GUIDE
Convert a scanned well log to LAS
In short
- A scanned log is a picture. To get a LAS file you calibrate the picture to depth and curve scales, then trace the curves.
- Log Digitize does this in the browser and exports LAS, CSV or Excel at the depth interval you choose.
- Untraced depths are written as null (−999.25), so nothing is invented where you did not trace.
What you need
A scan or PDF of the log with a readable depth scale and printed curve scales (the left and right values of each track). Calibration needs two known depths and, for each curve, its left and right values.
Steps
- Open the scan. Open the PDF or image in the workspace, or try the sample log first.
- Calibrate depth. Enter two known depths and pick their marks on the scan. Choose feet or metres.
- Calibrate each curve. Enter the track's left and right values, pick the track edges and choose a linear or logarithmic scale (resistivity is usually logarithmic).
- Trace. Click anchors or draw a smooth stroke with the pen, or right-click the printed curve for automatic tracing. Undo restores the previous trace.
- Check. Run the data checks for values outside the printed scale, spikes and gaps.
- Export. Tick the curves, choose the sampling interval and export LAS, CSV or Excel. You can also add well information such as company, field, API number and elevations so it is written to the LAS header.
What the LAS file contains
Depth plus one column per traced curve, sampled at your chosen interval by interpolating between traced points. Missing values are −999.25. The header carries the well information you entered. LAS 2.0 and LAS 3.0 are both available; see the LAS 3.0 and 2.0 guide.
Tips for accuracy
- Use a high-resolution scan; faded ink and grid lines are the main source of tracing errors.
- Calibrate against depth marks far apart on the log.
- Check wrapped curves: use a backup scale where a curve wraps around the track.
- Always compare the traced curve with the scan before relying on the data.
Common questions
Can I trace upward as well as downward?
Yes. You can resume in either direction.
Is my scan uploaded?
Your logs and digitized data stay on your computer.
Related guides
- How to digitize a scanned well log and export LAS
- Digitize a PDF well log
- Calibrate a log curve scale
- All guides
Try the sample log in your browser · Back to the introduction