Free Online Well Log Correlation Panel: Multi-Well Cross Sections

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Load the demo wells or your own LAS files. The gamma ray curve from each well plots side by side.
Formation tops (well number, top name, depth; one per line)
Each column is one well showing its gamma ray curve (low GR sands shade yellow). Tops you enter are drawn as colored lines and connected between wells. Choose a top in the flatten selector to hang the section on it stratigraphically, the standard trick for seeing thickness changes instead of structure.

Correlate wells in your browser

The tool above draws the panel every subsurface geologist builds first: gamma ray logs from multiple wells side by side, formation tops marked and connected between columns, and the whole section optionally flattened on any top you choose. Load up to four LAS files, or press the demo button for three synthetic wells whose sands visibly thin from left to right. Type your tops as simple well, name, depth lines, and the correlation lines draw themselves. When the panel says what you want it to say, download it as an image for a report or slide.

Three well log columns side by side with gamma ray curves, two formation tops drawn across all wells and connected by correlation lines, illustrating thickness changes between wells
Three wells, two tops, one story: the correlation panel makes thickness changes and pinch-outs visible at a glance.

This completes the eight-tool Geoscience Workbench, linked in the bar above: from SEG-Y sections through single-well logs to the multi-well view that turns wells into geology. As always, your LAS files never leave the browser.

Why flattening matters

Drawn at true depth, a correlation panel mixes two signals: structure (the wells sit at different elevations on a dipping or faulted surface) and stratigraphy (the rock packages genuinely change thickness). Flattening hangs every well from the same top, subtracting the structure so only the stratigraphic signal remains. A sand that looks continuous at true depth may reveal itself as thinning onto a high once flattened, and that thinning direction is often the single most valuable exploration observation a three-well panel can make. Toggle the flatten selector back and forth and you are doing exactly what workstation software does with the same button.

Reading a panel like an interpreter

  • Low gamma ray intervals shade yellow: those are your sands, and the first question is always whether the yellow zones connect between wells or pinch out.
  • Divergence between two correlation lines means the interval between the tops is growing, the signature of syn-depositional accommodation.
  • A top that must cross another to correlate is a warning: either a pick is wrong or a fault sits between the wells.
  • Keep tops honest: a correlation panel is a hypothesis, and the discipline of typing each pick as a number is half its value.

What this tool is for

Quick correlation of a handful of wells, teaching the flattening concept interactively, and producing clean panel figures without a workstation license. It plots the gamma ray curve, which drives most clastic correlation; multi-curve tracks, fault gaps, and dozens of wells belong to full correlation packages. For the three-to-four well question that starts most subsurface arguments, this settles it in the browser.

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