A look at Pre-Stack Colored Inversion

Have you thought that it would be possible to perform a Pre-Stack Coloured Inversion? Usually,  Colored Inversion (CI) is a post-stack method but we have recently extended our CI into the pre-stack domain as part of the upcoming release of Kingdom Seismic Inversion. This improves the detail of the volume and quickly generates multiple attributes.

So what is Pre-Stack Colored Inversion?

The procedure begins with Pre-stack Angle Stacks. You can then perform AVO Analysis to produce the Intercept A and Gradient B  stacks. Then Colored Inversion of the A and B stacks can be run to generate relative intercept impedance (II) and Relative gradient Impedance (GI). These are then rotated to Extended Elastic Impedance using an optimal chi angle to generate each elastic or petrophysical parameter.

After the A stack and B stack volumes have been generated in the Pre-Stack Inversion module, they can be subsequently utilised in the new Pre-Stack CI module. In previous versions of the software, in CI it was only A stack (Acoustic Impedance) that could be used, but now in Pre-stack CI the B stack (Gradient Impedance) can also be used. You now have a choice between choosing to invert Acoustic Impedance (AI), Shear Impedance, Density or Elastic Impedance, the latter being a very general term which depends on the Chi angle. If Chi is 0° EEI is equivalent to AI. If the Chi angle is 90° EEI is equivalent to gradient impedance! Through selection of your petrophysical logs, the software can automatically ascertain the chi angle for any elastic parameter you could wish for!

With your A stack and B stack volumes ready you can use the new EEI Correlation tab in Pre-Stack CI, where you can see the high, or low, point on the graph indicates the highest correlation (either positive or negative) which indicates the optimal Chi value you can select to create your desired EEI volume.

Next Steps

You can then use the new EEI Impedance tab in Pre-Stack CI and simply select the volumes generated and the related log. Then put in the Chi angle generated in the EEI correlation tab for the rock property you want. This will rotate the volumes by that Chi angle to firstly give you the display of that volume and secondly output the volume. This new tool allows reservoir properties to be mapped such as porosity, oil/gas saturation and shale volume.

In minutes you will have high quality volumes for display in Kingdom.

If you’d like to know more about Kingdom Seismic Inversion then click here. To contact us for a free evaluation e-mail us on sales@equipoisesoftware.com.

The software is provided by S&P Global (who we partner with for Kingdom) with perpetual and subscription pricing available on request. We offer a series of Teams meetings throughout the evaluation to help you quickly step up the learning curve and enable you to see the results for yourself.