Hydrocarbons in Sub-basalt Sediments - Basin Modeling of Kerala-Konkan Basin, Offshore West India

Mesozoic sediments in the western flank of India are covered by flood basalts that were prevalent at the Tertiary-Cretaceous boundary. In this paper, we present combined results of seismic interpretation and a study of basin simulation and modeling of Kerala-Konkan offshore deep-water west India. The model has been simulated in different scenarios, which account for the variation of the reservoir and of the source rock lithology. This was done for the purpose of understanding the nature of possible sub-basalt hydrocarbon leads and prospects. The Kerala-Konkan Basin has neither undergone extensive structural deformation nor has been greatly influenced by the post-basalt river sediment deposition systems. Thus, it represents the ideal basin to study the thermal effect of flood-basalts on the pre-existing Mesozoic sediments. Hydrocarbon reserves, if in existence, are herein trapped either against the basement highs or pinch-out stratigraphically against basalt. The hydrocarbons are considered mostly to be in the gas window as it seems that the geothermal gradients are derived from high basal heat flow due to rifting and volcanic eruptions these may have resulted into the secondary cracking of the oil into gas.