ImageLog Processing & Procedures
Updated: October 2003 IMAGELOG.DOC
IMAGELOG PROCESSING
1- TABLE of CONTENT
IMAGELOG PROCESSING ... 2 1- TABLE of CONTENT ... 2ACKNOWLEDGEMENT ... 3
HISTORY ... 8
OVERVIEW ... 8
IMAGE RECORDING TOOLS SUPPORTED by PETROLOG ... 8
RECOMMENDED SOFTWARE MODULES... 9
RECOMMENDED HARDWARE ... 9
FORMATION MICRO-SCANNERS: The differences... 9
Micro-Scanners v Sonic Images: ... 10
MEASUREMENT WHILE DRILLING ... 10
TOOL CONFIGURATIONS ... 11
DATA LOADING - GENERALITIES ... 19
SHDT/FMS DATA IMPORT ... 20
1- Copy LIS or DLIS tape to the Hard Disk... 20
2- Create Verification Listing ... 20
3- Load FMS Image Data ... 21
4- Load SHDT Data ... 22
FMI DATA IMPORT... 23
1- Copy DLIS or LIS Tape to Hard Disk ... 23
2- Create Verification Listing ... 23
3- Select Logs and Arrays ... 24
OBMI DATA IMPORT... 25
4- Copy DLIS or LIS Tape to Hard Disk ... 25
5- Create Verification Listing ... 25
6- Select Logs and Arrays ... 26
EMI DATA IMPORT ... 27
1- Copy LIS or DLIS tape to Hard Disk ... 27
2- Create Verification Listing ... 27
3- Select Logs and Arrays ... 28
STAR DATA IMPORT ... 29
1- Copy LIS or DLIS tape to the Hard Disk... 29
2- Create a Verification Listing ... 29
3- Select Logs and Arrays ... 30
CBIL/UBI/USI/AST/SAS/DMT-BHTV DATA IMPORT... 31
1- Copy LIS or DLIS tape to the Hard Disk... 31
2- Make a verification listing ... 31
3- Select Logs and Arrays ... 32
Mining Logging Contractor DATA IMPORT ... 33
2- Robertson Geologging Australia ... 33
3- Century... 34
MWD Image Tools... 35
1- Schlumberger RAB (Resistivity at Bit) ... 35
2- Schlumberger ADN (Azimuthal Density Neutron) ... 35
3- Baker Hughes APLS (Azimuthal Density Neutron) ... 36
4- Common Aspects for processing ... 36
PRE-PROCESSING ... 37
1- Add DIPI, AZI, DIPS, and DIPQ Log Names to the Data File... 37
2- Normalize Log Names and Units ... 38
3- Interpolate Missing Values (Slow Channel Speed logs) ... 38
GRAPHICS ... 40
1- Creating a Presentation Plot ... 40
3
2- De-Stripe / Button Normalize ... 54
3- Compute Accelerometer Corrected Depths... 55
4- Apply Accelerometer Depth Corrections... 62
5- Pad / Button Depth Shifts ... 67
6- Tool Tilt and Arm Swing Correction ... 70
7- Compute 6 Calipers from Sonic Image Transit Times ... 76
DIP EXTRACTION FROM PROCESSED IMAGES... 78
1- Create a Presentation Plot with Results ... 78
2- Add DIPS ... 79
3- Modify DIPS ... 82
4- Delete DIPS ... 83
5- Modify DIP Status ... 83
6- Duplicating Dips ... 84
7- Adding new DIP Status to the Default Table ... 84
8- AutoDip ... 85
9- True and Apparent Dip: a manual cross check ... 91
10- Structural Dip Removal ... 91
11- Correction of Imagelog Dip Bug ... 92
12- Extracting Dips from a Deviated Well... 95
13- Re-computing Existing Dip Results using Computed PD1N ... 99
14- Exporting Dip Results to a Text File... 101
VOLUMETRICS ... 103
DIP EXTRACTION FROM CORE PHOTOS... 109
1- Convert Photo Image to JPEG file ... 109
2- JPEG to RGB format ... 109
3- RGB to DAT format ... 109
4- View DAT file Curve Data... 110
5- Add PAD 1 AZIUMTH, DIPI, DIPS, DIPQ and AZI... 111
6- Display the Core Data Array Image ... 112
7- Extracting Dips from the Core Image... 114
STEREONET & ROSE PLOTS... 115
1- Tadpole Azimuth Rose Plot... 115
2- Stereonets... 116
OTHER GRAPHICAL PRESENTATIONS ... 118
1- Add TVD / MSL / Accelerometer Corrected Depths ... 118
2- NGT Image as Background to the Micro-Scanner Images ... 119
3- Fracture Frequency Generation ... 120
4- Processed Image Export ... 121
5- Adding Symbols and Remarks ... 122
6- Orientating Image Logs to the “top and bottom” of deviated holes... 125
7- SHDT Display. ... 126
DIP INTERPRETATION ... 129
1. Introduction ... 129
2. Structural Dip Interpretation ... 129
3. Sedimentologic Dip Interpretation Techniques... 135
4. Clastic Environments... 141 5. Carbonate Environments... 152 6. Borehole Mechanics ... 155
FURTHER READING ... 158
1- General ... 158 2- Fracture Evaluation ... 158 3- Speed Corrections ... 158 4- New Tools ... 1585- Thin Bed Analysis ... 158
ACKNOWLEDGEMENT
The material contained in this manual has been compiled from a variety of sources. There are some sources which we have not been able to acknowledge. If in reading this manual you find reference to material that has not been properly acknowledged, please contact Crocker Data Processing Pty Ltd on [email protected] or alternatively write to us at Crocker Data Processing Pty Ltd, Unit 1, 12 Brodie Hall Drive, Technology Park, Bentley, WA, 6102, Australia.
Some specific acknowledgements I would like to make:
1) Present and previous employees of Crocker Data Processing that have compiled much of the material describing the use of the software, in particular Dinah Pantic who compiled much of the extensive document in front of you.
Acoustic Tools
AST & SAS REEVES Acoustic tools
UBI SCHLUMBERGER Ultra Sonic Borehole Imager
USI SCHLUMBERGER Acoustic tool
CBIL BAKER ATLAS Circumferential Borehole Image Log CAST HALLIBURTON Circumferential Acoustic Scanning Tool ABI 40 ALT slim hole Acoustic Televiewer
DMT
Electrical Tools
EMI HALLIBURTON 6 pad micro-resistivity tool HMI COMPUTALOG 6 pad micro-resistivity tool FMI & FMS SCHLUMBERGER 4 pad micro-resistivity tools
OBMI SCHLUMBERGER 4 pad micro-resistivity tool for oil based mud ARI SCHLUMBERGER deeper investigation micro-resistivity tool AND SCHLUMBERGER Density/Neutron tool – provides a nuclear image RAB SCHLUMBERGER Resistivity at Bit tool (LWD)
STAR BAKER ATLAS 6-pad image tool
Combination Tools
STAR IMAGER ATLAS 6-pad image tool combining Acoustic & Electrical measurements (CBIL & STAR) EARTH IMAGER BAKER ATLAS 6-pad micro-resistivity image tool for oil based mud (not yet released)
Video Imaging
DHV HALLIBURTON Downhole Video Service
BIPS COLOG Borehole Image Processing System (camera based) OBI 40 ALT slim hole Optical Televiewer (camera based)
5
Figures
Figure 1 LEFT - Single button HDT pad RIGHT - SHDT 2 button array ... 11
Figure 2 FMI sensor geometry and Schlumberger Image Tool comparison chart ... 12
Figure 3 FMI Tool Geometry... 13
Figure 4 The pad and flap array of the Schlumberger FMI tool ... 14
Figure 5 Picture of the Schlumberger OBMI micro-resistivity tool for use in non-conductive oil based muds ... 14
Figure 6 Configuration of the Schlumberger OBMI pads... 15
Figure 7 A typical STAR-log pad construction... 15
Figure 8 A typical HMI log pad construction. ... 16
Figure 9 A diagram of the HLS EMI tool. ... 17
Figure 10 The EMI pads. ... 18
Figure 11 A typical Sonic Image Tool... 18
Figure 12... 21
Figure 13 Sorted FMS buttons... 21
Figure 14 The above figure shows the menu that creates a new DAT file... 22
Figure 15 A typical DLIS file containing multiple files (x9) including Super Combo, FMI and CMR data sets... 24
Figure 16 Typical FMI logs that have been recorded simultaneously with a NGT tool. ... 24
Figure 17 A typical DLIS, OBMI data set. ... 25
Figure 18... 26
Figure 19 A typical EMI log... 28
Figure 20 The above figure shows log selection. ... 30
Figure 21 A typical Atlas STAR fast channel set (in file #3) and logs and arrays required for loading. ... 30
Figure 22 A typical UBI set of logs and arrays for download with the LDT simultaneously recorded... 32
Figure 23 LIS or DLIS logs with long log names. ... 37
Figure 24 The above menu shows the additional 4 new curves, DIPI, AZI, DIPD, DIPS inserted into an FMI data set.
... 38
Figure 25... 38
Figure 26 The Main Menu for interpolating “null values” in a file... 39
Figure 27 The above figure shows a series of standard plot templates. ... 40
Figure 28 The above illustrates a typical presentation plot menu. ... 41
Figure 29 The default Plot for EMI Static and Dynamic. ... 42
Figure 30 A typical default Pad Image Menu... 43
Figure 31 The various options in the Pad Image Menu for Pad Scaling. ... 44
Figure 32 A typical listing of EMI field data... 45
Figure 33 The above shows the effect of negative values on the EMI image. ... 45
Figure 34 Three different image presentations. ... 46
Figure 35 Histogram of resistivity data ... 47
Figure 36 Manipulation of histogram limits ... 47
Figure 37 The Static image improved using the histogram of all button values within a file... 48
Figure 38 The Image Colour Palette default tables ... 49
Figure 39 The default White-Yellow-Red-Brown-Black range with the number of divisions increased to 96... 50
Figure 40 Raw, unprocessed EMI results with the static image ... 51
Figure 41 The Star raw field data image. ... 53
Figure 42 The Star Emex Correction menu ... 54
Figure 43 The above figure shows the De-Stripe Normalize menu... 55
Figure 44 The above illustrates a typical presentation result for EMI (HLS tool) data in a near horizontal well... 56
Figure 45 The above illustrates a typical Schlumberger FMI accelerometer data set... 57
Figure 46 This figure illustrates a typical presentation of the tool pusher EMI from HLS. ... 58
Figure 47 The above illustrates the speed correction menu... 59
Figure 48The first pass results from speed corrected depths... 60
Figure 49 The above illustrates the PETROLOG standard Speed Correction plot. ... 61
Figure 50 This illustrates the Speed Correction Depth Shift main menu. ... 62
Figure 51 HMI Dynamic image showing evidence of tool stick ... 63
Figure 52 Speed correction window... 63
Figure 53 Image display modified to include Track 4: Uncorrected tool acceleration ACLT & Zero offset tool
acceleration ACLZ... 64
Figure 54 This figure shows the multiple Speed Correction results in columns 203-226... 64
Figure 55 The Alternate Depth Menu for the first set of Depth Correction results... 65
Figure 56 The Pad Image Menu, Data Corrections pop-up menu with the Apply Speed Corrected Depth Shift
function ... 65
Figure 57 The above figures illustrate the results after applying speed correction from good accelerometer data66
Figure 58 The above illustrates a typical correction menu for EMI and STAR tool row correction. ... 68
Figure 59 A typical pad correction instruction set for even pad displacement, EMI tools... 69
Figure 60... 70
Figure 61 The options available for setting up Dip Interpretation procedures... 71
Figure 62 A typical pad arrangement. ... 72
Figure 63 Effect of deviation ... 73
Figure 64... 74
Figure 65 Edit window in log editing showing Sattus types. ... 75
Figure 66 Illustrating types of manipulation labels... 75
Figure 67 Select Compute Calipers from Sonic image transit time as shown above... 76
Figure 69 The above illustrates default presentation plot 47, which includes the DIPI/AZI/DIPS/DIPQ tadpole track.
... 78
Figure 70 Editing image data... 79
Figure 71... 79
Figure 72... 80
Figure 73 The image editor menu... 81
Figure 74... 81
Figure 75 The MODIFY menu that allows fine adjustment of DIPI, AZI and tadpole depth... 82
Figure 76 The list of available dip status as in your default table. ... 83
Figure 77 The Status default-editing menu. ... 84
Figure 78... 85
Figure 79... 85
Figure 80. ... 86
Figure 81 Main screenplot menu... 86
Figure 82 Resistivity curve addition menu... 87
Figure 83 Tadpole Menu ... 87
Figure 84 Dip sinusoid menu ... 88
Figure 85 Auto dip computation warning window ... 88
Figure 86 Parameter selection... 89
Figure 87 Parameter selection menu ... 89
Figure 88 Computed results... 90
Figure 89... 91
Figure 90 To effect the corrections, go to the Main Plot Menu and from Line 17, select Tadpole Sinusoid as shown
above... 92
Figure 91Select the box at the bottom “ImageLog Dip bug correction”... 93
Figure 92 Bug correction menu... 93
Figure 93 Edit window with new and old azimuth/dip curves highlighted ... 94
Figure 94... 95
Figure 95... 96
Figure 96... 96
Figure 97... 97
Figure 98... 97
Figure 99... 98
Figure 100... 99
Figure 101... 99
Figure 102... 100
Figure 103... 100
Figure 104... 101
Figure 105... 101
Figure 106... 102
Figure 107... 102
Figure 108... 102
Figure 109 The Image Log Volumetric Menu for a DMT file. ... 103
Figure 110 The drop down window option for naming the individual divisions. To change any of these click on
the Name that needs to be changed. ... 103
Figure 111 The above figure illustrates the naming options available. ... 104
Figure 112 The pop-up window that allows the user to chose the histogram interval specifications ... 104
Figure 113 The cutoff limits can be changed for each depth interval by clicking on the depth interval box in the
Histogram View. ... 105
Figure 114 The Cut-Off Histogram for an FMI log ... 105
Figure 115... 106
Figure 116 The cutoff Histogram View ... 106
Figure 117 The Image Log Volumetric Main Menu with drop down window indicating the options for report output
... 107
Figure 118 The Plot Curve Menu showing the addition of the 4 new Stepping Curves (7-10) and their display
parameters ... 107
Figure 119 The Stepping Curves are displayed in Track 3 as a pseudo lithology... 108
Figure 120 The above figure illustrates a PCX file (1000 * 1089 * 16 million colours) of a Core photo. ... 109
Figure 121... 110
Figure 122 180 arrays are created from the RGB image of the core photo. ... 110
Figure 123 Creation of Pad1azimuth through log function. ... 111
Figure 124 Core caliper and azimuth image presentation screen. ... 111
Figure 125... 112
Figure 126... 112
Figure 127 Core image at 1:7... 113
Figure 128... 113
Figure 129 Sunusoid menu set up... 114
Figure 130 Tadpole track set up. ... 114
7
Figure 135 A typical DMT Sonic image with Dips, Azimuth Rose plot and Schmidt/Walkout plot every 5m of hole.
... 118
Figure 136 NGT and EMI images superimposed... 119
Figure 137 Fracture frequency generation. ... 120
Figure 138 Fracture frequency generation. ... 120
Figure 139 Status selection. ... 121
Figure 140 The above figure illustrates the menu for Image export... 121
Figure 141 The two available Processed Image display templates ... 122
Figure 142... 122
Figure 143 Fully annotated interpretation... 123
Figure 144 The pad image of the Schlumberger FMS tool. Each pad has 2 rows of 8 buttons each. The pad width
is therefore 1.6 inches... 124
Figure 145 The list of available symbols... 125
Figure 146 Display of SHDT data as curve and pad images ... 126
Figure 147Track set-up for the SHDT display. ... 126
Figure 148 The Pad Image Menu for the display of Dipmeter data as a Pad Image ... 127
Figure 149 This figure shows the menu path to create a Dip Resistivity plot ... 127
Figure 150 Dip Stick curve menu ... 128
Figure 151 Structural dip illustrated by the green tadpoles. Dip is approximately 300/03 deg. ... 129
Figure 152 Figure showing stick plot versus seismic... 130
Figure 153 Figure showing Fault drag and the resultant dip pattern ... 130
Figure 154 Images showing small scale faulting (both images cover a 2 Metre Interval) ... 131
Figure 155 Images showing fractures illustrating a conjugate set... 131
Figure 156 Determination of true fracture spacing ... 132
Figure 157 Fold identification from unknown reference. ... 132
Figure 158 Bengston (1981) Figure 2 showing the different scatter patterns for different tectonic settings. ... 133
Figure 159 Bengston (1981) Scatter patterns for different tectonic settings... 134
Figure 160... 135
Figure 161 Structural Dip illustrated. This example shows a 3 degree NW... 136
Figure 162 Red dips show red pattern showing an East structural dip... 136
Figure 163 Structural Dip illustrated. This example shows a 3 degree NW... 137
Figure 164 Comparison of Campbell (1964) with Miall (1996)... 138
Figure 165 Coloured column shows zonation as per bedding. Note the yellow zones have clasts and little
bedding.) ... 139
Figure 166 Coloured column shows zonation as per bedding. Note the yellow zones have clasts and little
bedding.) ... 139
Figure 167 Walkout Plot showing dip trend from previous Figure ... 140
Figure 168 Bioturbation/Fabric Index – note the yellow zones are low and the red zones moderate... 140
Figure 169 Braided Channel Stylised Example (Source Unknown) ... 142
Figure 170 Meander Point Bar Stylised Example (Source Unknown) ... 143
Figure 171 Lucustrine Delta Fill Stylised Example (Source Unknown) ... 144
Figure 172 Bay Fill Stylised Example (Source Unknown) ... 145
Figure 173 Abandoned Distributary Stylised Example (Source Unknown) ... 146
Figure 174 Abandoned Distributary Mouth Bar Stylised Example (Source Unknown) ... 147
Figure 175 River Mouth Bar Tidal Ridges Stylised Example (Source Unknown)... 148
Figure 176 Subaqueous Slumps Stylised Example (Source Unknown) ... 149
Figure 177 Bouma Units for a Turbidite ... 150
Figure 178 Use of walkout plot and rose plot to identify channel axis and paleocurrent direction. ... 150
Figure 179 Shoreface sand body showing consistent SW progradation.. ... 151
Figure 180 Shoreface sand body with bioturbation.. ... 151
Figure 181 Dune sand... 152
Figure 182 Drape over carbonate reef... 152
Figure 183 Image over a limestone ... 153
Figure 184 Dunham’s Classification Scheme ... 154
Figure 185 Typical Reef... 154
Figure 186 Borehole ovality from calipers. ... 155
Figure 187 Tensile Fractures.. ... 156
Figure 188 Stress Regime around a borehole where a biaxial stress regime is applied and ratio is 2:1(Reproduced
from Figure 5, Bell, 1990). ... 157
HISTORY
As far back as late 19th Century it was apparent that there would be advantages in the ability to visualize rocks being drilled deep beneath the earth’s surface. Methods were devised to bring core to the surface however this did not resolve in situ visualization so in the early 1900’s attempts were made to take downhole photographic images. Many years later this was followed by video imaging in the 1970’s. The constraint on these two methods is that they require a clear borehole fluid for good image capture. To overcome this, the electrical Dipmeter tool was developed during the 1930’s. This was the precursor to the modern Electrical Microscanner tools. Initially using 3 arms it later became the 4 Arm Dipmeter with a single button on each Pad. Further developments introduced 2 buttons per pad. Processing of Dipmeter information is wholly mathematical and produces fluctuating results not necessarily related to geological reality therefore a better approach was investigated and the more sophisticated Schlumberger FMS (Formation Micro Scanner) array resistivity tool subsequently replaced the Dipmeter. There are now several microscanner imaging tools on the market, all of which are array tools producing multiple data records at each depth step and high resolution images.
The Borehole Tele Viewer concept was the precursor to the modern Acoustic Imaging Tools that have been in use since the late 1960’s.
The purpose of Imaging Tools is to see;
1) Geological features: to further our understanding of the sub-surface environment from an exploration and development perspective. • Bedding e.g. crossbeds, ripples, thin beds, graded beds
• Structure Analysis e.g. detection of bedding dip, folding, faults, slumping • Features e.g. geological fractures, burrows, vugs, pebbles, stylolites. • Thin bed analysis
• Borehole breakout analysis • Lithological characterisation
2) Non-Geologic features created by drilling/logging: leading to optimization of drilling techniques. Inspection of casing.
Image logs can picture fine scale features. To interpret the logs the user must understand individual tool types, how the data is gathered and data processing techniques. Image acquisition is very costly and useless or misleading if correct procedures are not adhered to. Interpretation requires a depth of experience and knowledge. The ability to discern both Geologic AND Non-geologic features (artifacts) is important.
OVERVIEW
PETROLOGis a log manipulation and log analysis software package. ImageLog is a module of PETROLOG and is used as a general-purpose borehole imaging software that can process most known contemporary logging tools. As new tools evolve, these can easily be added, on request.
Formation Image logs are different from other Open Hole (OH) logs in construction characteristics and image recording methods and the particularities of each tool must be handled accordingly. Measurements are essentially the same (sonic amplitudes or formation conductivities) but the number of readings and the physical orientations of the sensors differ from tool to tool.
Important
Borehole image files are usually very large and processing times will be longer than on regular OH interpretations, therefore be well organized from the start to avoid time-consuming mistakes.
• The back page of this manual is a Step-By Step procedure list. Make multiple copies and use for each image processing job. • There are no shortcuts. Follow procedures rigidly to achieve outstanding results.
IMAGE RECORDING TOOLS SUPPORTED by
PETROLOG
PETROLOG can process most known image logs including;
MICROSCANNERS
• EMI (6 pads 150 buttons) • FMS (4 pads 48 buttons) • FMI (4 pads, 4 flaps, 192 buttons) • OBMI (4 pads, 40 buttons) • STAR (6 pads 144 buttons)
These are array Pad devices recording individual button curves. Button voltage may vary. The data file contains Fast and Slow channel speeds.
Artifacts:
Ÿ Tool sticking
Ÿ Differences in pad friction with borehole Ÿ Pad/Button offset
Ÿ Conductivity path is passive and sometimes complex producing Halos & Proximity effects
SONIC IMAGES
• AST (250 arrays) • SAS (250 arrays) • UBI (160 or 180 arrays)
• Most other Sonic Image tools with arrays up to 400 values per 360 degree rotation. Artifacts:
Ÿ Tool Sticking Ÿ Hole spiraling
9
RECOMMENDED SOFTWARE MODULES
PETROLOG modules required for processing formation images: • LIS (Import-Export)
• DLIS (Import-Export)
• LAS (for import of channel logs)
• Data Manipulation (function, repair, patch and interpolate slow channel logs) • Data Reporting (calibrate images as resistivity traces using X-plot and best fit curve) • Screen Plot editor (customized presentations and access ImageLog)
• ImageLog
• Pen Plot (plot output to various devices e.g. HP plotter, Epson Printers or various file formats e.g. GIF, JPEG, PCX, TIFF, EPS, CGM etc.)
• Log Processing for removal of structural dip • Macro-Editor
It is assumed users are familiar with PETROLOG and accessing PETROLOG modules. Crocker data Processing (CDP) training videos and help files give step-by-step instructions for each module.
RECOMMENDED HARDWARE
Image data files are typically very large and the choice of computer is important:
UNIX Workstations: (Solaris 2 or IBM AIX or PC-LINUX)
256 Mbytes of RAM with a minimum 36 Gb free disk space.
PC:
• Pentium III 866 Mhz or better
• 256 Mbytes (133 Mhz SDRAM or RDRAM) • 21” Screen (64 Mb GeForce D2 video card) • 36 Gb SCSI 3 hard disk drive with SCSI 3 card • SCSI2 card for external tape drives
• Win NT or Win2000 operating system
All Systems:
• 8 mm Exabyte drive
• 4 mm DAT drive (DDS-3 recommended) • CDROM drive
Note: Field tapes can be large and easily exceed 1 Gb in size. Slow drives such as the DDS-1 and DDS-2 DAT drives can take hours to
download a tape.
FORMATION MICRO-SCANNERS: The differences
Tool type
Hole coverage 8.5” hole
Button
depth shift
Pad
Depth
Shift
# Calipers
# Buttons
EMI
15.0”=57%
0.3”
2.5”
6
150
FMI
19.2”=72%
0.3”
6.0”
2
192
STAR
14.4”=54%
0.3”
3.4”
6
144
The ideal tool should have: • Maximum hole coverage
• Minimum pad distance (to reduce accelerometer corrections) • 6 or more independent calipers (hole-ovality)
Image quality also depends on the depth of investigation and the focusing ability of the electronics. Logging companies do not currently publish this information.
In rugose and highly deviated wells, CDP consider the HLS EMI has a slight advantage on other tools.
Logging Company Imaging Characteristics:
Choosing the optimum logging tool will depend on operating company requirements/expectations and downhole parameters.
EMI: (HLS)
• Tape writing errors result in readings stored as negative of true value. The solution to this is to plot absolute array values. • RB, P1AZ, GR, DEVI and HAZI are recorded at 6-inch slow channel speed. When written to LIS at a faster channel speed,
these logs are duplicated to generate a square log. In fast rotating sections the image is therefore moving by step. Solution: load these logs at 0.6 inches and then merge to the fast channel data file and interpolate the values correctly.
• Metric EMI are stored at a 0.0025m depth increment (about 0.092 inches). The buttons are exactly 0.3 inches apart and depth corrections are therefore incorrect. Preferably store the logs in feet, in the field, to avoid this error.
• EMI has one button on each pad that measures shallow resistivity instead of Micro-Resistivity thus allowing direct calibration with other OH wireline Resistivity logs.
FMI: (Schlumberger)
• DLIS format allows long log naming; this easily identifies which curves to load.
• Rugose hole conditions can cause the flap to rotate in or out therefore it does not always read perpendicular to the hole wall.
STAR (Atlas)
• Records button readings as one-byte words.
• Requires a button gain correction. Since the GCOD (EMEX) is applied on the basis of the average values on one pad, other pads may saturate and become useless.
• Requires button calibration (De-Stripe option) more than other tools.
• STAR Imager tool is a Combo tool recording both Electrical and Acoustic Images. The Electrical component is similar to the Schlumberger FMS and the Acoustic is the Baker CBIL tool.
The above information is derived from CDP findings to date and based on data received from the field. Tool characteristics will most likely improve in the future.
Micro-Scanners v Sonic Images:
Tool Type
Depth of
Investigation
Mud Cake
Effect
# Calipers
Mud
Effect
Vertical
Resolution
Hole
Coverage
Micro-Scanner
0.5 to 2”
Low
< 6
Low
0.1”
<72%
Sonic
Image
0.0
High
72 – 288
High
0.2 - 0.4”
100%
Micro-Scanners have a definite advantage in accurately computing dips, however, hole coverage is limited and vertical fractures may be missed. Dips are dependent on the depth of investigation, which is dependant on the formation conductivity. These tools normally require a Water based mud system. The OBMI (Schlumberger Oil Based Micro-Imager tool) and the EARTH Imager (Baker Atlas) are designed to acquire images in oil based muds with greater than 50 ohmm mud resistivity.
Sonic Images offer 100% hole coverage but poor vertical resolution. Thick mud-cakes hide formation fractures and beddings. The 160 to 250 transit time measurements are equivalent to 160 to 250 calipers and can be used to draw a true view of hole breakout/ovality. If the tool position is not eccentered properly then non-viable images will result. These tools are run in an Oil based Mud System.
Newer Sonic Transducers can focus beams to about the same resolution of Micro-Scanners (0.2 inches or 2 degrees).
MEASUREMENT WHILE DRILLING
Measurement While Drilling (MWD) techniques have come a long way since the first tools were introduced in the late 1980’s. Azimuthal measurement drilling was introduced in the 1990’s and this meant real time geo-steering and image acquisition resulting in reduced rig time and more accurate drilling control. Schlumberger’s GeoVISION technology allows viewing of fullbore images in real time however the resolution is significantly lower than the conventional micro-resistivity FMI(x5) and images can only be obtained when the drillstring is rotating. MWD image measurements are most useful in highly deviated holes with bedding is roughly parallel to the borehole.
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TOOL CONFIGURATIONS
FMS is available in 3 versions. Each button is recorded separately in the LIS or DLIS format field tape. • 2 pads with 27 electrode image arrays and 2 dip pads
• All 4 pads with 16 electrode image arrays • Slim hole tool with 4 pads of 16 electrode arrays
The most commonly used FMS is the 4 Pad, 16 Button/pad array. Button values from FMS logs are stored at random, it is important to sort them before loading to PETROLOG.
FMI has 4 pads and 4 flaps, each with 2 rows of 12 buttons. Each 12-button array is stored separately in the field tape.
OBMI has 4 pads, each with 2 rows of 5 buttons.
To avoid selecting individual buttons separately in PETROLOG, define the array size and select the 1st value of the array. Generating graphics is thus simple and easy.
Figure 1 LEFT - Single button HDT pad RIGHT - SHDT 2 button array
It is possible to create a realistic image from the 2-button array of the SHDT and extract dips interactively from this presentation (see section on Other Graphical Presentations/ SHDT Display).
13
Figure 4 The pad and flap array of the Schlumberger FMI tool
Figure 5 Picture of the Schlumberger OBMI micro-resistivity tool for use in
non-conductive oil based muds
15
Figure 6 Configuration of the Schlumberger OBMI pads
1
7
13
14
25
Downhole
Upper (1,3,5)
1
2
3
4
5
6
x
y
Looking Downhole
z
Lower (2,4,6)
1
7
13
14
25
Downhole
0.30 0.2017
Figure 10 The EMI pads.
Figure 11 A typical Sonic Image Tool.
• The transducer rotates at 7.5 RPS and takes from 160 (UBI from Schlumberger) to 250 (AST from Reeves) readings per rotation. • The Slim-Hole DMT BHTV (40mm diameter) rotates at up to 10 RPS and takes 72, 144 or 288 samples per rotation.
• At 7.5 RPS, a tool travels 0.4 inch per rotation at a logging speed of 900 FPH. • Distance traveled for one rotation = 12inch x 900 fph/3600sec / 7.5RPS = 0.4 inches. • It is possible to log at 450ft/hr and obtain measurements at 0.2-inch depth increments.
• UBI and STAR tool transducers are situated in a fluid filled chamber to achieve Acoustic Coupling of Transit Times between the Borehole Mud and Tool. The Transducer produces signals that travel out and bounce off the borehole wall to return to the
19
DATA LOADING - GENERALITIES
• Good understanding of the physical construction of different tools and the way field tape data is stored will help in loading and processing Image Log data as logging companies store their image data in different ways.
• The user must be able to identify arrays and other logs to download.
• PETROLOG automatically identifies most of the individual traces required for downloading. Arrays must be manually selected. • OH log readings are recorded at different depth increments (Channel Speed) to high-resolution button readings. Typically standard
logs are recorded at slow channel speeds of 6 inches and the latest image data at fast channel speed of 0.1 inches.
• Slow channel speed logs to load:
§ Pad 1 Azimuth P1AZ, AZ, AZI1
§ Bit Size BS, BIT
§ Gamma Ray GR
§ Hole Azimuth HAZI, DEV, DAZ, AZIM
§ Hole Deviation DEVI, DEV
§ Relative Bearing (Hole deviation to P1AZ) RB
§ Tool Body Mark Orientation Offset RBOF (STAR logs only) § Older tool types: Emex current code EMEX, GCOD, GCO1 etc
§ All Calipers or Radii (Radii mnemonics must start with an R….) C1 and C2, CAL1-CAL6, RAD1-RAD6 • Fast channel speed logs to load:
§ FCAX, FCAY, FCAZ accelerometer data (AX, AY, AZ is the slow channel equivalent), Cable Speed, Time § For Micro-scanners, load all Button Arrays
§ For Sonic Images or Borehole Tele-Viewer, load both Amplitude (AWBK, BHTA) & Transit Time arrays (TTBK, BHTT)
One of the most difficult components when generating images is loading appropriate curve data.
NOTE: If no P1AZ or DEVI is available in an image file, these can be calculated using the accelerometer and magnetometer data.
PETROLOG has a User Algorithm to create these columns. Firstly ensure that accelerometer (FCAX, FCAY, FCAZ) and magnetometer data (FX, FY, FZ) are available. The algorithm required for the computations is called P1AZ_DEVI.ALG.
To run this algorithm
• Main Menu: 12 Log Manipulation
• Log Data Manipulation Menu: 9 User Algorithm • Select P1AZ_DEVI.ALG
• Enter input columns • Select output column • Run the algorithm
Your computer MUST have a C compiler installed to use the user algorithm feature e.g. Microsoft Visual C++ or Sun C/C++ compiler.
The default compiler (line 7 of the User Algorithm menu) is c1 ?????.C (c1 is the command to compile using the MS C++ compiler.) Replace this command as required if you use a different compiler. If you do not have a C compiler available you can install the free compiler on the CD-ROM with PETROLOG (please read the readme.txt file on the CD).
SHDT/FMS DATA IMPORT
For more details see TRAINING menu 1: IMPORTING DATA
Copy field tape data to hard disk using a third party software or PETROLOG DLIS or LIS modules.
1-
Copy LIS or DLIS tape to the Hard Disk
•
Use the appropriate LIS or DLIS module to copy the tape to disk.•
It is recommended that the file name should easily identify the data source e.g. Wellname_FMI.*2-
Create Verification Listing
Automatically done when loading directly from LIS or DLIS to DAT format.
Verification allows display of LIS or DLIS file content to identify arrays prior to loading.
Depth sampling - .1524000 M 6.0in Ft: BDQC 1 |
Depth sampling - .0025400 M 0.1in:
1A 1 | EV 1 | BA28 1 | BA17 1 | BB17 1 | BC13 1 | BD13 1 | BB28 1 | BA13 1 | BB13 1 | BC17 1 | BD17 1 | BA22 1 | BA23 1 | BA24 1 | BC28 1 | BA25 1 | BA26 1 | BA27 1 | BA11 1 | BA12 1 | BA14 1 | BA15 1 | BA16 1 | BA18 1 | BA21 1 | BC11 1 | BC12 1 | BC14 1 | BC15 1 | BC16 1 | BC18 1 | BC21 1 | BC22 1 | BC23 1 | BC24 1 | BC25 1 | BC26 1 | BC27 1 | BB22 1 | BB23 1 | BB24 1 | BD28 1 | BB25 1 | BB26 1 | BB27 1 | BB11 1 | BB12 1 | BB14 1 | BB15 1 | BB16 1 | BB18 1 | BB21 1 | BD11 1 | BD12 1 | BD14 1 | BD15 1 | BD16 1 | BD18 1 | BD21 1 | BD22 1 | BD23 1 | BD24 1 | BD25 1 | BD26 1 | BD27 1 | SB1 1 | DB1 1 | DB2 1 | DB3A 1 | DB4A 1 | SB2 1 | DB1A 1 | DB2A 1 | DB3 1 | DB4 1 | FCAX 1 | FCAY 1 | FCAZ 1 | FTIM 1 |
Depth sampling - .0381000 M 1.5in:
2A 1 | C1 1 | C2 1 | DCHV 1 | VGAZ 1 | MX1Z 1 | MX2Z 1 | MX3Z 1 | MX4Z 1 | MX5Z 1 | RC1 1 | RC2 1 | PP 1 | CP 1 | AX 1 | AY 1 | AZ 1 | EI 1 | FX 1 | FY 1 | FZ 1 |
TABLE 1
A typical content listing of a DLIS FMS log.
Note:
1. 3 different channel speeds (6.0, 1.5 and 0.1 inches)
2. Buttons of the FMS are individually identified from BA11 to BD27
•
1st Letter B = Button•
2nd Letter A - D = Pad ID (1 - 4)•
1st Number = Row number (1 or 2)•
2nd Number = Button number (from 1 - 8)PETROLOG looks for the 1st value of each array and expects the following buttons to be stored sequentially; therefore it is important to
21
3- Load FMS Image Data
From the DLIS module, select Sub menu 11: DLIS to DAT and select the file to download.
Figure 12
Note:
in the above figure the FMS buttons are saved individually and not as arrays. Sort logs by clicking on the Sort button on the bottom left of the screen to obtain the following;Figure 13 Sorted FMS buttons
Select buttons in the correct order by clicking and dragging the mouse, starting at BA11 and finishing at BD28.
4- Load SHDT Data
Most FMS & FMI data sets include SHDT data recorded as DB1, DB1A, DB2, DB2A, DB3, DB3A, DB4, DB4A
Optional: to run a third party auto dip extractor, it is recommended loading the extra 8 readings, in addition to the image logs.
Alternatively use the BD12 = DB1, DB17=DB1A (repeat for all pads) to process these results.
Once all curves have been selected:
• Click Proceed after selecting all arrays and curves to return to the previous menu.
• Ensure the destination is a new DAT file. The default output filename is the same as the DLIS or LIS file but with a .DAT extension. • Before creating the .DAT file PETROLOG will display the proposed file parameters, as shown below.
Figure 14 The above figure shows the menu that creates a new DAT file.
PETROLOG automatically selects the min-max interval and the number of columns for storage of all arrays and individual logs.
Important Note:
• Increase the number of columns by approximately 15 in order to store Dipmeter results from a third party dip extraction package or Image Processing (Line 1).
• Select only the interval of interest. 100 meters of FMI data will require about 30 Mb in the DAT file (1000m will require 300 Mb) • Change the depth increment on line 4 (see above) to 0.1 inches or fastest channel speed. Do this by clicking in any one
of the Depth Increment boxes.
Click on Proceed and a new file is created with all arrays and logs loaded over the interval selected.
23
FMI DATA IMPORT
1- Copy DLIS or LIS Tape to Hard Disk
2- Create Verification Listing
-FILE ORIGIN - File=FBSTB.072
Run=1
-PARAMETER SUMMARY
Total depth 500.0000 m
-FRAME SUMMARY SPACING (IN,MM) CHANNELS INDEX
1 6.0000000, 152.400 80 BOREHOLE-DEPTH 2 1.0000000, 25.400 14 BOREHOLE-DEPTH 3 .1000000, 2.540 35 BOREHOLE-DEPTH 4 1.5000000, 38.100 10 BOREHOLE-DEPTH
-CHANNEL SUMMARY No. of channels = 139
-FRAME 1
TDEP 1 | BS 1 | CS 1 | TENS 1 | ETIM 1 | DEVI 1 | ANOR 1 | FINC 1 | HAZI 1 | P1AZ 1 | RB 1 | SDEV 1 | GAT 1 | GMT 1 | ITT 1 | SPHI 1 | DCI1 1 | DCI2 1 | DCI4 1 | SOBS 1 | DTCO 1 | DTSM 1 | PR 1 | VPVS 1 | CHR1 1 | DT1R 1 | CHT1 1 | DT1T 1 | CHR2 1 | DT2R 1 | CHT2 1 | DT2T 1 | DTRP 1 | CHRP 1 | DTRS 1 | CHRS 1 | DTTP 1 | CHTP 1 | DTTS 1 | CHTS 1 | DT1 1 | DT2 1 | DT4P 1 | DT4S 1 | CGR 1 | POTA 1 | SGR 1 | THOR 1 | TPRA 1 | TURA 1 | URAN 1 | UPRA 1 | W1NG 1 | W2NG 1 | W3NG 1 | W4NG 1 | W5NG 1 | RSGR 1 | TIME 1 | CVEL 1 | MARK 1 | SAS1 1 | SAS2 1 | SAS4 1 | EI 1 | FNOR 1 | PWF1 4096 | PWN1 8 | PWF2 4096 | PWN2 8 | PWF4 4096 | PWN4 8 | SVEL 1 | SSVE 1 | SPR1 176 | SPT1 176 | SPR2 176 | SPT2 176 | SPR4 101 | SPT4 101 |
-FRAME 2
TDEP 1 | IDWD 1 | SSCD 1 | CDEE 1 | TGST 1 | TSTI 1 | TSCD 1 | TSDG 1 | TIME 1 | SSCV 1 | SSCG 1 | TQCA 1 | TSCV 1 | TQCK 1 |
-FRAME 3
TDEP 1 | TIME 1 | EV 1 | FBGA 1 | DB4A 1 | DB3A 1 | DB2A 1 | DB1A 1 | DB4 1 | DB3 1 | DB2 1 | DB1 1 | FCAX 1 | FCAY 1 | FCAZ 1 | FTIM 1 | AZSNG 1 | AZS1G 1 | FCD4 12 | FCD3 12 | FCD2 12 | FCD1 12 | FCC4 12 | FCC3 12 | FCC2 12 | FCC1 12 | FCB4 12 | FCB3 12 | FCB2 12 | FCB1 12 | FCA4 12 | FCA3 12 | FCA2 12 | FCA1 12 | AZS2G 1 |
-FRAME 4
TDEP 1 | TIME 1 | C1 1 | C2 1 | AX 1 | AY 1 | AZ 1 | FX 1 | FY 1 | FZ 1 |
Minimum depth = 3584.00 FT 1092.40 M Maximum depth = 4414.00 FT 1345.39 M Sequential log data
TABLE 2
A typical DLIS, FMI data set.Note:
the array sizes opposite each of the 139 logs and arrays e.g. FCD4 12There are over 20,000 columns in this file including the 4 sonic waveform arrays each with 4096 values.
3- Select Logs and Arrays
Figure 15 A typical DLIS file containing multiple files (x9) including Super Combo,
FMI and CMR data sets.
Only files 3 and 4 contain FMI data. If in doubt, view the verification listing and check for FCA1 to FCD4 arrays.
Double click in the Logs to Transfer box on the same line as the file you are interested in. This will display all logs available in that file.
Figure 16 Typical FMI logs that have been recorded simultaneously with a NGT tool.
Note:
duplication of curves:• TIME and FTIM (always use the fast channel FTIM in preference) • CS and CVEL (cable speed)
• AX and FCAX, AY and FCAY, AZ and FCAZ. Fast channel FCAX, FCAY, FCAZ should be used in preference to the slow channel speed AX, AY, AZ.
Import the data making sure you change the depth increment to the fast channel speed and add a few empty columns to store interpretation results.
25
OBMI DATA IMPORT
4- Copy DLIS or LIS Tape to Hard Disk
5- Create Verification Listing
Figure 17 A typical DLIS, OBMI data set.
Note:
the array sizes opposite each of the 144 logs and arrays6- Select Logs and Arrays
Figure 18
Select required curves and deselect duplicated curves. Import the data ensuring the depth increment reflects the fast channel speed and add a few empty columns to store interpretation results.
27
EMI DATA IMPORT
1-
Copy LIS or DLIS tape to Hard Disk
Halliburton EMI will normally be on tape in LIS format or CD-ROM in Atlas TIF with file extension .NTI.
2-
Create Verification Listing
-DATA FORMAT SPECIFICATION RECORD Depth log - DEPT M
Absent value = -999.250
Depth sampling - .1000000 M :
DEPT 1 | TENS 1 | MMRK 1 | MINM 1 | CS 1 | ETIM 1 |
Depth sampling - .0250000 M : SACZ 1 | Depth sampling - .0025000 M : FACZ 1 | DXTM 1 | Depth sampling - .0250000 M : RGR 1 | Depth sampling - .1000000 M :
GRU 1 | STAB 1 | AMER 1 | SPEL 256 | SPEH 256 | LSPD 1 | SWPO 1 | Depth sampling - .0250000 M : FRCT 1 | ATIM 1 | Depth sampling - .1000000 M : CCL 1 | DERR 1 | TOID 1 | Depth sampling - .0025000 M :
PAD1 25 | PAD2 25 | PAD3 25 | PAD4 25 | PAD5 25 | PAD6 25 |
Depth sampling - .1000000 M :
EMIM 1 | ACXU 1 | ACYU 1 | ACZU 1 | MGXU 1 | MGYU 1 | MGZU 1 | EMMR 1 | EMMX 1 | DLOD 1 | PLOC 1 | D4IN 1 | GR 1 | GRCO 1 | POTA 1 | URAN 1 | THOR 1 | GRHI 1 | GRTO 1 | GKUT 1 | GRKT 1 | GRTH 1 | SRAT 1 | AMCR 1 | ERPO 1 | ERUR 1 | ERTH 1 | SRCF 1 | NOIS 1 | FERR 1 | LITR 1 | CASR 1 | GRKC 1 | TKRT 1 | UKRT 1 | TURT 1 | GRUR 1 | GRK 1 | GKCL 1 | ATI1 1 | FAVG 1 | NAVG 1 | FTIM 1 | FRMI 1 | CSPC 512 |
Depth sampling - .0025000 M : PADS 200 |
Depth sampling - .1000000 M :
ACCQ 1 | ACCX 1 | ACCY 1 | ACCZ 1 |
Depth sampling - .0025000 M :
ZACC 1 | ZAC2 1 | DXT1 1 | DXT2 1 |
Depth sampling - .1000000 M :
MAGQ 1 | MAGX 1 | MAGY 1 | MAGZ 1 | DEVI 1 | HAZI 1 | AZI1 1 | RB 1 | TEMP 1 | LOWS 1 | CALA 1 | DMIN 1 | DMAX 1 | CAL1 1 | CAL2 1 | CAL3 1 | CAL4 1 | CAL5 1 | CAL6 1 | C14 1 | C25 1 | C36 1 | DCAL 1 | BHVT 1 | AHVT 1 | BHV 1 | AHV 1 | PRES 1 | RAD1 1 | RAD2 1 | RAD3 1 | RAD4 1 | RAD5 1 | RAD6 1 | P1B1 1 | P2B1 1 | P3B1 1 | P4B1 1 | P5B1 1 | P6B1 1 | RHOA 1 | RHOC 1 | PDDV 1 | ITMP 1 |
Depth sampling - .0025000 M :
F1B1 1 | F2B1 1 | F3B1 1 | F4B1 1 | F5B1 1 | F6B1 1 | EDD1 1 | EDD2 1 | EDD3 1 | EDD4 1 | EDD5 1 | EDD6 1 | ERD1 1 | ERD2 1 | ERD3 1 | ERD4 1 | ERD5 1 | ERD6 1 |
Depth sampling - .1000000 M : INCL 1 |
TABLE 3
A typical Halliburton tape verification wiith EMI data set.
PRE-processed array.
The array of 200 values called PADS represent all buttons joined together and depth shifted so that Button 1 of 200 is facing north. The extra 50 button values are null values inserted between pads to give pad separation.
We do not recommend using this pre-processed array for the following reasons:
• Arm swing corrections have not been applied
• Separation between pads is fixed and does not account for hole ovality resulting in variable pad distance • Dynamic corrections cannot be applied on a per pad basis
• Vertical button calibration cannot be applied on a per pad basis
• You cannot run some automated third party dipmeter packages on this array
3-
Select Logs and Arrays
Figure 19 A typical EMI log.
All appropriate logs and arrays are automatically selected by PETROLOG however there is much redundancy e.g.
• CAL1-6 and RAD1-6
• C14 = Rad1+Rad4 (same for C25 and C36) • CALA = Average Caliper.
In preference PETROLOG uses CAL1 to CAL6, however RAD values will work equally well. If radii columns are used, ensure that the mnemonic starts with R… in order for PETROLOG to process the data correctly. Some third party Dipmeter packages only use RAD.
Proceed and make sure to add approximately 15 empty file columns and select the fastest channel speed depth increment before creating the DAT file .
29
STAR DATA IMPORT
1-
Copy LIS or DLIS tape to the Hard Disk
The Western Atlas STAR data set will normally be on tape in LIS format or on a CD-ROM in Atlas TIF with the file extension .TAP
2-
Create a Verification Listing
Depth sampling - .0762000 M: DEPT 1 | GR 1 |
-DATA RECORDS
Depth range = 2328.3672 475.7166 M
- LOG LOG LOG START STOP DEPTH PERC MIN MAX MEAN - NO MNEM UNIT DEPTH DEPTH INC FULL VALUE VALUE VALUE
1 DEPT M 2328.367 475.7166 .0762 100 475.7166 2328.367 1402.042 2 GR GAPI 2309.469 477.8503 .0762 99 39.4102 234.196 119.9977
-FILE TRAILER - LIS.001 Max.Block= 1024 -FILE MARK
-FILE HEADER 2 - LIS.002 Max.Block= 1024
-DATA FORMAT SPECIFICATION RECORD Depth log - DEPT M
Depth sampling - .0050800 M :
DEPT 1 | AZ 1 | DAZ 1 | DEV 1 | ETMD 1 | GAZF 1 | QA 1 | QM 1 | RB 1 |
-DATA RECORDS
.00508 98 0 359.9017 191.8624
-FILE TRAILER - LIS.002 Max.Block= 1024 -FILE MARK
-FILE HEADER 3 - LIS.003 Max.Block= 1024 -DATA FORMAT SPECIFICATION RECORD Depth log - DEPT M
Depth sampling - .0025400 M :
DEPT 1 | BIT 1 | BKRG 1 | CAL1 1 | CAL2 1 | CAL3 1 | DIP1 1 | DIP2 1 | DIP3 1 | DIP4 1 | DIP5 1 | DIP6 1 | GG01 1 | P1BT 24 | P2BT 24 | P3BT 24 | P4BT 24 | P5BT 24 | P6BT 24 | PADG 1 | PD6G 6 | RAD1 1 | RAD2 1 | RAD3 1 | RAD4 1 | RAD5 1 | RAD6 1 | SPD 1 | TEN 1 | TTEN 1 |
TABLE 4
A typical Atlas field tape.Note:
different channel speed logs are stored in different files and you must therefore select the logs from each of these files to make a complete data set.3-
Select Logs and Arrays
Figure 20 The above figure shows log selection.
Note:
this file does not contain AY and AZ to compute speed corrections.Figure 21 A typical Atlas STAR fast channel set (in file #3) and logs and arrays
required for loading.
The GG01 log is the Guard Gain for Pad 1. Load this to apply Emex current corrections to all buttons stored in arrays P1BT to P6BT.
PRE-processed array
Atlas can also supply pre-processed results in two arrays called AMPS and AMPD with: AMP = Amplitude
S = Static
D = Dynamic
Both these arrays are 200 wide. The extra 56 button values are null values inserted between the pads to give pad separation. CDP do not recommend using the pre-processed array for the following reasons:
a. Arm swing corrections may not have been applied
b. The separation between the pads is fixed and does not take into account the hole ovality (variable distance between the pads)
31
CBIL/UBI/USI/AST/SAS/DMT-BHTV DATA IMPORT
UBI and USI are Schlumberger tools AST and SAS are Reeves tools
The same data loading procedures apply to all Sonic Image or BHTV tools currently on the market.
1-
Copy LIS or DLIS tape to the Hard Disk
Use PETROLOG LIS or DLIS modules.
2-
Make a verification listing
-FRAME SUMMARY SPACING (IN,MM) CHANNELS INDEX
1 6.0000000, 152.400 107 BOREHOLE-DEPTH 2 .4000000, 10.160 18 BOREHOLE-DEPTH 3 1.5000000, 38.100 8 BOREHOLE-DEPTH 4 .1000000, 2.540 9 BOREHOLE-DEPTH 5 1.0000000, 25.400 21 BOREHOLE-DEPTH 6 2.0000000, 50.800 13 BOREHOLE-DEPTH
-CHANNEL SUMMARY No. of channels = 176
-FRAME 1
TDEP 1 | BS 1 | CS 1 | TENS 1 | ETIM 1 | FCD 1 | HDAR 1 | CFVL 1 | UPAZ 1 | UBRB 1 | UBAZ 1 | ANOR 1 | FINC 1 | HAZI 1 | P1AZ 1 | RB 1 | SDEV 1 | SDEVM 1 | HAZIM 1 | RB_GPIT 1 | P1AZ_GPI 1 | GAT 1 | GMT 1 | HV 1 | CTEM 1 | HTEN 1 | MRES 1 | DTEM 1 | RMTE 1 | MTEM 1 | AMTE 1 | BDQC 1 | DRHO 1 | DALP 1 | LSRH 1 | LURH 1 | PEF 1 | QRLS 1 | QLS 1 | QRSS 1 | QSS 1 | RHOB 1 | S1RH 1 | NRHO 1 | RLL 1 | RLU 1 | RLS 1 | RLIT 1 | RLLL 1 | RLUL 1 | RLLU 1 | RLUU 1 | LSHV 1 | FFLS 1 | RSS1 1 | RSS2 1 | RSLL 1 | RSUL 1 | RSLU 1 | RSUU 1 | SSHV 1 | FFSS 1 | RCAL 1 | LL 1 | LU 1 | LS 1 | LITH 1 | LLL 1 | LUL 1 | LLU 1 | LUU 1 | SS1 1 | SS2 1 | SLL 1 | SUL 1 | SLU 1 | SUU 1 | CALI 1 | RGCN 1 | DRTA 1 | TALP 1 | RTNR 1 | RCNT 1 | RCFT 1 | CNTC 1 | TNRA 1 | CFTC 1 | RGR 1 | TIME 1 | CVEL 1 | MARK 1 | STIA 1 | STIT 1 | AREA 1 | AFCD 1 | ABS 1 | IHV 1 | ICV 1 | FNOR 1 | DPHI 1 | PHND 1 | TNPH 1 | NPHI 1 | NPL 1 | NPOR 1 | SCNL 1 | GR 1 |
-FRAME 2
TDEP 1 | TIME 1 | GNA1 1 | TTA1 1 | UCLI 1 | BAMN 1 | BAMX 1 | RCMX 1 | RCMN 1 | RCAV 1 | FTED 1 | FT25 1 | FT75 1 | AAAG 45 | A3G 180 | AWBK 180 | TTBK 180 | RSAV 1 |
-FRAME 3
TDEP 1 | AX 1 | AY 1 | AZ 1 | TIME 1 | FX 1 | FY 1 | FZ 1 |
-FRAME 4
TDEP 1 | FCAX 1 | FCAY 1 | FCAZ 1 | FTIM 1 | TDEP 1 | HDRH 1 | HDAL 1 | HPEF 1 | HRHO 1 | HNRH 1 | RHLL 1 | RHLU 1 | RHLS 1 | RHLI 1 | RHS1 1 | RHS2 1 | HLL 1 | HLU 1 | HLS 1 | HLIT 1 | HSS1 1 | TIME 1 | HDPH 1 | HPHN 1 | HSS2 1 | -FRAME 6 TDEP 1 | RGHN 1 | HDRT 1 | HTAL 1 | RHNT 1 | RHFT 1 | HCNT 1 | HCFT 1 | RHGR 1 | TIME 1 | HTNP 1 | HNPO 1 | HGR 1 | Minimum depth = 13329.00 FT 4062.68 M Maximum depth = 13573.50 FT 4137.20 M
TABLE 5
A typical DLIS format, UBI filePETROLOG will automatically identify the required slow channel logs. Identify array logs with 160 or 180 values to identify the name of the Sonic Image to download.
The AWBM and TTBK (Amplitude and Transit Time) are the arrays required from the above example.
3-
Select Logs and Arrays
Figure 22 A typical UBI set of logs and arrays for download with the LDT
simultaneously recorded.
Note:
both slow channel and fast channel accelerometer data is recorded. Preferably use FCAX to Z, fast channel FTIM in preference to slow channel TIME or ETIM.FT25 is the computed caliper at 90 degrees from pad 1 FT75 is the computer caliper at 270 deg from pad 1 FTED is average of FT25 and FT75
PETROLOG can compute 6 radii from the TTBK array thus giving a better estimate of hole ovality and improved dip accuracy. You are now ready to go to PRE-PROCESSING.
Note:
when the CBIL tool is put together it is not always physically orientated to North. The engineer will record the difference in angle of measurement and this is shown in the RBOF (Tool Body Mark Orientation Offset) curve. To correctly orientate the CBIL image, in the Pad Image Menu, Line 7, enter the Magnetic Declination+RBOF. Alternatively you could use Log Manipulation from the Main Menu to create a new corrected HAZI. Using HAZI corrected = AZI-RBOF and then only enter the Magnetic Declination in the Pad Image Menu. If the RBOF curve is missing or recorded as 0.0 then the difference in angle has possibly not been measured and the image will not be properly orientated. In this case, compare the CBIL results with the Microscanner (STAR) logs, if available.33
Mining Logging Contractor DATA IMPORT
PETROLOG has the ability to process a variety of mining company formats. The software to actually decode the raw acquisition files is unstable and will not be released as the formats in the mining industry do vary. Some of the formats we are currently capable of translating are:
1. Robertson Geologging – LGX, VDL,LOG formats 2. Century - .LOG format
3. ALT – CSV and RGB optical image formats
To translate this data, the data should be sent to Crocker Data Processing for translation to universally accepted LIS, DLIS or LAS format.
2- Robertson Geologging Australia
The Robertson Geologging acoustic images are usually encoded with respect to either magnetic North or true North. True North in the mining sense could be geographic north or more rarely mine grid North. This information can be deduced from the HED file that is part of the Robertson Geologging format. The HED file contains a magnetic declination offset that is entered as a positive or negative value. Positive is clockwise rotation from magnetic North and negative is anti-clockwise from Magnetic North. This value can be seen in a typical header file illustrated in Figure 22.
Figure 22 A typical Robertson Geologging HED file.
The curves that contain the data in the Robertson LGX file are as follows:
• Time Time logging
• SHAN Pad one azimuth (the angle of first sample from tool reference mark
• BLNK Blanking period
• PEAK Peak detect period
• GAIN Signal Gain
• RESO Resolution (note – Robertson tool has variable spin rate which affects vertical resolution)
• STEP Head Step
• BAUD Baud Divisor
• PULS Communication Pulse Rate
• N/U N/U • HX Magnetometer x axis • GX Accelerometer x axis • HY Magnetometer y axis • GY Accelerometer y axis • HZ Magnetometer z axis • GZ Accelerometer z axis
• NGAM Natural Gamma
• GLCK- Gamma Timer
• TTEM Transducer Temperature
• PTEM PCB Temperature
• SCAN_AMP
The data curves are seen in Figure 23 below:
Figure 23 A typical Crocker Data Processing translation data set..
3- Century
The Century acoustic televiewer data is contained in one file suffixed “.LGX” This file has the following curves located within the file:
• CAL1 Acoustically computed caliper TIM1-TIM3 axis • CAL2 Acoustically computed caliper TIM2-TIM4 axis • SANG (translated DEVI) Borehole deviation • SANGB(translated HAZI) Borehole Azimuth • PAD1-AZ(translated P1AZ) Azimuth of the first sample • FGAIN(N) Gain value
• TIM1 TIM 1,2,3,4 are orthogonally oriented transit times used to compute the calipers • AMP1 AMP1,2,3,4 are orthogonally oriented amplitudes and can be used in Autodip • TIM2 • AMP2 • TIM3 • AMP3 • TIM4 • AMP4
• TEMP Temperature of the tool • TT Transit time image • AMPS Amplitude
35
MWD Image Tools
In recent years MWD or LWD logging has advanced to include circumferential borehole imaging. Some examples of tools available that provide images that permit interpretation to be undertaken include:
Schlumberger
♦ RAB (Resistivity at bit)
♦ ADN (Azimuthal Density Neutron)
Baker Hughes Inteq
♦ APLS (Azimuthal Density) which will also be capable of azimuthal ultrasonic image
PETROLOG has the ability to process all these tools however Crocker Data Processing Pty Ltd has only seen a few. This section will illustrate the procedure that is necessary to load these data sets.
1- Schlumberger RAB (Resistivity at Bit)
This tool provides a resistivity image at the bit. The tool provides a shallow and deep image of the formation. It can be used to provide an effective structural dip interpretation in horizontal wells (where it has large usage). The data is also used in conventional log analysis and geosteering where the depth of investigation allows contacts, shale stringers and other permeability barriers above and below the tool. The configuration of the tool is illustrated below:
Figure 23 The SLB RAB Tool
2- Schlumberger ADN (Azimuthal Density Neutron)
This tool provides images of density, photo electric effect and neutron at the bit. The density is the most sensitive measurement and produces the best images for effective structural dip interpretation in horizontal wells.
Figure 23 The SLB ADN Tool
Figure 23 The SLB ADN Tool Results
3- Baker Hughes APLS (Azimuthal Density Neutron)
Baker Hughes Inteq has an APLS tool which is similar to the Schlumberger ADN tool. In that it provides a full bore image for interpretation. The specifics of the tool were not primarily for this purpose but as a way of providing accurate density measurements that are oriented in the borehole. Such measurements are necessary if formations above and below a borehole are to be distinguished. The literature from Baker Hughes Inteq, gives the impression that it is designed to provide accurate density measurements based on a binning system. The tool will bin the density measurements into 5 bins based on the distance of the formation from the tool.
Figure 23 Baker Hughes Inteq APLS Binning arrangement
37
PRE-PROCESSING
1-
Add DIPI, AZI, DIPS, and DIPQ Log Names to the Data File
Manually input these 4 new traces or automatically add when editing dips. These output curves are required to save results when extracting dips from the image.
•
DIPI: Dip computed from Images (FMS, FMI, EMI, STAR, BHTV, UBI, etc.)•
AZI: Dip Azimuth relative to North•
DIPS: Dip Status as defined by the interpreter e.g. Stratigraphy, Fault, Unconformity•
DIPQ: Dip Quality or any other dip parameter that can be user defined This information is required for plotting correct vertical displacement of the image sinusoid.Dip calculations are complex; the process starts with screen digitisation of the displayed Image using any three points of an image feature. The points are translated as XYZ coordinates on the borehole periphery and the formation plane can then be shown as dip and azimuth. Because PETROLOG calculates hole diameter for every reading or pad button, the resulting dip sinusoid will reflect hole ovality and may be irregularly shaped.
To add these 4 new logs:
1. Main Menu select 12 Log Manipulation
2. Select 17: Change Log or Unit Names to obtain a screen similar to that shown below.
Figure 24 The above menu shows the additional 4 new curves, DIPI, AZI, DIPD, DIPS
inserted into an FMI data set.
3. Go to end of file and add four new curves called DIPI, AZI, and DIPS (see above).
4. Rename C1 & C2 to CAL1 & CAL2 (C1 and C2 are mnemonics used in PETROLOG as gas chromatograph logs).
IMPORTANT:
these 4 curves will store the manual dips selected from the images. Multiple sets of these curves can be created to save different interpretation sets.2-
Normalize Log Names and Units
In order to standardize the long log names and the units;
• Click on Add Default Long Names to add missing long log names. • Click on Normalize Units to correct spelling and standardize units.
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Interpolate Missing Values (Slow Channel Speed logs)
From the Main Menu select 12: Log Manipulation Select Line 1: Display Log Data
Click Proceed and select ALL to view all logs. Notice slow channels are recorded every 6 inches and Image buttons every 0.1 inch. To plot continuous traces and compute results correctly the slow channel readings need interpolating so that they are continuous traces without gaps as indicated in the following figure;
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Note that the LWD curves shown above are sampled at 0.1m and the Mudlog at 0.5m. The Mudlog needs interpolating. It is important for the software to be able to display the slow channel speed logs as continuous vector traces.
Note:
Combinations of Linear and Special Interpolation (for degrees) are required. For example, the interpolated value between 359 and 3 is not 181 but 1 degree. Clicking on Option 7 (below) will change the interpolation operation from manual (user defined) to automatic (Petrolog defined) interpolation based on log names and units.a) Exit Display Logs and select item Line: 14 Interpolate Missing Values in Log Manipulation module. b) Click on line 7 to change from Manual to Auto.
Figure 26 The Main Menu for interpolating “null values” in a file.
Click on line 7 and PETROLOG will do the following:
c) Scan the file and automatically identify log columns with null values.
d) Group these columns by channel speed (e.g. 2-inch, 3-inch and 6-inch increments).
e) PETROLOG will then show selected logs requiring interpolation.
The following logs and their equivalent names will not be interpolated
• DIP (Truedip, DPTR, DIPF and other equivalent names) • DIPQ (Grad, CQ, QUAF, DIPS and other equivalent names) • DPAZ (DIR, AZIF, AZI and other equivalent names)
These are computed results and not field recorded slow-channel data sets therefore do not require interpolation.
