ADVANCES IN WIRELINE
LOGGING TECHNOLOGY
BOTTOM LINE
Wireline logging tools have come a long way since the original Spontaneous Potential and Resistivity tools became
available decades ago. Today wireline logging tools provide basic reservoir data to operators and play a fundamental
role in determining stratigraphic correlations, lithology, wellbore conditions, fluid type and saturation, bound or moveable fluids, porosity, and permeability. Increasing accuracy of log data allow for more precise determination of reservoir
conditions, more realistic simulations, and they allow for more certainty when operational decisions must be made.
Thus selection of the appropriate wireline logging tools adds significant value for exploration, exploitation, and
workover tasks and can ultimately save money.
PROBLEM ADDRESSED
There are several new or improved well log technologies that can help operators to define
reservoir or rock/fluid parameters or borehole conditions. Borehole Imaging and Dipmeter
tools are useful in solving structural (including fracture), stratigraphic and reservoir condition problems. Nuclear Magnetic Resonance (NMR) is particularly useful in identification of
fluid types and water saturation. The Ultrasonic Scanning Tool is particularly useful for
cement evaluation and casing inspection. The Dual Spaced Chlorine Tool (DSCT) reads
behind pipe and is especially effective for determining water saturation and profile depletion through time-lapse monitoring. Geochemical Logging using the ECS Tool uses natural
Gamma-Ray signals to read behind pipe. It is particularly useful to determine quantified
lithology of the reservoir rock. The Cased Hole Formation Resistivity (CHFR) Tool is an
excellent choice for monitoring reservoir saturation changes with time. Because CHFR reads
beyond the mud invasion zone, results can be compared with open hole resistivity logs.
TECHNOLOGY OVERVIEW
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Wireline logging technology has been critical to the industry for decades. Today new or improved tools can provide
ever more accurate parameters for a wide variety of applications. Key new technologies discussed at the workshop
include:
Combined Borehole Imaging and Dipmeter tools are useful for solving three main categories of applications:
Based on a workshop sponsored by PTTC's Central Gulf Region
on September 13, 2001 in Shreveport, LA
SPEAKERS:
Imaging & Dipmeter
L. Mark Larsen, Schlumberger
Nuclear Magnetic Resonance
Dan Buller, Halliburton
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KEY WORDS:
Borehole Imaging
Cased Hole Formation
Resistivity (CHFR) Tool
Compensated Chlorine
Tool (DSCT)
Dipmeter
ESC Gamma-Ray Tool
Nuclear Magnetic
Resonance (NMR)
Ultrasonic Scanning Tool
Structural Problems. These tools are excellent to confirm
structural structural dip, define fault depth, strike and
locate downthrown fault block.
Stratigraphic Problems. Dipmeter and Borehole Imaging
tools have applications for determining the depositional
system and its orientation. They are also useful to identify both unconformities and sequence boundaries.
Reservoir Problems and Conditions. Thin beds can be
resolved, location (or planning for) sidewall cores, calibration to and from whole core, locating permeability
trends and barriers using Borehole Imaging and Dipmeter
tools. Fracture identification is a key feature that can be
addressed by the Borehole. These tools also provide
information about in-situ stress orientation based on
borehole geometry.
Compensated ChlorineTool
John S. David, Superior Well Services
The Dipmeter/Imaging tool selected depends, among other
things, on the type of mud used in the hole. For water-based
muds, the following tools will provide dip data only: High
Resolution Dipmeter Tool "HDT" and Stratigraphic High
Resolution Dipmeter Tool "SHDT". Dip data and Borehole
Images may be generated in water-based muds using the
Formation MicroScanner "FMS", the Formation
MicroImager "FMI", or the Resistivity At the Bit "RAB"
tools.
Geochemical Logging & Cased Hole Formation Resistivity
Rob North, Schlumberger
Dip data only may be generated in oil-based mud systems
using the SHDT with Scratcher Pads, or the Oil Base
Advanced Ultrasonic Scanning Tool
Gary James Frisch, Halliburton
Compensated Chlorine Tool
Ronald E. Bothner, Nuclear Reservoir Evaluation, Inc.
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Dipmeter Tool "OBDT". Dip and borehole image data are
collected using the Ultrasonic Borehole Imager "UBI", the
FMI, or the OBMI Oil Base Mud Imager.
Minimum and maximum borehole size limitations for the
various Formation MicroImager logs are as follows:
Ultrasonic Borehole Imager (UBI) 5.5"-12.875, Formation
Microscanner FMS-B, 4.5"-15", FMS-C 6.25"-21", and the
Formation MicroImager (FMI) is 6.25"-21". Each of these
tools has a maximum temperature range of 350° F.
Nuclear Magnetic Resonance (NMR) is a new borehole
measurement technique that allows a continuous log of
parameters such as permeability, volume of moveable fluids
and lithology-independent porosity. It is particularly useful
for determining fluid types; rock data is not recorded with
the NMR technology.
NMR logging trials have shown that three quantities are
measured with this new tool:
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Lithology-independent porosity: Because only oil and
water contain abundant hydrogen, the magnitude of the
NMR signal responds only to the liquid-filled porosity.
Permeability: The decay rate of the NMR signal is related
to the permeability of sandstones. NMR-derived permeability is typically an order of magnitude more accurate
than permeability derived from a porosity-permeability
relationship.
Initial water saturation: By comparing the fast relaxing
fraction of the NMR signal with the slow relaxing fraction, the amount of movable fluid in the pore space can
be determined. This is known as the Free Fluid Index
(FFI) of the formation and is an estimate of the initial
water saturation.
Values for these parameters can be determined accurately
for sandstone and do not need calibration of rock parameters (i.e., core is not needed). Such calibration, however, is
still required for carbonate rocks. Some applications for the
NMR tool include effective porosity (including vuggy vs.
matrix porosity), permeability, pore size distribution, producible fluids, predicted water cut, oil viscosity, and wettability.
It should be recognized that NMR has nothing to do with
radioactivity and the logging tool does not contain any
nuclear sources. NMR refers to the physical principal of resonance of nuclei in a magnetic field.
The Ultrasonic Scanning Tool has two main uses: cement
evaluation and for casing inspection.
For cement evaluation, it is recommended that one use a
cement interpretation logging tool combination that
includes a Cement Bond Log (CBL) and a single or multitransducer Ultrasonic tool. This combination of tools
should prove effective for evaluating conventional cement
slurries and foam and complex cement slurries. Cement
evaluation is strongly recommended for wells with multiple
pays. It will help determine zonal isolation and can there-
fore reduce unnecessary remedial work. This can lead to
operational cost savings.
Casing inspection using the Ultrasonic Scanning Tool
requires corrections for borehole eccentricity. The image
mode of this tool provides accurate internal wear assessment (up to 60 samples/ft) while the cased-hole mode (up
to 12 samples/ft) provides accurate casing thickness data.
The Dual Spaced Chlorine Tool (DSCT) reads behind pipe.
This tool is effective for determining current water saturation, gas/oil/water contacts, distinguishing between high
porosity gas zones and low permeability (tight) intervals,
profile depletion through time-lapse monitoring, and identifying formation water resistivity changes with respect to
well depth. An important feature of this tool is that it may
be used in shaley sands.
This tool is battery powered, has a maximum outside diameter of 1 11/16 inches over a 16 ft length, weighs 60 lbs and
is rated to 450° F and 22,000 psi. It is rated at 5 samples/ft
and 20 ft/min with a vertical resolution of 8 inches. The
recommended logging speed is, however, a function of formation porosity, salinity, and wellbore geometry.
Recommended conditions for optimal DSCT performance
include porosity greater than 15% and salinity greater than
25,000 ppm Cl. Well bore configuration recommendations
for high performance include boreholes of 12 ¼ inches or
less, casing sizes of 9 5/8 inches or less, absence of concentric casing strings, and a preference for liquid-filled annulus.
GEOCHEMICAL LOGGING AND CASED HOLE
RESISTIVITY TOOL
The ECS Geochemical Logging tool is the latest in a line of
Gamma-Ray measuring tools. It essentially captures from
behind pipe a Gamma-Ray Spectrum that is processed to
successively determine dry weight elements in the formation (rock) and ultimately dry weight lithologies (e.g., quantified clay, carbonate, anhydrite, etc). The tool is rated at a
logging speed of 1,800 ft/hr with a vertical resolution of 1.5
ft. It works in all borehole fluids. The tool has an outside
diameter of 5.0 inches over a 6.6 ft length. It is rated to 350°
F and 20,000 psi. It will operate in a minimum hole size of
6.0 inches.
The ECS and SpectroLith tool provide data to simplify log
interpretation and to allow more accurate petrophysical
interpretation, real time wellsite decisions such as drilling
and completion fluid compatability. Additional applications
for these tools include lithology determination for mechanical properties and frac design, enhanced seismic attribute
analysis, improved lithological models for reservoir simulation, and chemostratigraphy for improved correlation.
The Cased Hole Formation Resistivity (CHFR) Tool provides accurate resistivity measurements through casing. The
results have good repeatability in varied production environments. Therefore the tool provides an excellent basis for
monitoring reservoir saturation changes with time. CHFR
reads beyond mud invasion which effects nuclear tech-
niques. It thus allows direct comparison with open-hole
resistivity logs.
Major applications for this tool include primary resistivity
evaluation, locating bypassed pay, and monitoring reservoir
saturation changes.
CHFR specification includes a tool that is 3 3/8 inches in
diameter over a 43 ft length. It is rated to 300° F and 15,000
psi and can operate at a logging speed of 400 ft/hr. The tool
requires a casing outside diameter range of 4.5 to 9 5/8
inches. It can operate at any well deviation angle with
stand-offs, but only to 70° for 3 3/8 pipe. Vertical resolution
is 4 ft and depth of investigation into the formation is 7 to
32 ft
CONNECTIONS:
L. Mark Larsen
Schlumberger
330 Marshall St., Ste. 610
Shreveport, Louisiana 71101
Phone: (318) 222-0474 Fax: (318) 222-0810
Email: larsenm1@slb.com
Ronald E. Bothner
Nuclear Reservoir Evaluation, Inc.
2608 Southwest Drive
New Iberia, LA 70560
Phone: (337)364-3416 Fax: (337)367-5903
Email: ronnie@nregroup.com
John S. David
Superior Well Services
1207 Redwood Bough Lane
Houston, TX 77062
Phone: 1 (888) 485-5429 Fax: (281) 999-6505
Email: johnd37@swbell.net
Rob North
Schlumberger, DSC-ID
1325 S. Dairy Ashford Rd., Ste. 300
Houston, TX 77077
Phone: (281) 285-1912 Fax: (281) 2851927
Email: robnorth@houston.oilfield.slb.com
Dan Buller
Halliburton Energy Services
416 Travis St., Ste. 505
Shreveport, Louisiana 711015502
Phone: (318) 673-4415 Fax: (318) 220- 0234
Email: danbuller@halliburton.com
Gary James Frisch
Halliburton Energy Services
3000 N. Sam Houston Parkway
P.O. Box 60078
Houston, TX 77205
Phone: (281) 871-7215 Fax: (281) 871-7211
Email: gary.frisch@halliburton.com
For information on PTTC’s Central Gulf Region and its activities contact:
Director: Bob Baumann, Managing Director
Center for Energy Studies, Louisiana State University
One East Fraternity Circle
Baton Rouge, Louisiana 70803-0301
Phone: 225-578-4400 Fax: 225-578-4541
Email: rbaumann@lsu.edu
Disclaimer: No specific application of products or services is endorsed by PTTC. Reasonable steps are taken to ensure the reliability of
sources for information that PTTC disseminates; individuals and institutions are solely responsible for the consequences of its use.
The not-for-profit Petroleum Technology Transfer Council is funded primarily by the US Department of Energy’s Office of Fossil
Energy, with additional funding from universities, state geological surveys, several state governments, and industry donations.
Petroleum Technology Transfer Council, 2916 West T. C. Jester, Suite 103, Houston, TX 77018
toll-free 1-888-THE-PTTC; fax 713-688-0935; e-mail hq@pttc.org; web www.pttc.org