LAS Digital Well Log Curves

Specification Guidelines

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The entire wellbore system is validated to ensure accuracy of the well information provided such as API/UWI number, orginal operator, well name and well number. The following information is provided with qualifiers: locations, elevations, depths, dates. An H-diagram of the well system is provided for each licensed LAS

Curve Type	Range
Delta	DT, DTL...

An LAS file created from original digital data recorded at the well head (“truck data”), or digitized from images, that typically includes as a minimum and where available, the following curves: gamma ray, spontaneous potential, caliper, resistivity (shallow, medium and deep), sonic and density (bulk, correction, and neutron/density porosity, PE). In addition, operator reported formation tops will be provided where included in the original digital data
Additional logs such as micro logs, dipmeter and other tools, are considered non-standard but may be offered upon request for an additional charge
Mud logs (lithology log, strip log, sample log) are available separately as LAS files. See your account manager for details

Where available three curves from a resistivity log will be processed, typically "shallow, medium, and deep resistivity"

Curve Type	Range	Example	Comments
Shallow	10", 20"	ASN, AT10, ASFL
Medium	30"	ILM, AT30
Deep	60", 90"	ILD, AT90	60" of most continuous
Deep (lateral)	8', 18'	LAT	Digitize all lateral curves

Curve Type	Digitizing Priority #
	Most Continuous	Res	FDC / CNL	Sonic
Gamma Ray "GR"	1	4	2	3	1- Digitize the most continuous curve. 2- Infill missing data from next priority log.
Caliper "CALI"	1	4	2	3	Same as above
Spontaneous Potential SP	1	2	4	3	Same as above

1. Data processed from images:

Data values below first reading will be removed during digitizing
Data values in casing will be removed during digitizing , except radioactive curves: (GR, NEUT, NPOR, SIGMA, ect)
-999.25 will be inserted for all removed data values
Negative values on resistivity will be set at .0004
Negative values on GR will be clipped to 0
Negative values on DT will be clipped to 0
Curves with the same curve name/description will be merged into one continuous curve covering the entire depth available, and curves with different names (eg. AIT 90, AOI 90) will not be merged
In case of overlapping runs, shallower runs first reading will be merged to subsequent deeper runs
All processed curves will retain the original logging contractor mnemonics
Header information will be captured for the last run
All LAS are subject to a rigorous quality control process to provide both complete curve coverage and a match between the digits and the image
With direct correlation, curves such as DPHI and RHOB, and resistivity and conductivity, are overlaid to ensure acccurate digitizing

2. Data processed from digital data:

Curves with the same curve name/description will be spliced into one continues curve covering the entire logged depth available
In case of overlapping runs a mid point between the logging runs will be used to splice the curves
All processed curves will retain the original logging contractor mnemonics
Header data will be preserved, including operator formation tops where available
Minimal processing of the curve data is applied to preserve as much original data as possible
Multiple data files for a single well will be merged into a single LAS file for easier data handling

LAS file will be output in LAS version 2.0
All standard resolution LAS data will be output at depth increments of 0.5 ft for imperial and 0.1 m for metric
TVD curve data, as available may be added as a separate file for an additional charge
High resolution curve data, identified as sampled at less than .1m, may be offered as a separate file where available for an additional charge
Log header parameters and information will be provided in the LAS file for the last run available
Data delivery is available via R360™, FTP, or CD

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