Abstract

The Upper Assam Basin is a well known petroliferous sedimentary basin of India. Exploration for hydrocarbon started way back in 1866 and commercial oil was first discovered in 1889 in Digboi. Thereafter exploration continued and a number of oil and gas fields have been discovered in Oligocene and Miocene formations. In the year 1991 a very remarkable event in the history of petroleum finding in the basin took place, the discovery of Eocene /Palaeocene reservoir in the Basement High area which shifted the focus of petroleum exploration from Oligocene /Miocene dominancy. Thereafter, at least 10 Eocene/Palaeocene fields have been discovered within a span of 15 years with commercial production. Generally, the reservoirs in Palaeocene /Eocene formation are thin and discontinuous in nature but with good reservoir characteristics. Sand to sand correlation in Eocene reservoir are very much inconsistent but as a group they seems to be consistent and traceable in large part of the area. An attempt has been made to identify different genetical groups in a centrally located oil/gas field have identical depositional environment, lateral distribution and possible extension etc.