Subdivision of Carbonate Platform Developmental Stages Based on Seismic Attribute Analysis: An Example from the Indus Fan Offshore Basin

Carbonate formations host abundant hydrocarbon resources and constitute a key target for current and future petroleum explorations. A massive Paleocene-Eocene carbonate platform system overlies Late Cretaceous Deccan volcanic rocks within the Indus Fan Offshore Basin. Low geophysical exploration maturity and insufficient targeted research on carbonate reef identification and platform evolution hinder hydrocarbon discoveries in this region. Using 2D seismic data, this study employs multiple seismic attribute methods to characterize carbonate reef-related anomalies. An innovative reef identification method based on a weighted superposition of spectrally decomposed amplitude spectra is proposed to delineate reef-prone sedimentary facies and characterize the multi-stage evolutionary patterns of the carbonate platforms. Based on quantitative constraints from seismic reflection and amplitude differences, platform evolution is classified into four clear phases: initial development, platform expansion, gradual decline and platform drowning. The initial development phase shows prominent high-amplitude and low-frequency seismic responses, and intervals with such high-amplitude responses may indicate favorable reservoir potential. Platform margin zones show the most prominent amplitude anomalies and are considered priority exploration targets, suggesting excellent hydrocarbon potential within strata formed during the initial platform stage. This study provides quantitative geophysical support for the stage classification of Paleocene–Eocene carbonate platforms in the Indus Fan Offshore Basin, and offers practical guidance for carbonate reservoir exploration and the prospect evaluation of analogous basins worldwide.