AVO analysis and seismic reservoir characterization in a deepwater reservoir in KG Basin: An integrated approach

Abstract

An integrated geophysical study was conducted to characterize a deep-water reservoir cluster located offshore in the Krishna-Godavari (KG) Basin, along the east coast of India. The seismic dataset underwent advanced reprocessing followed by targeted in-house conditioning to enhance data quality for Amplitude Versus Offset (AVO) analysis. Leveraging offset well information, the conditioned data was analyzed using rock physics and AVO techniques to identify classical anomalies indicative of hydrocarbon-bearing sands within a Pliocene-Miocene slope fan complex. AVO cross-plot analysis revealed deviations of gas sands from the wet sand/shale trend, although reliability diminished when anomalies aligned with background trends. Fluid substitution modelling and elastic property analysis further supported the identification of prospective hydrocarbon zones. To refine reservoir characterization, simultaneous angle-dependent seismic inversion was performed using four partial angle stacks, resulting in volumes of P-impedance, VP/VS, and density. These inverted attributes provided enhanced insights into reservoir geometry, fluid content, and lithological variations, contributing to reduced exploration risk and improved delineation of future drilling prospects.