标准las(Log ASCII Standard)格式文件终极说明
LAS VERSION 2.0 September 25, 1992
A FLOPPY DISK
STANDARD FOR LOG DATA
BY
Canadian Well Logging Society, Floppy Disk Committee
Suite 229, 640 - 5 Avenue, S.W.
Calgary, Alberta T2P 0M6
Canada
ABSTRACT
The Canadian Well Logging Society's Floppy Disk Committee has designed
a standard format for log data on floppy disks. It is known as the LAS
format (Log ASCII Standard). LAS consists of files written in ASCII
containing minimal header information and is intended for optically
presented log curves. Details of the LAS format are described in this
paper.
The purpose of the LAS format is to supply basic digital log data to users
of personal computers in a format that is quick and easy to use.
INTRODUCTION
Log analysts who use personal computers have, in the past, been entering
log data into their machines mainly through a hand digitizing procedure
because most personal computers are unable to handle data from magnetic
tapes. The industry was beginning to address this inefficiency by making
log data available on floppy disks in a variety of formats. It was at this
point that the Canadian Well Logging Society set up the Floppy Disk
Committee to design a standard for log data on floppy disks that would meet
the needs of personal computer users.
Various standards for digital well log data already exist. The LIS format
(Log Information Standard) is one of the more popular standards. A more
complete standard has been designed by the American Petroleum
Institute and is known as the DLIS format (Digital Log Interchange
Standard). Both of these standards are very useful but because of their
completeness, and resulting complexity, they do not address the needs of
most personal computer users.
Users of personal computers have serious space limitations and are normally
only interested in the optically presented curves. They also want to get
this data into their machines quickly and easily. The LAS format addresses
these needs and can be compared to a "Reader's Digest" version of the LIS
or DLIS formats. If more detailed log information is required, then the
LIS or DLIS format should be used. The LAS format is intended to complement
the LIS or DLIS formats as each has its own specific purpose.
GENERAL DESCRIPTION
The LAS format was designed to be easily understood by the user and at the
same time contain enough flags to assist the programmer. The LAS format
must always be written in ASCII. If it is written using a compression
routine, in binary, or in any other form, an executable program must exist
on the floppy disk that will convert the file back to LAS format.
The LAS format consists of files. For example, a repeat section would make
up one file and the main pass another. Each of the file names end in ".LAS"
so that they can be easily recognized. An individual floppy disk must not
contain partial files that continue onto a second floppy disk. Large files
that do not fit on one floppy must be split into two or more files.
Each file consists of numerous sections. These sections are not order
specific except that the last section must always be the data section.
The first section is usually the "VERSION" section containing the version
number of the LAS format and identifies whether the data is in wrap mode.
The "WELL INFORMATION" section contains information on the well name,
location, and the start and stop depths of the data in this file. The
"CURVE INFORMATION" section contains the curve mnemonics, units used, and
the definitions of these mnemonics, in the order that they appear in the
data section. The "PARAMETER" section contains information on parameters
or constants (such as mud resistivities) and is optional. The "OTHER"
section is also optional and contains any other information or comments.
The last section is always the "ASCII LOG DATA" section. Depth values
normally appear in the first column and each column of data must be separated
by a space.
More detailed LAS format specifications can be found in the Appendix.
REFORMAT AND CERTIFY PROGRAMS
To assist users of LAS formatted data, a program was written to modify
LAS files into forms that may be more compatible to the user's needs.
The program called REFORMAT performs the following tasks:
1) Extract a specific depth interval
2) Extract specific curves
3) Reverse depth direction
4) Change sampling interval
5) Convert wrap mode to unwrap mode
6) Scan for non-standard characters which may cause difficulties
in some programs.
7) Convert LAS version 1.2 to version 2.0
The CERTIFY program was designed to verify that files meet the LAS
standard. If the LAS standards are not met, it will identify the errors.
In case of disagreement between this program and the printed LAS standard
document, the document will be deemed to be correct. The CERTIFY program
also includes documentation on the LAS standard.
The REFORMAT and CERTIFY programs were written by Robin Winsor of Gulf
Canada Resources Ltd. in ANSI standard "C" and compiled with a Microsoft
C 5.1 compiler. These programs are not part of the LAS standard.
The author of these programs does not reserve any rights and does not
warrant the program for any specific purpose. An LAS information package
is available for $10.00 through the C.W.L.S. The package includes an
executable form of the REFORMAT and CERTIFY programs, source code for
REFORMAT, and two test LAS files on a 3.5 inch 720K DOS compatible floppy
disk.
The address is as follows:
Canadian Well Logging Society
#229, 640 - 5 Avenue, S.W.
Calgary, Alberta
CANADA T2P 0M6
CONCLUSIONS
The latest version of the LAS standard is version 2.0 which first became
available in September 1992. The CWLS Floppy Disk Committee will continue
to monitor the LAS standard to address problems and make modifications as
required. Feedback concerning the user's likes or dislikes would be greatly
appreciated and should be sent to the CWLS to the attention of the Floppy
Disk Committee.
It is hoped that by creating the LAS, more widespread use will be made
of digital log data.
APPENDICES
Appendix 1 - LAS Format Specifications for Version 2.0
Appendix 2 - Example LAS Files
Appendix 3 - REFORMAT Program
Appendix 4 - CERTIFY Program
Appendix 5 - Updates
APPENDIX 1
LAS FORMAT SPECIFICATIONS FOR VERSION 2.0
PART 1 GENERAL DESCRIPTION
- The LAS Format is designed to store log data on floppy disks. This
standard is intended to simplify the exchange of digital log data between
users. The general specifications of this format are as follows:
- The floppy disk size, type, or density is not specified because
conversion between them is straightforward.
- It is the intent of this standard to store optically presented log
curves although other curves may also be stored. Raw count rates, wave
form data etc. are more efficiently stored on magnetic tape using LIS
or DLIS format.
- Floppy disks in the LAS format must be MS/DOS or PC/DOS compatible
- The file must be written in ASCII. If the file is written using a
compression routine, in binary, or in any other form, an executable program
must exist on the floppy to convert it back to LAS format.
- An individual floppy disk must not contain partial files that continue
onto a second floppy. Large files that do not fit onto one floppy must
be split into two or more separate files. This may be achieved by
splitting the curves or segmenting the depths.
- All files in LAS format must end in ".LAS" so that they may be easily
recognized.
- The LAS format is a minimum standard. It is expected that most users
and suppliers will exceed this minimum standard.
PART 2 MAJOR COMPONENTS OF AN LAS FILE
- Each LAS file contains numerous sections and each section begins with a
tilde (~) mark. The last section in an LAS file must always be the log
data section.
- The sections that make up an LAS file are as follows:
~V - contains version and wrap mode information
~W - contains well identification
~C - contains curve information
~P - contains parameters or constants (this section is optional)
~O - contains other information such as comments (this section is optional)
~A - contains ASCII log data
- These sections are described in more detail in part four of this appendix.
PART 3 FLAGS
Flags are used to assist computers in identifying specific lines in a file.
The following flags are used in the LAS format:
"~" (tilde): The ASCII equivalent of this flag is decimal 126 or hexadecimal
7E. This flag when used will be the first non-space and non-quotation
character on a line. It is used to mark the beginning of a section
in a file. The first letter directly after the tilde identifies
the section. (See part two.) All upper case letters in the space
following a tilde mark are reserved for use by the committee.
The remainder of the line will be treated as comments.
"#" (pound): The ASCII equivalent of this flag is decimal 35 or hexadecimal
23. This flag when used will be the first non-space and non-quotation
character on a line. The pound sign is used to indicate that the
line is a comment line. Comment lines can appear anywhere above the
~A section.
"." and ":" : In the "Version", "Well", "Curve", and Parameter", sections
the dots, colons, and spaces are used to delimit the information
within the line. each non-comment line in these sections must
contain one dot and one colon and have their lines laid out as
follows:
MNEM.UNITS DATA :DESCRIPTION OF MNEMONIC
Where MNEM = mnemonic. This mnemonic can be of any length but must not
contain any internal spaces, dots, or colons. Spaces are permitted
in front of the mnemonic and between the end of the mnemonic and
the dot.
UNITS = units of the mnemonic (if applicable). The units if used,
must be located directly after the dot. There must be no spaces
between the units and the dot. The units can be of any length
but must not contain any colons or internal spaces.
DATA = value of, or data relating to the mnemonic. This value or
input can be of any length and can contain spaces or dots as
appropriate, but must not contain any colons. It must be
preceded by at least one space to demarcate it from the units
and must be to the left of the colon.
DESCRIPTION = description or definition of the mnemonic. It is
always located to the right of the colon. Its length is limited
by the total line length limit of 256 characters which includes
a carriage return and a line feed.
PART 4 DETAILS
The actual format for each of the sections discussed in this part of the
paper is best understood by looking at the examples in the boxed areas.
The exact spacing is not critical because computer programs will use the
dots, colons, and spaces to decipher each line.
~V (Version Information)
-This section is mandatory and usually appears at the very beginning of
the file.
-It identifies which version of the LAS format is being used and whether
wrap mode is used.
-This section must contain the following lines:
"VERS. 2.0 : CWLS LOG ASCII STANDARD - VERSION 2.0"
Refers to which version of LAS was used.
"WRAP. YES : Multiple lines per depth step"
OR
"WRAP. NO : One line per depth step"
Refers to whether a wrap around mode was used in the data section.
If no wrap mode is used the line will have a maximum length of 256
characters (including the carriage return and line feed). If wrap
mode is used the depth value will be on its own line and all lines
of data will be no longer than 80 characters (including carriage
return and line feed).
-Additional lines in the version section are optional.
-The following is an example of a Version Information Section.
-----------------------------------------------------------------------------
~Version Information Section
VERS. 2.0 : CWLS log ASCII Standard -VERSION 2.0
WRAP. NO : One line per depth step
-----------------------------------------------------------------------------
~W (Well Information)
-This section is mandatory.
-It identifies the well, its location and indicates the start and stop
depths of the file.
-This section must contain the following lines with the mnemonics as
indicated:
"STRT.M nnn.nn : START DEPTH"
Refers to the first depth in the file. The "nnn.nn" refers to the
depth value. The number of decimals used is not restricted. The
".M" refers to metres and can be replaced when other units are
used. The start depth can be either greater or less than the stop
depth.
"STOP.M nnn.nn : STOP DEPTH"
Refers to the last depth in the file. The "nnn.nn" refers to the
depth value. The number of decimals used is not restricted. The
".M" refers to metres and can be replaced when other units are
used.
"STEP.M nnn.nn : STEP"
Refers to the depth increment used. A minus sign must precede the
step value if the start depth is greater than the stop depth
(ie, from TD to casing has a minus step value). A step value of
zero indicates a variable step.
"NULL. nnnn.nn : NULL VALUE"
Refers to null values. Two common ones in use are -9999 and -999.25.
"COMP. aaaaaaaaaaaaaaaaaaaaa : COMPANY"
Refers to company name.
"WELL. aaaaaaaaaaaaaaaaaaaaa : WELL"
Refers to the well name.
"FLD. aaaaaaaaaaaaaaaaaaaaa : FIELD"
Refers to the field name.
"LOC. aaaaaaaaaaaaaaaaaaaaa : LOCATION"
Refers to the well location.
"PROV. aaaaaaaaaaaaaaaaaaaaa : PROVINCE"
Refers to the province. For areas outside Canada this line may be
replaced by:
"CNTY. aaaaaaaaaaaaaaaaaaaaa : COUNTY"
"STAT. aaaaaaaaaaaaaaaaaaaaa : STATE"
"CTRY. aaaaaaaaaaaaaaaaaaaaa : COUNTRY"
"SRVC. aaaaaaaaaaaaaaaaaaaaa : SERVICE COMPANY"
Refers to logging company.
"DATE. aaaaaaaaaaaaaaaaaaaaa : DATE"
Refers to date logged.
"UWI . aaaaaaaaaaaaaaaaaaaaa : UNIQUE WELL ID"
Refers to unique well identifier. (See References.) For areas
outside of Canada this may be replaced by:
"API . aaaaaaaaaaaaaaaaaaaaa : API NUMBER"
-Additional lines in the well information section are optional. There is no
limit set on the number of additional lines.
-The following is an example of a Well Information Section in LAS version 2.0:
_____________________________________________________________________
~Well Information Section
#MNEM.UNIT VALUE/NAME DESCRIPTION
#-------- -------------- ---------------------
STRT.M 635.0000 :START DEPTH
STOP.M 400.0000 :STOP DEPTH
STEP.M -0.125 :STEP
NULL. -999.25 :NULL VALUE
COMP. ANY OIL COMPANY INC. :COMPANY
WELL. ANY ET AL 12-34-12-34 :WELL
FLD . WILDCAT :FIELD
LOC . 12-34-12-34W5M :LOCATION
PROV. ALBERTA :PROVINCE
SRVC. ANY LOGGING COMPANY INC. :SERVICE COMPANY
DATE. 13-DEC-86 :LOG DATE
UWI . 100123401234W500 :UNIQUE WELL ID
_____________________________________________________________________
~C (Curve Information)
-This section is mandatory.
-It describes the curve and its units in the order they appear in the
data section of the file.
-The mnemonics used are not restricted but must be defined on the line in
which they appear.
-API codes are optional. (See References.)
-The curves described in this section must be present in the data set.
-The first curve described is normally depth.
- The units mnemonics if used must be directly to the right of the dot. No
spaces must occur between the dot and the units mnemonic.
-The following is an example of a Curve Information Section with API codes.
-----------------------------------------------------------------------------------------------------
~Curve Information Section
#MNEM.UNIT API CODE Curve Description
#---------- ----------- -------------------------------
DEPTH.M : 1 DEPTH
RHOB .K/M3 45 350 02 00 : 2 BULK DENSITY
NPHI .VOL/VO 42 890 00 00 : 3 NEUTRON POROSITY - SANDSTONE
MSFL .OHMM 20 270 01 00 : 4 Rxo RESISTIVITY
SFLA .OHMM 07 222 01 00 : 5 SHALLOW RESISTIVITY
ILM .OHMM 07 120 44 00 : 6 MEDIUM RESISTIVITY
ILD .OHMM 07 120 46 00 : 7 DEEP RESISTIVITY
SP .MV 07 010 01 00 : 8 SPONTANEOUS POTENTIAL
GR .GAPI 45 310 01 00 : 9 GAMMA RAY
CALI .MM 45 280 01 00 : 10 CALIPER
DRHO .K/M3 45 356 01 00 : 11 DENSITY CORRECTION
-------------------------------------------------------------------------------------------------------
~P (Parameter Information)
-This section is optional. It defines the input values of various
parameters relating to this well. These input values can consist of
numbers or words.
-The mnemonics used are not restricted but must be defined on the line on
which they appear.
-There is no limit on the number of lines that can be used.
-The following is an example of a Parameter Information Section.
-----------------------------------------------------------------------------
~Parameter Information Section
#MNEM.UNIT Value Description
#----------------- ------------ ------------------------------
MUD . GEL CHEM : Mud type
BHT .DEG 114.0000 : Bottom Hole Temperature
BS .MM 222.0000 : Bit Size
FD .K/M3 999.9999 : Fluid Density
MDEN.K/M3 2650.0000 : Logging Matrix Density
MATR . SAND : Neutron Matrix
FNUM . 1.0000 : Tortuosity Constant Archie's (a)
FEXP . 2.0000 : Cementation Exponent Archie's (m)
DFD .K/M3 1200.0000 : Mud Weight
DFV .S 50.0000 : Mud Viscosity
DFL .C3 8.0000 : Mud Fluid Loss
DFPH . 10.0000 : Mud pH
RMFS .OHMM 2.8200 : Mud Filtrate Resistivity
EKB .M 566.9700 : Elevation Kelly Bushing
EGL .M 563.6799 : Elevation Ground Level
-----------------------------------------------------------------------------
~O (Other Information)
-This section is optional. It is intended as a remarks or comments section.
-The following is an example of an "Other Information Section"
------------------------------------------------------------------------------------------------------------
~Other Information Section
The log digits for this well were hand digitized from very poor half scale
log prints. This was the best information available at the time. Every
attempt should be made to track down the original films.
.Dec. 12,1990 John Doe, Petrophysics
------------------------------------------------------------------------------------------------------------
~A (ASCII LOG DATA)
-The data section will always be the last section in a file.
-Each column of data must be separated by at least one space.
-A line of less than 256 characters (including a carriage return and line
feed) will normally not be wrapped. Wrap mode will be used if the data is
longer than 256 characters.
-In wrap mode, depth will be on its own line.
-In wrap mode, a line of data will be no longer than 80 characters. This
includes a carriage return and line feed.
-If wrap mode is used, the decimal points should be aligned for ease of
reading.
-Exponents are not permitted. The curve section can be used to overcome
this limitation by changing the units.
REFERENCES
UWI codes : "Formation Water Resistivities of Canada", CWLS, 1987.
API codes : "Recommended Standard Format for Recording Digital Well Log
Data on Magnetic Tape", API - Bul. D-9, 3rd edition, 1981.
APPENDIX 2
EXAMPLE LAS FILES
EXAMPLE #1 - THE LAS STANDARD IN UNWRAPPED MODE
~VERSION INFORMATION
VERS. 2.0 : CWLS LOG ASCII STANDARD -VERSION 2.0
WRAP. NO : ONE LINE PER DEPTH STEP
~WELL INFORMATION
#MNEM.UNIT DATA DESCRIPTION
#----- ----- ---------- -------------------------
STRT .M 1670.0000 :START DEPTH
STOP .M 1660.0000 :STOP DEPTH
STEP .M -0.1250 :STEP
NULL . -999.25 :NULL VALUE
COMP . ANY OIL COMPANY INC. :COMPANY
WELL . ANY ET AL 12-34-12-34 :WELL
FLD . WILDCAT :FIELD
LOC . 12-34-12-34W5M :LOCATION
PROV . ALBERTA :PROVINCE
SRVC . ANY LOGGING COMPANY INC. :SERVICE COMPANY
DATE . 13-DEC-86 :LOG DATE
UWI . 100123401234W500 :UNIQUE WELL ID
~CURVE INFORMATION
#MNEM.UNIT API CODES CURVE DESCRIPTION
#------------------ ------------ -------------------------
DEPT .M : 1 DEPTH
DT .US/M 60 520 32 00 : 2 SONIC TRANSIT TIME
RHOB .K/M3 45 350 01 00 : 3 BULK DENSITY
NPHI .V/V 42 890 00 00 : 4 NEUTRON POROSITY
SFLU .OHMM 07 220 04 00 : 5 SHALLOW RESISTIVITY
SFLA .OHMM 07 222 01 00 : 6 SHALLOW RESISTIVITY
ILM .OHMM 07 120 44 00 : 7 MEDIUM RESISTIVITY
ILD .OHMM 07 120 46 00 : 8 DEEP RESISTIVITY
~PARAMETER INFORMATION
#MNEM.UNIT VALUE DESCRIPTION
#-------------- ---------------- -----------------------------------------------
MUD . GEL CHEM : MUD TYPE
BHT .DEGC 35.5000 : BOTTOM HOLE TEMPERATURE
BS .MM 200.0000 : BIT SIZE
FD .K/M3 1000.0000 : FLUID DENSITY
MATR . SAND : NEUTRON MATRIX
MDEN . 2710.0000 : LOGGING MATRIX DENSITY
RMF .OHMM 0.2160 : MUD FILTRATE RESISTIVITY
DFD .K/M3 1525.0000 : DRILL FLUID DENSITY
~OTHER
Note: The logging tools became stuck at 625 metres causing the data
between 625 metres and 615 metres to be invalid.
~A DEPTH DT RHOB NPHI SFLU SFLA ILM ILD
1670.000 123.450 2550.000 0.450 123.450 123.450 110.200 105.600
1669.875 123.450 2550.000 0.450 123.450 123.450 110.200 105.600
1669.750 123.450 2550.000 0.450 123.450 123.450 110.200 105.600
EXAMPLE #2 - ILLUSTRATING THE LAS STANDARD WITH
MINIMUM HEADER REQUIREMENTS IN UNWRAPPED MODE.
~V
VERS. 2.0 : CWLS log ASCII Standard -VERSION 2.0
WRAP. NO : One line per depth step
~W
STRT.M 635.0000 :START DEPTH
STOP.M 400.0000 :STOP DEPTH
STEP.M -0.1250 :STEP
NULL. -999.25 :NULL VALUE
COMP. ANY OIL COMPANY INC. :COMPANY
WELL. ANY ET AL 12-34-12-34 :WELL
FLD . WILDCAT :FIELD
LOC . 12-34-12-34W5M :LOCATION
PROV. ALBERTA :PROVINCE
SRVC. ANY LOGGING COMPANY INC. :SERVICE COMPANY
DATE. 13-DEC-86 :LOG DATE
UWI . 100123401234W500 :UNIQUE WELL ID
~C
DEPT .M : DEPTH
RHOB .K/M3 : BULK DENSITY
NPHI .VOL/VOL : NEUTRON POROSITY - SANDSTONE
MSFL .OHMM : Rxo RESISTIVITY
SFLA .OHMM : SHALLOW RESISTIVITY
ILM .OHMM : MEDIUM RESISTIVITY
ILD .OHMM : DEEP RESISTIVITY
SP .MV : SPONTANEOUS POTENTIAL
~A
635.0000 2256.0000 0.4033 22.0781 22.0781 20.3438 3.6660 123.4
634.8750 2256.0000 0.4033 22.0781 22.0781 20.3438 3.6660 123.4
EXAMPLE #3 - ILLUSTRATING THE WRAPPED VERSION
OF THE LAS STANDARD
~VERSION INFORMATION
VERS. 2.0 : CWLS log ASCII Standard -VERSION 2.0
WRAP. YES : Multiple lines per depth step
~WELL INFORMATION
#MNEM.UNIT DATA DESCRIPTION
#----- ----- ---------- -----------------------------
STRT .M 910.0000 :START DEPTH
STOP .M 909.5000 :STOP DEPTH
STEP .M -0.1250 :STEP
NULL . -999.25 :NULL VALUE
COMP . ANY OIL COMPANY INC. :COMPANY
WELL . ANY ET AL 12-34-12-34 :WELL
FLD . WILDCAT :FIELD
LOC . 12-34-12-34W5M :LOCATION
PROV . ALBERTA :PROVINCE
SRVC . ANY LOGGING COMPANY INC. :SERVICE COMPANY
SON . 142085 :SERVICE ORDER NUMBER
DATE . 13-DEC-86 :LOG DATE
UWI . 100123401234W500 :UNIQUE WELL ID
~CURVE INFORMATION
#MNEM.UNIT Curve Description
#--------- ------------------------------
DEPT .M : Depth
DT .US/M : 1 Sonic Travel Time
RHOB .K/M : 2 Density-Bulk Density
NPHI .V/V : 3 Porosity -Neutron
RX0 .OHMM : 4 Resistivity -Rxo
RESS .OHMM : 5 Resistivity -Shallow
RESM .OHMM : 6 Resistivity -Medium
RESD .OHMM : 7 Resistivity -Deep
SP .MV : 8 Spon. Potential
GR .GAPI : 9 Gamma Ray
CALI .MM : 10 Caliper
DRHO .K/M3 : 11 Delta-Rho
EATT .DBM : 12 EPT Attenuation
TPL .NS/M : 13 TP -EPT
PEF . : 14 PhotoElectric Factor
FFI .V/V : 15 Porosity -NML FFI
DCAL .MM : 16 Caliper-Differential
RHGF .K/M3 : 17 Density-Formation
RHGA .K/M3 : 18 Density-Apparent
SPBL .MV : 19 Baselined SP
GRC .GAPI : 20 Gamma Ray BHC
PHIA .V/V : 21 Porosity -Apparent
PHID .V/V : 22 Porosity -Density
PHIE .V/V : 23 Porosity -Effective
PHIN .V/V : 24 Porosity -Neut BHC
PHIC .V/V : 25 Porosity -Total HCC
R0 .OHMM : 26 Ro
RWA .OHMM : 27 Rfa
SW . : 28 Sw -Effective
MSI . : 29 Sh Idx -Min
BVW . : 30 BVW
FGAS . : 31 Flag -Gas Index
PIDX . : 32 Prod Idx
FBH . : 33 Flag -Bad Hole
FHCC . : 34 Flag -HC Correction
LSWB . : 35 Flag -Limit SWB
~A Log data section
910.000000
-999.2500 2692.7075 0.3140 19.4086 19.4086 13.1709 12.2681
-1.5010 96.5306 204.7177 30.5822 -999.2500 -999.2500 3.2515
-999.2500 4.7177 3025.0264 3025.0264 -1.5010 93.1378 0.1641
0.0101 0.1641 0.3140 0.1641 11.1397 0.3304 0.9529
0.0000 0.1564 0.0000 11.1397 0.0000 0.0000 0.0000
909.875000
-999.2500 2712.6460 0.2886 23.3987 23.3987 13.6129 12.4744
-1.4720 90.2803 203.1093 18.7566 -999.2500 -999.2500 3.7058
-999.2500 3.1093 3004.6050 3004.6050 -1.4720 86.9078 0.1456
-0.0015 0.1456 0.2886 0.1456 14.1428 0.2646 1.0000
0.0000 0.1456 0.0000 14.1428 0.0000 0.0000 0.0000
909.750000
-999.2500 2692.8137 0.2730 22.5909 22.5909 13.6821 12.6146
-1.4804 89.8492 201.9287 3.1551 -999.2500 -999.2500 4.3124
-999.2500 1.9287 2976.4451 2976.4451 -1.4804 86.3465 0.1435
0.0101 0.1435 0.2730 0.1435 14.5674 0.2598 1.0000
0.0000 0.1435 0.0000 14.5674 0.0000 0.0000 0.0000
909.625000
-999.2500 2644.3650 0.2765 18.4831 18.4831 13.4159 12.6900
-1.5010 93.3999 201.5826 -6.5861 -999.2500 -999.2500 4.3822
-999.2500 1.5826 2955.3528 2955.3528 -1.5010 89.7142 0.1590
0.0384 0.1590 0.2765 0.1590 11.8600 0.3210 0.9667
0.0000 0.1538 0.0000 11.8600 0.0000 0.0000 0.0000
909.500000
-999.2500 2586.2822 0.2996 13.9187 13.9187 12.9195 12.7016
-1.4916 98.1214 201.7126 -4.5574 -999.2500 -999.2500 3.5967
-999.2500 1.7126 2953.5940 2953.5940 -1.4916 94.2670 0.1880
0.0723 0.1880 0.2996 0.1880 8.4863 0.4490 0.8174
0.0000 0.1537 0.0000 8.4863 0.0000 0.0000 0.0000
EXAMPLE # 4 LAS FILE FOR TIME BASED DATA
~VERSION INFORMATION
VERS. 2.0 : CWLS LOG ASCII STANDARD -VERSION 2.0
WRAP. NO : ONE LINE PER TIME STEP
#
~WELL INFORMATION
STRT .S 0.0000 :START TIME
STOP .S 39.9000 :STOP TIME
STEP .S 0.3000 :STEP
NULL . -999.25 :NULL VALUE
COMP . ANY OIL COMPANY INC. :COMPANY
WELL . ANY ET 12-34-12-34 :WELL
FLD . WILDCAT :FIELD
LOC . 12-34-12-34W5 :LOCATION
PROV . ALBERTA :PROVINCE
SRVC . ANY LOGGING COMPANY INC. :SERVICE COMPANY
DATE . 13-DEC-86 :LOG DATE
UWI . 100123401234W500 :UNIQUE WELL ID
#
~CURVE INFORMATION
ETIM .S : 1 ELAPSED TIME
BFR1 .OHMM : 2 SINGLE PROBE 1 RESISTIVITY
BSG1 .PSIG : 3 SINGLE PROBE 1 STRAIN GAUGE PRESSURE
#
~PARAMETER INFORMATION
MRT .DEGC 67.0 : BOTTOM HOLE TEMPERATURE
GDEPT .M 3456.5 : GAUGE DEPTH
DFD .KG/M3 1000.0 : MUD WEIGHT
#
~A
0.0000 0.2125 16564.1445
0.3000 0.2125 16564.1445
0.6000 0.2125 16564.2421
0.9000 0.2125 16564.0434
1.2000 0.2125 16564.0430
1.5000 0.2125 16564.0435
APPENDIX 4
REFORMAT PROGRAM
The REFORMAT program was designed to manipulate LAS formatted files into a
form which may be more compatible with the user's needs. The REFORMAT
program is not part of the LAS standard.
The REFORMAT program is capable of doing the following things:
1) Extract a depth interval
- This allows the user to build a new LAS file covering a specific
depth interval of the input file. It works on unwrapped data only.
2) Extract one or more curves
- This allows the user to build a new LAS file containing only the
curves specified by him. It will handle input data with lines up
to 1200 characters long. It works only on unwrapped data.
3) Reverse depth direction
- Logs can be recorded from bottom to top or visa versa. This
routine reverses the depth direction. It works on unwrapped data
only.
4) Change depth step (i.e. depth increment)
- The depth step refers to the depth increment. This routine works
only on unwrapped data.
5) Convert wrap to unwrap mode
- Wrap mode refers to the mode where the depth value is on its own
line and all of the curve data for that depth value are on the
lines that follow (see TEST02.LAS for an example). Unwrap mode
means there is only one line of curve data for each depth step
and the depth value is the first value in that line. This routine
converts wrapped data to the unwrapped mode provided that the
resulting lines are not longer than 1200 characters.
6) Scan for non-standard characters
- Non ASCII or unprintable characters can cause difficulties to
some programs. This routine allows the user to find them and
delete them.
7) Convert LAS version 1.2 to version 2.0
The REFORMAT program was written in ANSI standard 'C' and has been compiled
with Microsoft C5.1 compiler. The author of the program does not
reserve any rights and does not warrant the program for any
specific purpose. The executable as well as the code for REFORMAT
is included on the enclosed floppy disk.
APPENDIX 5
CERTIFY PROGRAM
The CERTIFY program was designed to read LAS files and establish whether
all of the LAS specifications are being adhered to. This program also
points out where the LAS specifications are not being followed
This program issues two types of messages. One is a "WARNING" and the
other is a "FATAL ERROR". The "WARNING" is used to point out items that
meet the LAS standard but could be improved upon to make the file more
informative to the user. For example, if the "location" field in the Well
Information Section is left blank the CERTIFY program will issue a WARNING.
The "FATAL ERROR" message is issued on items that fail to meet the LAS
specifications. For example if the "location" field is omitted from the
Well Information Section, the CERTIFY program will issue a "FATAL ERROR"
message.
The CERTIFY program is not part of the LAS Standard. It is being made
available to assist the user in locating and identifying the most
commonly occurring errors.
APPENDIX 6
UPDATES
AUGUST 14, 1991
LAS -version 1.2
REFORMAT -version 2.0 (correcting errors in resampling and unwrap options)
CERTIFY -version 1.0
APRIL 22, 1992
LAS -version 1.2
REFORMAT -version 2.0
CERTIFY -version 2.0
MAY 18, 1992
LAS -version 1.2
REFORMAT -version 2.0
CERTIFY -version 3.0 (improve data section checking)
JUNE 8, 1992
LAS -version 1.2
REFORMAT -version 2.1 (fix minor bug in resample. Stop depth set correctly)
CERTIFY -version 3.0
SEPTEMBER 25, 1992
LAS -version 2.0
REFORMAT -version 2.2 (modified to handle LAS v 2.0)
CERTIFY -version 3.1 (modified to handle LAS v 2.0)
MARCH 16, 1993
LAS -version 2.0
REFORMAT -version 2.3 (256 character header allowed when unwrapping)
CERTIFY -version 3.2 (stricter ~ section and line length checks)
JUNE 11, 1993
LAS -version 2.0
REFORMAT -version 2.4 (minor bug fixes)
CERTIFY -version 3.3 (minor bug fixes)
NOVEMBER 7, 1993 (These and later versions require an 80286 processor or better.)
LAS -version 2.0
REFORMAT -version 2.41 (Improved end of file handling, minor bug fix.)
CERTIFY -version 3.4 (Complete data section checking, better end of file
handling and improved error reports.)
MARCH 23, 1994
CERTIFY -version 3.5 (Fatal end of file condition changed to warning. Minor bug fixes.)
Please address any problems to:
CWLS Floppy Disk Committee
Suite 229, 640 - 5 Avenue, S.W.
Calgary, Alberta T2P 0M6
CANADA
