LIS 79 to LAS 2.0
LIS (Log Information Standard, 1979) is the format older wells were delivered in, typically logs from the 1980s and 1990s copied from tape to CD or into a national data repository. Very few current programs read it, so the curves often sit unused next to a scanned print.
Upload one or more .lis files, or a .zip of the well folder, and each data format
specification in every logical file becomes a LAS 2.0 file with:
- the depth range, step and direction as recorded (logging up gives a negative step);
- the well section filled from the CONS and wellsite tables of the file: company, well, field, state or county, date and the other values the logging engineer entered;
- every curve with its LIS units, and the remaining table entries (mud properties, temperatures, tool settings) in the parameter section.
Choose "LAS 2.0 files only" to skip the CSV, Excel and PDF, or keep "Everything" to also get a log print and an Excel workbook.
Fast channels
LIS lets a curve be recorded several times per depth step; micro-resistivity and some nuclear curves often are. Those curves cannot share rows with the others, so they get their own LAS file named "3x sampled channels" (or whatever the rate is), with a depth for every sample. The frame depth belongs to the last sample of each step and the earlier samples are spaced evenly before it, as the LIS 79 rules describe.
Tape images
Logs copied from tape are often stored as tape images, with a small marker before every tape
block. These files are recognised and read the same way. If yours carries the .tif extension,
put it in a ZIP (or rename it to .lis) before uploading, so it isn't taken for a picture.
Pitfalls
- Depths in LIS are usually stored in tenths of an inch; they are converted to feet, or to metres if you choose.
- Dipmeter files hold raw pad data in vendor-specific blocks. Those channels are listed in a note and left out; the deviation, azimuth and caliper curves are converted.
- A tape copy that stops part-way is read as far as it goes, with a note.
More about what this tool reads and writes: Well Log Converter (DLIS, LIS, LAS).