GRSG 35th Conference 2024 Abstract

Title: Characterization of micro seepage-induced diagenetic changes in the Upper-Red Formation, Qom region, Iran. Part III: Using Hyperspectral EnMAP Satellite Data

Author: Yasmin Elhaei

Organisation: Shahid Chamran University of Ahvaz- Iran

This study leverages the advanced capabilities of EnMAP hyperspectral data to map alteration mineralogy induced by active hydrocarbon microseepage systems within the strata of the Upper-Red Formation (URF) in Qom area, Iran . Previous studies have shown that the URF strata overlaying the Alborz petroleum reservoir, have undergone significant mineralogical changes due to long term leakage of hydrocarbons to the surface and near-surface environment. The Level 2A data product from EnMAP was processed using spectral matching and polynomial fitting techniques to detect the mineralogy and the characterize the key absorption features of alteration minerals.

A distinct suite of mineralogical indicators associated with microseepage systems was identified and mapped over the study area. These include partial bleaching of red bed facies, widespread formation of secondary goethite coatings along the anticline axis, development of ferrous iron minerals indicative of secondary chlorite in affected zones, and extensive distribution of calcite and clays (montmorillonite) over the Alborz oil reservoir.

The results were validated through laboratory spectroscopy of the samples collected from both affected and unaffected zones, along with optical microscopy and whole rock geochemistry. Compared to multispectral remote sensing data from the ASTER and Sentinel-2 instruments, EnMAP demonstrated superior accuracy in delineating the boundaries of affected zones and more effectively identifying and characterizing individual minerals, thereby complementing field observations. This study highlights the advantages of EnMAP hyperspectral data in mapping digenetic mineralogical changes in sedimentary environments, facilitating remote sensing microseepage detection, and advancing petroleum exploration in arid to semi-arid regions.