Hydrocarbon prospects across Narmada–Tapti rift in Deccan trap, central India: Inferences from integrated interpretation of magnetotelluric and geochemical prospecting studies

As the Mesozoic sediments contribute most of the oil and gas reserves of the world, we present an integrated interpretation approach using magnetotellurics (MT) and surface geochemical prospecting studies to demarcate hydrocarbon prospective Gondwana (Mesozoic) formations underneath the Deccan flood basalts of Late Cretaceous age across Narmada–Tapti rift (between Bhusawal and Barwah) in Central India. The MT interpretation shows deep (∼5 km) basement structure between southern and central part of the MT profile however, it gradually becomes shallower to either ends of the profile with a predominant basement depth reduction in the northern end compared to the southern end. The geophysical results suggest thick (2–3.5 km) Mesozoic sediments in the area characterized by deep basement structure. The geochemical analysis of the near surface soil samples indicate higher concentrations of light gaseous hydrocarbons constituents over the area marked with thick sub-basalt Mesozoic formations. Analyses of the geochemical data imply that these hydrocarbons are genetically related, generated from a thermogenic source and these samples fall in the oil-producing zone. The temperature–depth estimations in the region supports favorable temperature conditions (80–120 °C) for oil generation at basement depths. ► We study MT and geochemical data to demarcate prospective sub-basalt hydrocarbon formation. ► MT data show deep basement between south and central part of MT profile across Narmada-Tapti rift. ► Geophysical results suggest thick (2–3.5 km) Mesozoic sediments in the area. ► High concentration of light gaseous hydrocarbons over this thick sub-basalt Mesozoic formation. ► Analyses imply that the soil samples fall in the oil-producing zone.