Abstract

Sequential restoration of seismo-geological model is a common practice in fold and thrust belt to know the kinematics of thrusting and evolution of structures through time. Restoration of two such regional profiles in Kangra-Mandi area of Himachal Pradesh covering from Main Boundary Thrust (MBT) to Himalayan Frontal Thrust (HFT) illustrates around 29% and 35% shortening respectively. A few structures came into existence near Balh, Changartalai, Hamirpur and towards hinterland area during sequential restoration. Occurrences of hydrocarbon shows in these structures during drilling also indicate importance of these structures as hydrocarbon locales. Moreover the study reveals that some of the thrusting events and its related structurization are likely to have come into existence during or before the expulsion of hydrocarbons and stand a good possibility in entrapment mechanism. Gentle structure in the sub-thrust of Drang Thrust, Palampur Thrust and Splay of MBT may hold primary reservoirs within Subathu Formation. The study also suggests that an up-gradation of the well top of Upper Dharamsala is required in well JMI-G as around 2933m thick Lower Siwalik was drilled at the up thrust of Jawalamukhi Thrust, which appear anomalous when compared with the nearby drilled wells in this area. A proper structural modeling is also useful to identify the nature of thrusts i.e. whether it is deep seated or shallow, amount of shortening and related up-liftments, volume of erosion of different rock types etc. Moreover structural model helps in validation of sub-surface buried faults, which can control surface morphotectonic features.