Version 2.7

Well Log Viewer software can be used for viewing and plotting oilfield well-log data that is stored in either LAS, CSV, JSON or DLIS format files, and seismic waveform data that is stored in LDF or SEG-Y format files.

Some basic processing functionality for both Log data and VSP data is included. 



LAS files are ASCII files that are used to store and share oilfield well-log data. LAS files only support storing log channels that have a single data value at every depth point.

CSV or comma separated value files, are simplified ASCII files that contain only log data, and no other information. The format required for CSV files is specific to this application and discussed in a later section. Similar to LAS files, CSV files only support storing log channels that have a single data value at every depth point.

Log data can also be stored in JSON formatted files. Only JSON files that are written according to the specifications desribed at can be read. JSON files are also an ASCII type file, so can be previewed with Notepad. They additionally support storing single axis array data. Multi-axis array may be supported in future releases.

DLIS files are binary files. See for a full description. DLIS files support a large range of possibilities for data types, that includes multi-axis array data.

LDF and SEG-Y files are used to store seismic waveform data (VSP waveform data).

Some of the Processing functionality that is currently available includes:

  • Unit conversions of log curves
  • Some basic arithmethic functions on log curves.
  • Resampling log curves to different samples rates.
  • Curve cross-plotting and curve fitting.
  • TVD computation from deviation survey, and log TVD conversion.
  • Computions of velocity logs, acoustic impedance, elastic modulii and other geophysical logs.
  • Spatial filtering of logs.
  • V-Shale and V-Clay computations.
  • Porosity computations from NPHI-RHOB logs.
  • Rock Strength computations
  • VSP waveform filtering.
  • Q-estimation of VSP data
  • Synthetic Seismogram.

1.1 Curve Names and Curve Units

An important aspect of loading data is the automatic assignment of Curve Names to Curve Groups, and also the conversion of the Unit Names to standardized nomenclature.

See section 4.7 and 4.8 for more details.

1.2 DLIS to ASCII Converter

A basic use of Well Log Viewer app is simply to use it as a converter of DLIS data to either LAS, CSV or JSON formats. After the DLIS has been loaded, some basic editing or housekeeping on the data can be performed before it is saved to one of these 3 types of ASCII format files.

1.3 Software Bug Reporting

Since this software is under development, then some software bugs may exist, or un-intended crashes may occur. If a crash occurs, it is probably due to either un-expected aspects of the data or problems with the data. If these issues are reported, along with relevant information and data, then they can be fixed.

DLIS file structure is complicated and the file structure can be in many forms. This software has been tested on all known DLIS files I have, but it is possible that some types of DLIS that haven't been tested may be problematic. Modifications can be made for problematic DLIS files, upon request.

1.4 Disclaimer

The Well Log Viewer application is an un-sponsored personal project of author.

The author gives no warranty and accepts no responsibility or liability for the accuracy or the completeness of the information and materials contained in this website, or of the accuracy of the results produced by the Well Log Viewer software. Under no circumstances will the author be held responsible or liable in any way for any claims, damages, losses, expenses, costs or liabilities whatsoever (including, without limitation, any direct or indirect damages for loss of profits, business interruption or loss of information) resulting or arising directly or indirectly from your use of or inability to use information from this website or the Well Log Viewer software.

1.5 Version History

Well Log Viewer is a complete rewrite of some earlier software that had been in sporadic development since 2001.

Version 2.7       17-Apr-2021   
Version 2.4       05-Nov-2020   
Version 2.3       30-Apr-2020   
Version 2.2       21-Dec-2019.  
Version 2.1       18-Jul-2019.  
Version 2.0       26-May-2018.  First release