Schlumberger Resistivity Soundings Modelling and Inversion

Developer/PublisherG. R. J. Cooper
Operating SystemsWindows
License optionsStandard, Educational



VES for Windows allows the forward modelling and inversion of data from Schlumberger resistivity soundings.

Figure 1 - Example Display

The upper portion of the display shows the observed field data and the calculated response of the model. The least-squares error in the fit is displayed at the upper left. The dashed line plots the resistivity and the thickness of the model.

The lower portion of the display represents the model itself. The resistivity and thickness of each layer is shown on the left, and the Dar Zarrouk S and T parameters are shown on the right.

Changing the Model

The parameters of any layer may be changed by clicking upon it with the mouse. The following dialog will the appear:

Figure 2 - Change the Layer Properties

The resistivity and thickness of the layer selected are displayed. New values can be entered, then the OK button pressed, and the model will be updated. Alternatively, pressing the spinbutton adjacent to the resistivity or depth will change its value by that amount and update the model. The increment/decrement value may be changed as necessary.

If it is desired to invert the resisivity or thickness value, then the checkboxes displayed can be clicked upon. The limits for the inversion can be entered also.

Layers may also be added or deleted. There may be up to 10 layers in the model.

Inversion Options

Inversion is a mathematical technique wherein the model is modified automatically to improve the fit between the field data and the model response. In this case, the thichness' and resistivities of the layers are the parameters that may be inverted. Up to 10 parameters may be inverted in total. Once the parameters for inversion have been selected (as described above), the inversion itself may commence. Choosing the inversion option calls up the following dialog box:

Figure 3 - Invert the Model

As the inversion proceeds the model will be updated automatically onscreen.

Display Options

The portion of the screen containing the data curves may be varied from 30% to 100% of the display.

Automatic Interpretation of Two and Three layer Models

An initial model will be determined from the inflection points of the data curve, and this will then be inverted. This procedure works best with relatively noise-free data.

Figure 4

Help Options

A full Microsoft Windows hypertext help system containing the whole program manual has been implemented.

Program Specifications

Up to 50 field data points may be used.
Up to 10 layers may be present in the model
Up to 10 parameters (Eg a thickness or resistivity) may be inverted.
Output of the model to
Hardcopy to any Windows supported device.

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System Requirements:



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This software is now FREEWARE "as is". It may be downloaded for free use.
As this software is now FREEWARE GeoMEM cannot provide any form of support or technical help. You are advised to contact G.R.J. Cooper direct for any help you need or any comments you have about the software.

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