A Look into a New Feature: Pre-Stack Coloured Inversion

Ever thought about Kingdom Pre-Stack Coloured Inversion? Usually, Coloured Seismic Inversion is a post-stack method but we have recently extended our CI into the pre-stack domain. This offers a higher grade of detail with multiple attributes being generated quickly.

What is Pre-Stack Coloured Inversion?

We start with Pre-Stack Angle Stacks and do AVO Analysis to produce Intercept A and Gradient B and then Coloured Inversion of the A and B stacks is run to generate relative intercept impedance (II) and gradient impedance (GI). These then need to be rotated in to the EEI inversion (Extended Elastic Impedance) domain to produce the optimal chi for either an elastic or petrophysical parameter.

Once A stack and B stack volumes have been created in Pre-Stack Inversion module, they are utilised in the Pre-Stack CI module. Previously in CI it was only A stack (Acoustic Impedance) that could be utilised but now in Pre-Stack CI, the B stack (Gradient Impedance) can also be used. The user now has a choice between choosing to invert Acoustic Impedance (AI), Shear Impedance, Density or Elastic Impedance. Elastic Impedance is a very general term which depends on the Chi angle – if Chi is 0° EEI is zero and it will be equivalent to AI. If the Chi angle is 90° EEI is equivalent to gradient impedance!

With your A stack and B stack volumes ready the user will use the new EEI Correlation tab in Pre-Stack CI to find the optimum Chi for each rock property.

Next Steps

Choose a log and the correlation coefficient will be calculated. The highest correlation will give the best match between the EEI curve and the target log.

Using the new EEI Impedance tab in Pre-Stack CI, simply select the volumes generated and the related log and put in the Chi angle generated in the EEI correlation tab for the rock property you want, and the volume will rotate by that Chi angle to give you firstly the display of that volume and secondly the output of the volume.

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