The response of a given seismic anomaly is examined over a range of Extended Elastic Impedance projection angles to determine how robust the feature is. This is compared to the EEI response of offset wells.

Seismic inversion results are interpreted in the light of rock physics results at offset wells. For example, the anomaly is typically assessed to see whether it varies in a manner consistent with a range of EEI logs, rather than simply matching a single “fluid enhancement” log.

INVERSION AND INTERPRETATION

Extended Elastic Impedance

Inversion interpretation involves the use of multiple attributes from either Extended Elastic Impedance (EEI) inversion or Pre-Stack / Simultaneous inversion (or both) rather than a single “fluid” and “lithology” attribute. It can also entail the generation of mathematical combinations of these attributes. The other key inputs are an understanding of the rock physics at offset wells, the geological setting, and the geometry of the anomaly (depth conformance etc). From these components we assess the likelihood of a given seismic anomaly being caused by hydrocarbons.

Example Extended Elastic Impedance logs.

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