--> Abstract: AVO Studies Over Bright Spot on an Offshore Oil and Gas Field of Eastern India, by S. N. Dalei, D. Chatterjee, and A. Dehadrai; #90933 (1998).
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Abstract: AVO Studies Over Bright Spot on an Offshore Oil and Gas Field of Eastern India

Dalei, S. N.; Chatterjee, D.; Dehadrai, A. B. - Geopic/ONGC

Amplitude Versus Offset (AVO) analysis was carried out in an eastern offshore oil and gas field of India. The objective was to validate the observed bright spot on a seismic line passing between the two drilled wells which have commercially produced oil and gas.

The prospect lies off the Andra Pradesh coast of Krishna Godavari basin, is controlled by growth faults, fault closures and combinational traps.

Input data was relative amplitude processed. Judicious processing sequence including few data dependent non-conventional approaches like: Statistically derived interval Q-compensation. Surface consistent predictive deconvolution and Surface consistent Previous HitresidualNext Hit Previous HitstaticsTop were applied to the data to enhance Signal to Noise (S/N) ratio in Common Mid Point (CMP) gather. The bright spot was more pronounced in relative amplitude processed CMP stack.

The display of qualitative AVO angle stack traces illustrates the increase in amplitude with offset over the bright spot. AVO attributes i.e., P-wave stack, S-wave stack, Poisson ratio stack, Restricted gradient stack and Potential hydrocarbon indicator, substantiate the AVO anomaly with enhanced amplitude values confirming the bright spot is due to gas charged clastic reservoir (class-3) other than only due to lithological changes.

In addition, few more AVO anomalies are also observed at different horizons indicating the presence of multiple pools. The vital clues derived from the AVO studies will certainly accelerate the exploration activities of the study area.

AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil