This small utility was developed to quickly generate AVO curves based on a simple isotropic interface model from a LAS file containing p-wave, s-wave and density logs.

It utilizes the exact solution of Zoeppritz equation for incident angle dependent Rpp (Aki and Richards, 1980), and the linear Shuey equation for intercept and gradient calculation.

Stochastic realizations of a selected interface can be computed by Monte Carlo simulation based on random sampling of correlated multi-gaussian distributions using Cholesky decomposition.

2D probability density functions of Rpp or P-G can be generated using the simulated realizations.

The generated realizations and interface models can be exported for further analysis. Generated 2D PDF can be exported in Rokdoc format.

 The workflow is simple:

  1. Load your LAS file,
  2. Define the Vp, Vs and Density logs
  3. Change the units of velocities if necessary
  4. Define your layers
  5. Store your interface model in the model list
  6. Run probabilistic analysis from a stored interface by double click on the interface name
  7. Generate 2D PDF from realizations
  8. Export 2D PDF



Model definition: ctrl+left click

Zoom on logs: left click +drag

Unzoom: left click

Pan: right click+drag

Interfaces can be saved or delete with +/- buttons


FileDescriptionFile sizeLast modified
Download this file (logAVO.exe)logAVOwin32/win64 executable3676 kB2015-05-25 10:07
Download this file (logAVO.zip)logAVO zipped versionzipped to solve download problems1393 kB2015-05-06 17:04



Aki, K, and PG Richards (1980). Quantitative Seismology: Theory and Methods. WH Freeman and Co.

Shuey, R.T.  1985.  A Simplification of the Zoeppritz Equations  -  Geophysics, 50, 609 - 614


The application was coded using FPC and Lazarus. Dmath library was used to code the hard stuff. Images from FatCow Farm Fresh Icons were modified to use in this app.

logAVO Rpp


prob setup

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logAVO 2DPDF pg gas