Sunil K. Srivastava¹, Sampad K. Jena¹, Manash Chatterjee¹
(1) Oil India Limited, Assam, India

Abstract: Lower Eocene Lakadong oil and gas fields - A fast emerging deeper play in a matured petroleum province in parts of Upper Assam Basin, India

Oil and gas fields of Lakadong member of Sylhet formation of Lower Eocene has emerged as an important new play during last one decade in the parts of Upper Assam Basin, India with strong regional potential. The reservoir units comprising of fine to medium grained sandstones with interbedded shale/carbonaceous shale and coal have been deposited in a shallow marine tidal flat and barrier bar environment. The reservoir sands commonly exist in the depth range of 3500-4700m, are generally very thin (1-3m) and display rapid lateral variations. This reservoir/play has porosity ranging from 10 to 25%, permeability in the range of 50 to 4000 md and generally having a reservoir pressure of 600 psi above hydrostatic with a strong edge-aquifer drive support. The play is typified by wells capable of producing 1000-1500 bbls of oil per day. The Eocene play includes 21 medium to small size new fields with in-place reserves of 400 million bbls. Initial discovery was made in 1990 at a Lower Eocene Test in Dikom Field located close to Pre-Cambrian Basement High. The largest pool discovered to-date is Kathaloni field, which has 24 producers and estimated total reserves of 40 million bbls.

This deeper play has been discovered in a matured petroleum province where Naharkatiya and Moran oil fields of Oligocene age are producing since early 1950’s. This paper discusses geologic, well-log, seismic and production data for this play which promises to expand considerably in the years to come.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana