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Digboi Refinery-Our Second Century


A century ago just before the World War I, history of another kind was in the making in a remote corner of Assam in the midst of the dense and malaria infested jungles by a band of intrepid pioneers searching for black gold. Italian Engineers, commissioned by the Assam Railways and Trading Company, which has already established Tea Gardens, Coal Mines and Timber Mills in the remote North-Eastern part of Assam, to build a railway line from Dibrugarh to Margherita (headquarters A R T & Co.) accidently discovered oil at Digboi. It was here in Digboi that the first commercially viable well in India, known locally as well No.1, was successfully drilled in September'1889 and first modern refinery in India was built and commissioned in December'1901 to supplant a small "batch-still" refinery in Margherita.

Digboi Refinery at the initial stages

When oil was discovered in remote Digboi there was no habitation in its immediate neighborhood. The jungle was dark and swampy. The forest was so thick and the undergrowth so dense that sunlight could never reach the ground. Once oil was found, the dense jungle made way for the growth of the oil industry in India.

Over the past 100 years, Assam Oil and the petroleum industry of India with Digboi as its nucleus has been very much a part of this existing period. While looking back on the past with respect and to the future with confidence, we portray here how Digboi Refinery was successful in meeting the needs and challenges of the times, and how Digboi Refinery played a role in shaping and developing history over the past 100 years.


Digboi is now Headquarter of Assam Oil Division of Indian Oil Corporation Limited. The Earliest recorded to the existence of oil in India is found in the memories and despatches of the Army Officers who penetrated the jungles of Upper Assam since 1825. Lt. R. Wilcox, Major A. White, Capt. Francis Jenkins, Capt. P.S. Hanney -- they all saw at different times' petroleum exuding from banks of the river Dehing. Mr. C.A. Bruce(1828) and Mr. H.B.Medicott (1865) of the Geological Survey of India also saw oil while perspecting for coal in Upper Assam.

First Commercial Viable well in India locally known as Well No.1

Mr. Goodenough of McKillop, Stewart & Co. Calcutta was the first in India to start a systematic programme of drilling for oil in November'1886, at Nahorpung about 30 miles south east of Dibgoi, just seven years after the World's first commecial oil well was drilled in 1859, by Col Willam Drake in Pennsylvania, USA. This hand dug well-first oil well in India was drilled upto 102 feet and proved dry. However the second well, struck oil at Makum near Margherita, about 8 miles from Digboi.

"betch-still" use in Margherita Refinery Unit

The Assam Railways & Trading Company while extending the Dibrugarh-Sadiya Railway line upto their coal fields in 1882 came across oil seepage near work sites around present Digboi. Although drilling for oil first began in 1886, by Assam Railways and Trading Company, it was not until 1889 that the first commercially viable well was struck at Digboi. India's petroleum industry thus started taking shape with the commercially successful discovery of oil in Digboi. The Assam Oil Company(AOC was formed in 1889 to take over the oil interest of the Assam Railways & Trading Company and the Assam Oil Syndicate, who had carried out the early drilling in the area.

The Digboi Refinery was commissioned in December'1901 and supplanted the earlier small refinery unit at Margherita. The Digboi refinery, commissioned in December'1901 is today India's oldest operating refinery. Over the 100 years it has undergone a transition from being an age old refinery to one with state-of-the-art technology comparable to any modern refinery.

Digboi Refinery at Present

The Digboi Refinery modernization project was taken up in large scale in order to overcome the technological obsolescence of the old refinery. Subsequently a number of other major projects were undertaken by Assam Oil Division to further revamp and modernise Digboi Refinery. This includes the Wax Hydro-finishing Unit(WHU) which is now under commissioning, the Solvent Dewaxing/ Deoiling Unit(SDU) where the target date of commissioning is November'2002. The Target date of commissioning of Hydrotreater is May'2002 and the target date of commissioning of the Vacuum Residue Short Path Distillation(VRSD) is October'2002. Digboi refinery has been awarded the ISO-14001 and OHSMC certificate.


With development in technology and infrastructure, Assam Oil Division is moving towards attaining higher standards of excellence. With a name that has existed for over 100 years, ready to meet the challanges of the future with its greatest resource - a committed and talented workforce. Assam Oil Division has always upheld its commitment towards the community at large, as a good corporate citizen. It has been carrying out various developmental activities in the region. In its journey forward it belives in carrying along with it, the community with which it co-exists.
Today with its modern technology and facilities, Digboi Refinery produces major petroleum products like fuels, wax, bitumen and range of specialty products. This hundred year old Digboi refinery can very well be said a technical marvel of the past and present.