Identification and analysis of bottom simulating reflectors in the Foz do Amazonas Basin, Northern Brazil

Abstract

This work proposed an additional approach to investigate gas hydrate occurrences in the Foz do Amazonas Basin, in the Brazilian Equatorial Margin. The automatic comparison of seafloor seismic amplitudes with those from the Bottom Simulating Reflectors (BSR) was used to exhibit the reversal of signal polarities among the seafloor (positive) and the BSR (negative), reinforcing the identification of BSR in areas where its visualization was unclear. Additionally, we used the envelope attribute to highlight the BSR in the seismic section. Subsequently, we decomposed the seismic data into different frequency bands, applied a -90 degrees phase rotation to the data and recalculated the envelope attribute for each section decomposed in frequency bands. This technique improved visualization, allowing the identification of intervals where BSR were laterally discontinuous, revealing to be valuable for mapping the gas hydrate distribution in Foz do Amazonas Basin.

Analysis of seismic attributes to enhance a Bottom Simulating Reflector (BSR) in the gas hydrate area of Umitaka Spur, eastern margin of Japan Sea

“…Seismic attributes are the main tools used to predict lithology of seismic reflection data, which can act as filters that quantify properties of seismic images (Taner, 2001). There are several studies that apply seismic attributes in order to investigate the presence of gas hydrate in different regions of the world (e.g., Hato et al, 2006;Santos et al, 2009;Oliveira and Oliveira, 2009;Joshi et al, 2017;Aguiar et al, 2019Aguiar et al, , 2021. Thus, this work aims to evaluate the best seismic attributes for identification of BSR in a widely studied gas hydrate site, Umitaka Spur, Joetsu Basin, Japan (Fig.…”