LAS Format

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 and containing minimal header information. The LAS format has evolved over the years. GeoSyn currently supports the import of two versions, 1.2 and 2.0.

GeoSyn will read an attached tops file, although strictly speaking tops are not included in the official LAS format. Two styles of tops formats are supported in Version 2.0, and one format is supported in Version 1.2.

Truncated Example of LAS Version 2.0 Truncated Example of LAS Version 1.2
~VERSION INFORMATION
VERS. 2.00:CWLS LOG ASCII STANDARD - VERSION 2.00
WRAP. NO :One Line per depth step
#
~WELL INFORMATION
#MNEM.UNIT DATA DESCRIPTION
#--------- ----------------------------------- ------------------------------
STRT.M 249.7836 :START DEPTH
STOP.M 1254.2520 :STOP DEPTH
STEP.M 0.1520 :STEP LENGTH
NULL. -999.2500 :NULL VALUE
COMP. AnyCompany OIL & GAS LIMITED :COMPANY
WELL. AnyCompany etal AnyWhere :WELL
LOC . AnyWhere :LOCATION
#
~CURVE INFORMATION
#MNEM.UNIT DATA DESCRIPTION
#--------- ----------------------------------- ------------------------------
DEPT.M :1 Depth
DT .US/M 7 520 80 00 :2 Sonic Travel Time
RHOB.G/C3 31 350 02 00 :3 Bulk Density
#
~PARAMETER INFORMATION
#MNEM.UNIT DATA DESCRIPTION
#--------- ----------------------------------- ------------------------------
EKB .M 300.0000 :Kelly bushing
#
~t 7 Tops //or ~T 7 Tops
T0 647.98
T1 800.89
T2 1011.86
Wabamun 1132.40
Ireton 1536.64
Slave Point 1812.01
Pre Cambrian 1841.80
#
~A DEPT DT RHOB
249.7836 410.825 1819.972
249.9356 410.752 1791.029
250.0876 410.679 1802.005
250.2396 410.607 1869.852
250.3916 410.534 1908.247
250.5436 410.461 1958.225
250.6956 410.388 1987.873
250.8476 410.316 2014.986
250.9996 410.249 2022.811
...
1253.4396 169.758 2730.646
1253.5916 169.758 2730.646
1253.7436 169.758 2730.646
1253.8956 169.758 2730.646
1254.0476 169.758 2730.646
1254.1996 58.382 939.106
No special end of file characters are required.
**alternate tops format
~Formation Tops Information
#TOPS NAME . DEPTH:
BR . 7221.0410:
WPBI . 8034.6790:
COLO . 8539.9220:
CARD . 9553.6900:
CARD . 9671.7980:
L CA . 9743.9760:
BKST . 9799.7500:
~Version : LASOUT vs 1.20
VERS. 1.20: CWLS Log ASCII Standard -VERSION 1.20
WRAP. NO: One line per depth step
~Well Information Block
#MNEM.UNIT Data Type Information
#----.---- ------------: ------------------------------
STRT.M 250.0000: Start Depth
STOP.M 2413.0000: End Depth
STEP.M .2000: Depth Increment
NULL. -999.25:
COMP. COMPANY:
WELL. WELL: Dog Patch LAKE 5-4
FLD . FIELD: Dog Patch
LOC . LOCATION: 10-10-99-1w6
PROV. PROVINCE: ALBERTA
SRVC. SERVICE COMPANY: FlyByNight Loggers
DATE. LOG DATE: 1889/12/29
UWI . UNIQUE WELL ID: 0101010101010
~Parameter Information Block
#MNEM.UNIT Value Description
#----.---- ------------: ------------------------------
BHT .DEGF .0000: Bottom Hole Temperature
BS .MM .0000: Bit Size
DFD .0000: Mud Weight (Density)
DFV .0000: Mud Viscosity
DFL . .0000: Mud Fluid Loss
DFPH .0000: Mud pH
RM .OHMM .0000: Mud Resistivity
RMT .DEGF .0000: Mud Resistivity Temperature
RMFS.OHMM .0000: Mud Filtrate Resistivity
RMFT.DEGF .0000: RMF Temperature
RMC .OHMM .0000: Mud Cake Resistivity
RMCT.DEGF .0000: RMC Temperature
EKB .M 987.5000: Elevation Kelly Bushing
EGL .M 982.3000: Elevation Ground Level
~Curve Information Block
#MNEM.UNIT API CODE Curve Description
#----.---- ------------: ------------------------
DEPT.M : 1 DEPTH
DT .USM 60 520 0 1: 2
RHOB.KM3 42 350 1 1: 3
~A Depth DT RHOB
250.0000 376.4800 1922.6000
250.2000 345.2000 1998.4000
250.4000 313.9200 2363.4000
250.6000 282.6400 2512.2000
250.8000 254.4400 2463.2000
251.0000 275.8800 2392.0000
...
2411.2000 -999.2500 2715.9000
2411.4000 -999.2500 2713.9000
2411.6000 -999.2500 2712.4000
2411.8000 -999.2500 2707.2000
2412.0000 -999.2500 2691.0000
2412.2000 -999.2500 2674.8000
2412.4000 -999.2500 2658.6000
2412.6000 -999.2500 2640.7000
2412.8000 -999.2500 2683.4000
2413.0000 -999.2500 2730.9000
No special end of file characters are required.