instruments (Logging Unit and Rig)
Down- hole instruments (Sondes and cables)A logging
unit and an instrument for taking measurements. For
land rigs, the unit is mounted on a truck. The unit has
a winch and an electrical wireline cable.
The Downhole logging instrument, called a sonde, is
attached to the end of the cable. The unit also includes
equipment to power the sonde and to make a
permanent record of the log.
Recording the Well Log
Inside a
Modern
Logging
Unit