Two-term inversion from AVO to detect combined effect of porosity and gas in a cretaceous sand reservoir
This case study demonstrates predictions of lithology and porosity variations for a high acoustic impedance gas sand. The approach combines three techniques to estimate and interpret an acoustic impedance and Poisson ratio term by: (1) generating with AVO analysis a Normal incidence (NI) and Poisson Reflectivity (PR) from RC ({theta}) {congruent} NI cos{sup 2}({theta}) + PR sin{sup 2}({theta}); (2) applying a recursive inversion method to independently generate estimates of acoustic impedance (pV) from NI and Poisson ratio ({sigma}) from PR; and (3) utilizing a crossplot method to simultaneously display pV and {sigma} as a color-coded section portraying variations in lithology, porosity and pore fluid. This approach overcomes limitations in stack seismic inversion to discriminate porosity from lithology. It also extends application of AVO to sands with pV exceeding shale pV.
- OSTI ID:
- 542827
- Report Number(s):
- CONF-951013--
- Country of Publication:
- United States
- Language:
- English
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