Detection of hydrocarbon microseepage prospects using Landsat 8-based vegetation stress analysis in part of Assam-Arakan Fold Belt, NE India

• Published in: Arabian journal of geosciences 2021-10, Vol.14 (19), Article 1984
• Main Authors: Garain, Santosh, Mitra, Debashis, Das, Pranab
• Format: Article
• Language: English
• Subjects: Analysis; Anoxia; Anoxic sediments; Arid climates; Arid regions; Belts; Earth and Environmental Science; Earth science; Earth Sciences; Exploration; Geophysical data; Humid areas; Hydrocarbons; Landsat; Landsat satellites; Original Paper; Remote sensing; Semiarid climates; Soil; Soil analysis; Soil investigations; Soils; Stress analysis; Vegetation
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-021-08376-6

Continuous migration of hydrocarbons from subsurface reservoir to the surface in the form of microseepage creates a reducing (anoxic) environment in the overlying soil and sediment cover. Growth of vegetation becomes restricted in such a hostile environment, and consequently, a vegetation anomaly or stress is developed in the microseepage area. Thus, vegetation stress can act as an indicator of hydrocarbon microseepage. However, very few studies have used vegetation stress in hydrocarbon exploration, and that, too, are limited to geographical areas characterized by arid to semi-arid climates. The present study attempts to detect prospective microseepage areas by analyzing Landsat 8-based vegetation stress in part of Assam-Arakan Fold Belt (AAFB), north-east India, characterized by heavy precipitation. The correlation between hydrocarbon microseepages and vegetation stress is first tested in an accessible part of the study area by soil gasometry and geochemical analysis. The sub-study area investigation reveals that hydrocarbon microseepage-bearing areas are confined to the stressed vegetation areas having low to moderate NDVI values. Based on the sub-study area observation, stressed vegetation areas are delineated and a microseepage prospect map is generated for the vegetated parts of the study area. Available geological and geophysical data, in general, support the hydrocarbons potentiality of these regions. The study proves that remote sensing-based vegetation stress analysis can help in narrowing down prospective areas for hydrocarbons in vegetation areas of humid regions also. The study will help explorationists to find primary hydrocarbon prospective areas in logistically difficult and environmentally sensitive vegetated terrains, where conventional hydrocarbon exploration is extremely challenging and, thereby, will save exploration cost and time.