MIT

MULTI FINGER IMAGING TOOL

User Guide

V1.0 May 2004

WARNING! Before using any Sondex equipment, refer to the operational and maintenance manuals for
full safety information.

Copyright © Sondex 2004 All Rights Reserved.

ΠFORD LANE ΠBRAMSHILL ΠHOOK ΠHAMPSHIRE ΠRG27 0RH ΠUK Tel +44 (0) 118 932 6755 Fax +44 (0) 118 932 6704
www.sondex.com Πemail sondex@sondex.co.uk
 Multi Finger Imaging Tool MIT
_________________________________________________________________
Functional Description
The prime use for the Multi Finger Imaging Tool is to record data to enable the client to maximize production or
recovery from the field, either through appropriate remedial work on a well or by providing information to optimally
manage the field.

During the course of producing a field problems may show up, often as the wells get older. MIT information will
help towards correcting these problems. Some examples of need for downhole knowledge of the tubulars are
illustrated below:
MIT Example Problems

A. CORROSION B.

Tubing
SCALE BUILDUP
Wall IS CHOKING
FLOW
HOLE IN
TUBING

RING DAM AGE DUE

C. TO TURBULENCE
CAUSED BY
D. M AP
PERFORATIONS
LANDING NIPPLE

LOW ORDER
LANDING DETONATIONS
NIPPLE

BLOCKED
PERFORATIONS

M ILLING OR
DRILLING
E. LANDING F. DAM AGE
G.
NIPPLE

SEAL THINNING OF THE CRUSHED

BORE CONFIRM ATION OF WALL HAS REDUCED TUBULAR
DIM ENSIONS OF TUBULAR BURST
PREVENTING
DOWNHOLE PRESSURE
WELL ENTRY
COMPLETION
ITEM

A: Corrosion Problems If the well fluids and gases are corrosive, corrosion damage can occur. In
extreme cases this can result in holes in the tubulars. If the tubing is plastic
coated to combat corrosion and the coating is breached, corrosion will occur.
B: Scale Build Up Changes in pressure, temperature and mixing of different fluids can cause
chemical precipitation on the well tubulars. This can restrict flow and also prevent
the locating of downhole flow control equipment.
C: Erosion Damage due to If there is extreme turbulence (typically in high rate wells) it is possible to get
well flow erosion damage. This occurs when the internal diameter changes. It is also
possible to damage tubulars by erosion during fracture treatments.
D: Mapping Perforations The presence of perforations may be confirmed and also if the charges have not
perforated the casing or the perforations have become blocked up.
E: Confirmation of Well The size and condition of downhole flow control items (the ‘jewelry’) can be
Completion Items. confirmed. For example the sealing bore of a landing nipple may be damaged.
F: Milling / Drilling If a well has taken a long time to drill, is corkscrewed or has had milling
Damage operations the wall thickness may have been reduced. This can result in a
reduction in the burst pressure of the casing which will compromise well integrity.
G: Crushed or Damaged If too much weight has been put on the tubulars or damage has occurred running
Tubulars the completion it is possible to have buckling or crushed tubulars. This can
prevent the running of downhole completion items or tools. Tubulars can also be
damaged or even sheared by tectonic movement as reservoirs deplete.
__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 2 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________

Example of Holes in Tubing

One of the primary reasons for running an MIT tool is

to evaluate the condition of the tubing. MIT tools are
run routinely in wells with known corrosion problems
and in old wells. The example on the right shows both
corrosion and holes in tubing. MITview has been used
to create a 3D image of the ID of the tubing where
different radii are mapped to different colours. On the
left we can see fingers protuding through a simulated
outside diameter. The MIT tool also contains an on-
board inclinometer which is used to re-orientate the
data such that in a deviated well the high side is at the
top. In this example we can see that the damage is
mainly on the lower side of the tubing which could be a
result of water travelling or re-circulating on the low
side. We can also assess the damage and remaining
wall thickness by creating a cross section view.

SPECIFICATIONS

The MIT tools are available in 24, 40, 60 and 80 finger versions. The choice of tool is dictated by the tubing size.
In general the largest tool which can go down the well safely is used. In some cases, such as to pass through
tubing and log the casing underneath, the tool measurement range can be extended (at the expense of resolution
and circumferential spacing) by fitting extended length fingers. The tool measures tubular internal diameter using
spring loaded fingers and has an onboard inclinometer which is used to denote well deviation and to re-orientate
the data to match the orientation of the well tubulars.

__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 3 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________

Tool Type Tool OD Range, inches Accuracy, Resolution,

inches inches
24 Finger MIT Standard Fingers 1.69” 1.75” to 4.50” +/- 0.030” 0.003”

24 Finger MIT Extended Fingers 1.69” 1.75” to 7.00” +/- 0.030” 0.007”
40 Finger MIT Standard Fingers 2.75” 3.00” to 7.00” +/- 0.030” 0.005”
40 Finger MIT Extended Fingers Under Development
60 Finger MIT Standard Fingers 4.00” 4.50” to 9.625” +/- 0.030” 0.006”
60 Finger MIT Extended Fingers 4.00” 4.50” to 13.375” +/- 0.030” 0.011”
80 Finger Tool Standard Fingers 8.00” 8.50” to 14.00” +/- 0.030” 0.007”
80 Finger MIT Extended Fingers 8.00” 8.50” to 20.00” +/- 0.030” 0.014”

Notes:

• The tools have an on-board inclinometer with deviation accuracy + / - 5 degrees (between 5 and 70
degrees from vertical).
• The inclinometer also serves as the rotation sensor with accuracy + / - 5 degrees.
• The upper range of the tool is only attainable if the tool is perfectly centralized.
• Extended fingers lower the radial resolution of the tool.
• Extended fingers increase the circumferential spacing (i.e. increases the gap) between the fingers.

Running the tool

The tools are pre-job calibrated at surface using a multi-size calibration ring. The tool is closed and then run in the
well to the bottom of the logging interval, the fingers are motored out and the tool is logged out of the hole at a
recommended 30 to 45 ft/min (10-15 m/min). At the top of the logging interval the fingers are closed and the tool
is either run back in hole for another log or pulled out of hole. At surface a post job calibration is performed.

__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 4 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________
Make up of MIT Logging Strings

The make up of the toolstring is dependent upon the type of tool used and whether the tool is run for surface
readout operations or memory readout operations.

Surface Readout Logging String Components

SURFACE READOUT MIT STRINGS

PSJ
Swivel
Joint

Conducting
Conducting Conducting Sinker Bar
Sinker Bar Sinker Bar

PKJ
Conducting
PKJ PKJ Knuckle
Conducting Conducting Joints
Knuckle Knuckle
Joints Joints
Roller Centraliser
Recommended
Roller Centraliser Additional
Roller Centraliser
MIT Electronics
and Motor

MIT Electronics MIT Electronics

MIT Fingers MIT Fingers
MIT Fingers
MIT Motor MIT Motor
Integral Roller Centraliser
Recommended
Roller Centraliser Additional
Roller Centraliser Roller Centraliser

Bullnose Bullnose Bullnose

24 Finger MIT 40 and 60 Finger MIT 80 Finger MIT

Weight Bars A conducting weight bar is used at the top of the string to carry the tool down the well.
An optional swivel joint may be used.
Knuckle Joints Tandem knuckle joints are used to assist with centralisation by de-coupling the weight of
the weight bars from the MIT tool.
MIT and Each tool has beryllium copper fingers with tungsten carbide coated tips. The finger
Finger Section design incorporates a leaf type spring to apply the finger pressure. The fingers are
opened and closed by motor on command from surface.
24 Finger Tools: The tool has a motor at the bottom of the tool to open and close the
fingers. There are no integral centralisers.
40 and 60 Finger Tools: The tool has a motor at the top of the tool to open and close
the fingers. There are integral centralisers.
80 Finger Tools: The tool has a motor at the bottom of the tool to open and close the
fingers. There are no integral centralisers.
Additional 24 Finger Tools: Additional centralisers are required top and bottom.
Roller 40 and 60 Finger Tools: The tool has integral centralisers but we recommend that if
Centralisers the well is over 60 degrees deviation that additional centralisers are run.
80 Finger Tools: Additional centralisers are required top and bottom.
Bullnose A bullnose is required for the bottom of the string. The next generation Ultrawire MIT
tools can be run with additional tools attached to the bottom of the string.
.
Memory Readout Logging String Components
Memory Readout operations require the addition of a battery powered memory recorder and a separate battery to
supply power for opening and closing the tool.
__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 5 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________

M EM O R Y READ O U T M IT STR ING S

W eight Bars go H ere W eight Bars go H ere
Slickline Knuckle Slickline Knuckle
Joint Joint
Battery for Battery for
M em ory Recorder M em ory Recorder

64 M egabyte 64 M egabyte
M em ory Recorder M em ory Recorder

Tandem Conducting Tandem Conducting

Knuckle Joints Knuckle Joints

Recom m ended
Roller Centraliser Additional
Roller Centraliser
Integral
Roller Centraliser
M IT Electronics M IT Electronics
M IT Fingers M IT Fingers
M IT M otor M IT M otor
Integral
Battery for M IT Roller Centraliser
M otor Battery for M IT
M otor
Recom m ended
Roller Centraliser
Additional
Roller Centraliser
Bullnose
Bullnose

24 Finger M IT 40 and 60 Finger M IT

Weight Bars Weight Bars are used at the top of the string to carry the tool down the well
Memory A lithium battery powered EEPROM high capacity memory recorder is used to record data
Recorder and from the tool. This is programmed before the job and the data is downloaded after the
Battery job. The fingers are opened and closed on command from the memory.
Knuckle Joints Tandem knuckle joints are used to assist with centralisation by de-coupling the weight of
the weight bars, memory section and motor battery from the MIT tool.
MIT and Each tool has beryllium copper fingers with tungsten carbide coated tips. The finger
Finger Section design incorporates a leaf type spring to apply the finger pressure.
24 Finger Tools: The tool has a motor at the bottom of the tool to open and close the
fingers. There are no integral centralisers.
40 and 60 Finger Tools: The tool has a motor at the top of the tool to open and close
the fingers. There are integral centralisers.
80 Finger Tools: The tool has a motor at the bottom of the tool to open and close the
fingers. There are no integral centralisers.
Motor Battery A high current Lithium battery is used to power the tool open and closed.
Additional 24 Finger Tools: Additional centralisers are required top and bottom.
Roller 40 and 60 Finger Tools: The tool has integral centralisers but we recommend that if
Centralisers the well is over 60 degrees deviation that additional centralisers are run.
80 Finger Tools: Additional centralisers are required top and bottom.
Bullnose A bullnose is required for the bottom of the string. The next generation MIT tools can be
run with additional tools attached to the bottom of the string.

Key Points

• The MIT can be run in memory or surface readout mode. In memory mode a battery powered high capacity
memory recorder is used and a separate high current battery to power the motor.
• Currently (May 2004) the surface readout and memory tools are incompatible. Ultrawire tools are due out in
2005.
• The tool size is dependent upon the number of fingers.
• The largest tool that can be run in the completion safely should be used so as to maximize coverage.
• The fingers are opened and closed using an on-board motor
__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 6 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________
• The tool can be opened and closed as many times as required within one run.
• Multiple tubing sizes can be logged with one tool.

Typical MIT String Lengths

A full MIT string with tandem knuckle joints and additional centralisers has the following dimensions:

Tool Type MRO string length MRO string weight SRO string length SRO string weight
24 Finger 13.9 ft 72 lbs 9.1 ft 45 lb
40 Finger 15.8 ft 123 lbs 11.0 ft 96 lb
60 Finger 16.0 ft 161 lbs 11.2 ft 134 lb
80 Finger N/A N/A 8.8 ft 127 lb

SENSOR THEORY

• The tool is equipped with spring loaded beryllium copper

fingers with tungsten carbide coated tips. M IT S E N S O R T H E O R Y
• The arms are motored out and the casing is logged S e n s o r C o il
M ovem ent
upwards.
A c tu a to r
• As the arm encounters changes in ID it moves.
• This movement is translated via a pivot into movement of P re s s u re
B a rrie r
an ‘actuator’ within a tube shaped pressure barrier.
• The actuator acts as an inductive coupler of a coil.
• Signals are injected into either end of the coil. A c tu a to r A rm
• The position of the coil alters the output signal.
• The output signal is converted to a voltage level and
digitized. P iv o t
• The tool also has an on board inclinometer which senses
tool deviation and tool rotation.
• As the performance of the sensor coils changes with
temperature there is an on-board temperature sensor to
provide information for software temperature correction.
B e r y lliu m
• The complete tool information is encoded onto the C o p p e r fo r
M ovem ent

telemetry for transmission to surface or to the memory S o u r S e rv ic e C a rb id e T ip

O n F in g e r
recorder.

MIT LOGGING PROGRAMS

There are in effect two types of MIT job: With repeat section or without a repeat section. Repeat section jobs take
longer and are more complicated however the repeat section serves as a quality check and can help with verifying
the interpretation. The repeat section should be across the zone of interest which is usually at the bottom of the
well. Because of line stretch and the fine depth resolution of the tool, the depth of items between the main and
repeat logs may be slightly different.

Operationally Surface Readout MIT jobs and Memory MIT jobs are essentially the same. With surface readout the
tool is opened and closed on command from surface. With memory MIT the tool opens and closes at pre-
programmed times which will involve waiting until the tool is ready. Sondex provide a spreadsheet to help with
planning memory MIT jobs.

Before the job, well information (depths, deviation, bottom hole pressure and temperature, tubing sizes etc) is
required for planning purposes. If the well is very hot the time on bottom should be minimized. The well should be
shut in and a drift run should be performed so as to minimize the risk of getting the tools stuck in the well. The
engineer or operator may need to make the decision whether to exit the tubing as it is possible to encounter
problems when re-entering tubing from the casing.

__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 7 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________
The tool should be opened and closed before and after the job to check for that it is operating correctly. In
addition the fingers should be inspected before and after the job to check for finger wear.

Illustrations of the elements of jobs with and without repeat sections are below.

Example MIT logging program with repeat section (Memory MIT).

MIT Job with Repeat Section

Stop and wait Stop and wait
for tool to open for tool to open

RIH
Repeat
Depth Pre Job Section Main Log
Check / Stop and wait Stop and wait
Cal for tool to for tool to close
Run in close
Hole Pull out of hole

Open
Finger Status
Closed
Time
1) Perform a slickline drift run to below the bottom logging depth. If possible tag an item in the completion to
determine measuring wheel error.
2) Connect the battery to the Memory MIT tool. Record the battery connect time and calculate all other
opening and closing times.
3) If the tool has been programmed for a pre-job calibration, perform the pre-job calibration. Wait for the tool
to close. Rig up the tools and make zero.
4) Set zero in the depth box and start recording depth.
5) Run in hole at a maximum of 150 ft/min slowing down to less than 40ft/min to pass through the
completion items.
6) Stop at the bottom depth of the repeat section ( ft/m). Wait for the tool to open. Allow an extra 5
minutes for safety.
7) Log up at 30 ft/min to the top depth of the repeat section ( ft/m). Wait for the tool to close. Allow
an extra 5 minutes for safety.
8) Run in hole to the bottom depth of the main log ( ft/m). Wait for the tool to open. Allow an extra
5 minutes for safety.
9) Log up at 30 ft/min to the top depth of the main log ( ft/m). Wait for the tool to close. Allow an
extra 5 minutes for safety.
10) Pull the tools out of hole and rig down the tools carefully.
11) If the tool has been programmed for a post-job calibration / tool function check, the tool will open.
Perform the post-job calibration. Wait for the tool to close.
12) Stop the depth box recording.
13) Disconnect the battery from the tool.
14) Download the depth box and the memory recorder and check the data.

__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 8 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________
Example MIT logging program without repeat section (Memory MIT).

MIT Job with No Repeat Section

Stop and wait
for tool to open

Main Log
Depth Pre Job
Check / Stop and wait
Cal for tool to close
Run in
Hole Pull out of hole
Post Job
Calibration

Open
Finger Status
Closed

1) Perform a slickline drift run to below the bottom logging depth. If possible tag an item in the completion to
determine measuring wheel error.
2) Connect the battery to the Memory MIT tool. Record the battery connect time and calculate all other
opening and closing times.
3) If the tool has been programmed for a pre-job calibration, perform the pre-job calibration. Wait for the tool
to close.
4) Rig up the tools and make zero.
5) Set zero in the depth box and start recording depth.
6) Run in hole at a maximum of 150 ft/min slowing down to pass through the completion items. Pass through
the completion items at a maximum 40 ft/min.
7) Stop at the bottom depth of the main log ( ft/m). Wait for the tool to open. Allow an extra 5 minutes
for safety.
8) Log up at 30 ft/min to the top depth of the main log ( ft/m). Wait for the tool to close. Allow an
extra 5 minutes for safety.
9) Pull the tools out of hole and rig down the tools carefully.
10) If the tool has been programmed for a post-job calibration / tool function check, the tool will open.
Perform the post-job calibration. Wait for the tool to close.
11) Stop the depth box recording.
12) Disconnect the battery from the tool.
13) Download the depth box and the memory recorder and check the data.

Surface Readout or Memory?

MIT jobs can be performed as SRO or memory jobs. This is usually decided by the client though the service
company can make recommendations. With surface readout MIT logging, the tool data and depth data are merged
on acquisition. With memory MIT logging, the tool data and depth data are stored in memory and merged after the
job.

Advantages of SRO MIT operations: The prime advantage is the ability to see real time what is happening
downhole. For example to be able to repeat log zones of particular interest immediately, to be able to check that
the tools are working properly and to make on the spot decisions. If the fingers have become fouled it may be
possible to clear them by closing and re-opening the tool. If rig time is expensive, wells are waxy and if wells are
very hot it is best to perform real time operations to check that the data is optimum quality.

__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 9 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________
Advantages of Memory MIT operations: Minimal equipment is needed and thus the service is very cost effective.
The tools can be run on any slickline or coiled tubing unit and are easily transportable. There are no problems with
telemetry which can be a big factor in sour wells and where rig power is poor. Also, memory logging provides an
easy startup for new service companies and fits in well with existing coiled tubing and slickline services.

MIT LOGGING OPERATIONS

Memory Readout

M E M O R Y M IT FL O W C H A R T
TOOL D E PT H B O X
U se M em log to m ake Project S ub D irectory
E dit Service and generate project.ini file Setup D epth B ox
Setup D epth M enu
Program tool to m ake pre job calibrations

Setup Encoder
A pply pow er and m ake finger on w ireline unit
(and inclinom eter) calibrations

D ow nload Tool C heck everything is O K

Y es
No
G enerate pre job finger (and inclinom eter)
calibration files. U pdate project.ini file R ecord and test
E rase B ox
depth m easurem ent.
Program tool for job using Excel program m ing aid A ll O K ?

C onnect B attery and Set Zero and start

R ig U p T ools recording depth data

O ptionally R ecord pre job finger calibration

P erform M IT Job

R ecord post job finger calibration

D ow nload T ool data (.D A T) D ow nload D epth B ox D ata (.R A W ,.D P T)

U se M em log to M erge T ool and D epth D ata

using calibration data and T em p com pensate.
Save as .M D T file

U se M IT cal to generate:
•D epth C orrected C entralised T em p
•H istogram C orrected (optional) C om p .LA S files for
U se C A L3 or W arrior
•C entralised (L A S for M itview ) M IT view
Softw are for field prints •R epeat D epth Filtered
•D epth Zoned (optional)
•B ad Finger Interpolated (L A S only) R equires M itV iew
.C LD and .LA S files. Softw are D ongle
R equires Sondex
Print Softw are D ongle
strip Log .C LD files
G enerate M IT view
U se M IT pro to generate files for client and w rite
tabulated joint analysis report. to C D R O M
R equires M itP ro
Softw are D ongle

__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 10 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________
Surface Readout

Our standard acquisition uses a Sondex customized version of Warrior.

SRO MIT FLOWCHART (Warrior Acquisition)

TOOL DEPTH
Setup Warrior Service Software
Setup Encoder
on wireline unit

Edit Software for Depth and Finger Cal Units.

Setup Encoder Pulses in

Edit .prs file. Edit Variables for ID and OD. Header
Edit Curve Configuration

Make pre job finger (and

inclinometer) calibration files
Record and test
depth measurement

Perform Pre Job Checks

Set Zero and start

Rig Up Tools recording depth data

Perform MIT Job Run Real time

MIT Cross
section
Make post job finger calibration

Record Data into .DB files

Export to .DAT file

Use MITcal to generate:

•Depth Corrected
•Histogram Corrected (optional)
Centralised, Temp
•Centralised (LAS for Mitview)
Use Warrior software •Repeat Depth Filtered Comp .LAS files for
for field prints •Depth Zoned (optional) MITview
•Interpolated Bad Fingers (LAS only)
.CLD and .LAS files.
Requires MitView
Software Dongle

Print
.CLD files
strip Log
Generate MITview
Use MITpro to generate files for client and write
tabulated joint analysis report. to CD ROM
Requires MitPro
Software Dongle

__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 11 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________

SOFTWARE

Acquisition Software

SRO MIT logging is performed using a Sondex modified version of the Windows® based Warrior software.
Warrior offers centralized cross section on acquisition and in the near future there will be 3D imaging on
acquisition. At present (May 2004) there is no post processing software for MIT Warrior therefore the data is
exported into the .DAT previous MIT data format. This format can be read directly into the MITcal post processing
and MITpro joint analysis interpretation software.

Memory MIT logging is performed using Sondex Windows Memlog which programs the tools, merges the data
and outputs the logging passes as .MDT data format files. This format can be read directly into the MITcal post
processing and MITpro joint analysis interpretation software.

Post Processing Software

MITCal:

This is the initial post processing software. It has many useful utilities including:

• Interpolation of bad arms using adjacent arm data

• Temperature Compensation
• Centralisation and output of .LAS data for MITview
• Histogram corrections – calibration of the tool to the whole well
• Splicing of separate MIT files
• Depth shifting and depth matching of multiple depths
• Extracting data from the main file
• Re-sampling of depth to convert from time domain to depth domain
• Option for a separate heading file
• Option for a separate inclinometer calibration
• Option for a separate arm calibration
• Option write data as an MIT file for MITpro
• Option to skip data with checksum errors
• Option to filter out data marked as collars. Typically used to correct for telemetry errors
• Option to change depth units (eg ft to m)
• Option to change arm units (eg inches to mm)

USING THE DATA / INTERPRETATION

MITview:

This is the 3D imaging software. Imaging is an excellent way to convey complex information towards
understanding the damage items in the well. Different colours are mapped to different radii to enhance the image.
The data may be re-orientated towards the high side of the well. A .LOK file is generated by the software key
holder which allows the client to view and make reports from the data without a software key.

• 3D imaging orientated to the high side of the well

• 3D cross sections
• Display of dimensions of items
• Creation of .RGB colour map files
• Creation of the .LOK file to allow viewing without software key
• Creation of .JPG, .BMP and .TIFF files of screen shots for reporting (no software key required)
• Simulated tubing Outside Diameter to check for finger penetration

__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 12 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________
Example Finger Traces and 3D Images

Due to tool rotation and movement it is difficult to accurately identify damage on acquisition. It is often better to
correct the data for eccentralisation and rotation before being presented as a log. The following illustrations show
different completion items and how they appear as rotation corrected, centralized finger traces and as 3D MITview
images. MITview images are labeled as radii.

‘XN’ Nipple

The ‘N’ in ‘XN’ stands for ‘No Go’ which denotes that this nipple contains a restriction. It is usually located at the
end of the tubing and is sized such that a wireline tool / plug will not pass through it. In the middle is the locking
profile (red) where the keys on the wireline plug lock in, below this is the seal bore for a seal elements of wireline
plug (2.32” ID) and at the bottom is the no-go ring (2.23”).

Scale buildup

Scale buildup can be seen as a reduction in ID with erratic traces that reflect the roughness of the scale inner
surface. As the scale is covering the connections between the joints, it is hard to locate them.

__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 13 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________
MITview of Perforated Pup Joint: We can see that the perforations are clean.

MITpro Joint Analysis Software

Though 3D Images are excellent for illustrating the problem we also need to know the ‘real numbers’. MITpro is
used to generate joint by joint statistical analyses. First the individual joints are located semi automatically and
then they are individually analysed. Because each joint is unique the program first establishes an undamaged ID
over a specified ‘modal length’ and then measures the deviation from the undamaged ID. The results are displayed
as graphs and as listings. The format of the reports and terminology follow the established reporting procedures
for multi-finger caliper surveys. Once that the data has been processed the client can generate re-prints of the
report without the need of a software key.

MITpro Software Flow Chart

M IT Pro Analysis Flow chart

Depth Filtered File

Edit M ITpro Configuration (scales, options and units)

Locate Couplings Automatically

M anually Edit Couplings

Autom atic Analysis

Print O ut Report

No
M ITview to Check Report. No
cross check analysis Is Analysis O K ? Couplings defined
correctly?
Yes
Yes

Print O ut Report

Print O ut Final M anual Analysis

Report

Copy .SRF, .CPL, .XS* and

.PRF to disk

G ive Report to
Client on
disk for re-printing

__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 14 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________
MITpro outputs

MITpro data is output as charts, tabulations and cross sections. In general the summary charts are the most
useful. For corrosion the severity of the depth of corrosion is reported as a percentage of wall thickness and the
reduction in metal volume as a percentage of wall volume. For scale deposition the severity of the projection into
the tubing is reported as a percentage of nominal ID and the reduction in flow area as a percentage of flow area.

This chart is summary of the condition of the body regions of joints in the well. We can see that the amount of
corrosion is increasing with depth. This is not unusual. Because the corrosion is in pits, though the penetration is
high, the percentage of metal loss is low. At the bottom of the well there is a hole.

This is a section of the numerical listing of the data at the bottom of the well.
__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 15 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________
CASE HISTORIES

A: Quantifying scale buildup and to gauge the success of the subsequent scale chemical cleanup job.

The client was experiencing trouble getting wireline tools down the well and the field had a history of scale
deposition. An MIT job was performed using a Sondex 24 finger memory Multifinger Imaging Tool run on slickline.
This showed the well to have scale buildup increasing in severity downwards. Following the survey a chemical
solvent was used together with coiled tubing to cleanup the well. During the cleanup job problems were
encountered and it was not possible to pass below joint 315.

Using MITview we can visually gauge the effectiveness of the cleanup job. The two images below are from the
same depth in the well at the bottom of the cleanup job. Green represents nominal ID, blue is a reduction in ID.

MITview of scale in the well before cleanup job Same depth (Upper extent of scale after cleanup).

The post cleanup image shows that the tubing has been effectively cleaned down to joint 315. Corrosion items on
the lower side of the pipe were formally obscured by the scale can now be seen including a defect severe enough
to be a hole.

As well as quantifying damage, the MITpro statistical analysis

program outputs the minimum ID seen in each joint after
centralisation. By charting this data we can compare pre and
post scale cleanup data sets to gauge the effectiveness of the
cleanup job.

After the scale cleanup job we can see that the tubing is
consistently clean but there is still a slight reduction from
nominal. This could be remaining scale deposits, reductions in ID
during manufacture or from making up the pipe during the
completion of the well.

Below the lowest depth of the cleanup job we can see close
agreement between the pre and post scale cleanup jobs. This
gives us confidence in the quality of the data which was
recorded by different tools after a six month interval. It also
means that wireline problems at the bottom of the well will
continue because the scale has not been cleaned out.

B: Problems with Sliding Side Doors

In this well the client suspected that a sliding side door was damaged. However after setting a wireline plug in the
profile at the top of the damaged SSD the tubing would not pressure test and so the client suspected a hole in the
tubing. An MIT job was performed to establish where the damage may be.
__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 16 of 17
 Multi Finger Imaging Tool MIT
_________________________________________________________________

MITview 3D image of Upper SSD MIT3D image of Lower SSD

The MIT shows that the upper SSD in the well is not fully closed (we can see the flow ports) and thus acting as a
hole in the tubing. The lower SSD is closed as the inner sleeve has been shifted down but, as the client suspected,
has been washed out by flow and is leaking.

MAINTENANCE

The Sondex MIT tools are fairly maintenance intensive in that the fingers wear out and need to be changed.
Typical lifetime of the fingers is 40-70,000 ft but this will be reduced in wells which are badly damaged, have high
levels of scale and have high concentrations of H2S and CO2 (which results in the tubing being etched). It is
important to inspect each finger before and after the job for wear of the tungsten carbide tip. If the wear is light,
the fingers can be re-tipped.

In addition, seals, ‘O’ rings and springs should be changed periodically. If the tools are maintained and run
carefully they will last a long time and the usual lifetime of the tools is 5-8 years.

For memory MIT batteries should be changed. A rule of thumb is new memory battery every 5 wells and a new
motor battery every 10 wells.

Tool Routine Maintenance

Roller Centralisers Change rollers as required. Inject grease through grease ports. Change ‘O’ rings.
Check continuity and insulation.
Knuckle Joints Inject grease through grease ports. Check continuity and insulation.
Swivel Joint (if used) Change ‘O’ rings. Refill with silicon oil as required.
MIT tool Clean the tool thoroughly after a job (do not use a pressure hose). Inspect and change
fingers, seals and ‘O’ rings as required. Inspect springs. Grease the fingers and
actuators. Before the job perform a calibration and check the tool and fingers open
and close smoothly. Check for any loose screws. Check that tool does not go into
‘current limit’ on opening or closing.
Batteries (memory MIT) Monitor usage by recording time used (not voltage) and change if necessary.

STORAGE / TRANSPORT

The tools should be oiled with WD40 to prevent possible corrosion and transported in carrying tubes within foam
lined protective boxes. We recommend to put about 2” of diesel in the carry tube with the tool. The watertight end
caps should be fitted. The tools should be protected against shock during transport.

Lithium batteries which are required for Memory MIT are subject to special transportation procedures.
Please refer to Sondex for a safety data sheet covering the transport of these batteries.

__________________________________________________________________________________________________________________________
Copyright © Sondex 2004 All Rights Reserved. Version 1.0 Page 17 of 17