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Tools/Log Viewer
WELL DATA × DEPTH

Online LAS log viewer.

Plot your logs, calculate in Python, and keep code, results and tracks together.

RELEASE 24
Hosted libraries ↗Python librariesLAS formatsHow to use this toolWorked examplesAgent guideCopy an AI prompt ↗

Python works without a LAS. Load a LAS to plot well logs or save a well project.

Well logs

Waiting for your LAS file

4 TRACKS · 0 CURVES
— m

Your well, in depth.

Choose a LAS file, then drag its curves into the tracks.

DEPTH · m—
Hover or tap to read values · Drag to pan4 empty tracks
Depth increases downward.Missing data stays blank. Curves are clipped at scale limits.
LAS LOG VIEWER · VERSION 20Explore relationships in the crossplot →

Open a LAS file and plot well logs online

Load a well-log LAS file through version 3.0 and place any of its curves on four depth tracks. Use GR, resistivity, density, neutron or sonic logs together, with independent scales and line styles. File contents are processed in your browser.

Build your display

Drag a curve onto a track, or select it and use the track’s + button. Open Track setup to set left and right limits, reverse a scale or choose a logarithmic display.

Calculate shale volume

Open Vsh from GR, choose the source and enter clean-rock and shale references. Add the resulting 0–1 VSH_GR curve to any track.

Calculate porosity and Sw

Set matrix and fluid density endpoints to compute PHID. Use that porosity or a LAS porosity curve with Rt, Rw and your Archie parameters to compute SW_ARCHIE.

Add meaningful fills

Fill to a baseline such as GR 75 gAPI, or between two curves. Left and right colours follow displayed positions, including reversed and unequal scales.

Save and reproduce

Export the visible plot as a PNG with legends. Save JSON settings and reload them alongside the same LAS to restore tracks, depths and fills.

How to open and plot a LAS file · Complete Log Viewer reference · Gas, oil and water example

CURVES, DISPLAY & FILLS

Track setup

Set each curve independently. Min is the left edge; max is the right edge. Min > max reverses the scale.

Changes apply to this track only.
SHALE VOLUME · LINEAR GR

Vsh from GR

Choose your GR curve and enter the clean-rock and shale reference values in its recorded units.

Vsh = (GR − GR min) / (GR max − GR min)

Output is limited to 0–1 v/v. GR min must be smaller than GR max. Missing samples stay blank.

Result: VSH_GR in the curve list. Drag it into any track, or use the track’s + button. Recalculating updates the same result curve across all tracks.

Calculated across the full LAS.
DENSITY POROSITY · USER ENDPOINTS

Porosity from density

Choose bulk density and provide the matrix (zero-porosity) and pore-fluid (100%-porosity) endpoints.

φD = (ρma − ρb) / (ρma − ρfl)

Enter both endpoints in g/cm³. A kg/m³ input curve is converted for this calculation only. Matrix density must exceed fluid density; both must be positive.

Unchecked: keep negative and above-one results for QC. Missing or non-positive density stays blank. This is an apparent density porosity; no shale or gas correction is applied.

Result: PHID · v/v. Add it to any track. Updating it also recalculates Archie Sw if that result uses this porosity.

Calculated across the full LAS.
WATER SATURATION · ARCHIE

Archie water saturation

Use your porosity and resistivity curves with formation-water resistivity and Archie parameters.

Supply Rw already corrected to formation temperature. Select a suitable Rt curve, usually deep resistivity. No temperature or invasion correction is applied here.

Sw = [a × Rw / (Rt × φm)]1/n

φ is a fraction in the equation. The starting values a = 1, m = 2 and n = 2 are editable: use your calibrated parameters. Archie assumes an appropriate clean, non-conductive matrix model.

Unchecked: retain values above one for QC. Missing inputs, φ ≤ 0, φ > 1 or Rt ≤ 0 stay blank.

Result: SW_ARCHIE · v/v in the curve list. Porosity may come from your LAS or the density calculation.

Calculated across the full LAS.