The digital well log data set from USLandGrid is the most comprehensive collection of North Dakota LAS files available on the market today. With over 14,000 individual wells and over 300,000 individual curves, USLandGrid offers companies an easy way to expand their existing coverage, start from scratch for newly acquired acreage, or quickly get down the path on play evaluations.
By working with experienced geologists, USLandGrid delivers a product that can be directly imported into your project without the fear of garbage in-garbage out.
The digital well logs have been meticulously scrutinized to ensure the most accurate assignment of data to the correct original wellbore, sidetrack, and recompletion. Additionally, digital well log data has been separated into measured depth (MD) and true vertical depth (TVD) categories to help avoid unpleasant surprises due to depth issues upon import and interpretation.
Whether you seek to investigate a single field or do a regional study, digital well logs from USLandGrid have you covered in North Dakota.
The LAS files are delivered in 2 different configurations; by logging run and by wellbore. There are over 55k las files in the logging run version and 14k las files in the wellbore version. Both versions contain the same curves and wells. Individual wells have multiple log types per well (CBL, DTSM, etc). In the logging run configuration, the original headers have been preserved and the original runs each have their own las file. In the wellbore configuration, all of the curves for a given well have been saved into a single las file. API numbers have been corrected in both datasets. Header data (aside from API number) in all las files is only as accurate as the original source material from the operator and logging company.
Every reasonable attempt has been made to assign the correct API number to the correct log curve. The majority of these changes has been done manually and involved looking at the original well documentation and geologic reports. Only experienced geologists have performed this work.
Approximately 4% of the original las files are in TVD. Every attempt has been made to separate these files from the MD logs. They are located in their own “TVD Logs” folder. API numbers have been properly assigned to them and they could be accurately imported if desired. However, it is not recommended to use these files unless your software package allows for the proper importation of TVD logs. In most cases, the TVD log covers the curve portion of Bakken/Three Fork wells and is a replication of the existing MD log for the same interval.
The wellbore numbering convention is based on the 14-digit API standard. The last 4 digits in the original wellbore will be 0000. Sidetracks are covered in positions 11 and 12. Recompletes are covered in positions 13 and 14. For example, the first sidetrack of a well will end in 0100 and the second sidetrack will end in 0200. Wells that have been converted from producers to SWD, as another example, will typically be assigned a recomplete designation and end in 0001. This standardized numbering convention is currently used by most major data vendors (IHS, TGS-NOPEC, Drilling Info (end of 2016), etc).
A spreadsheet has been provided to assist in developing a comprehensive log curve mnemonics aliasing list for whatever software package is used for log interpretation or display. In this dataset, there are over 350k log curves with over 7k individual curve names. The provided list of aliases covers ~60% of the curves. Aliasing involves both technical understanding of the logging tools and personal preference. Use at your own risk and modify to your needs.
C1, C2, C3, C4, etc. have NOT been aliased as gas curves. It should be noted that some caliper tool companies use the same mnemonics to describe the reading from each arm of the caliper. When using these curves it is important to pay attention to the original data.
Importing the las files via logging run (52k las files) may result in some errors depending on which software package is being used (Petra, GeoGraphix, Petrel, SMT, etc). A failure rate of up to 2.5% may be expected. This is typically due to non-numeric values in numeric fields within the original las file or unlabeled curve headers and may only impact a single curve within an individual file. There should be close to zero errors importing the las files via wellbore (14k las files).