Performance of Digboi Refinery Modernization Project From Geotechnical Aspects — Investigation and Observations

Digboi Refinery is the world’s oldest refinery in simple form which is producing oil since 1889 till present with its modernized setup. Its first well was dug manually during 1889 and crude oil was found at 54m depth only. This phenomenon has encouraged establishing an industry on oil producing business, and accordingly a form of first refinery was comeout in 1889. 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, which is in fact commissioning during 2007 onward as a completely modernizied refinery. Geotechnical investigations for this modernization project was started during 1987 and completed during 1992. As a whole the investigation works were completed under time bound work of three different phases of investigations with various engineering requirements. Besides laboratory investigations, field investigation includes mainly boreholes with SPT, DCPT, SCPT, VST, CBRT and Block vibrations tests. After careful studies, based on the field and laboratory investigations various types of shallow and deep foundations were suggested. Design and constructions were made based on the suggestion provided more particularly to overcome the problems pertaining to the high seismicity of the area and potential to dynamic liquefaction point of view and executed the same at site accordingly. Observations were made till date are found highly satisfactorial to engineering aspects.