Ground Water Prospect in the Adjoining Areas of the Belt of Schuppen: Kharsang Oilfield Area of Arunachal Pradesh, North-East India

The Kharsang Oilfield, operated by GeoEnpro Petroleum Limited, is located at Kharsang and Jairampur Circles of Changlang district in Arunachal Pradesh. Geologically the Kharsang oil field is a roll over anticline associated with the Margherita Thrust System of the Belt of Schuppen where the older Tertiary sediments in the Kharsang area are lying over the younger Tertiaries owing to the effect of the Margherita thrust. Thus the Barails occur immediately below the 10 to 50 m thick alluviums while the younger Namsangs occur in the deeper horizons below the Margherita Thrust zone. At present, the total water requirement (about 100 klpd) of the oilfield is entirely drawn from the Namphuk river flowing across the area. In order to create an alternate source based on ground water, a hydrogeological study was carried out in an area of 32 km² covering Kharsang Oilfield and its adjoining areas for finding out the feasibility of construction of moderately deep tube wells with suitable discharge. For this purpose hydrometeorology, soil characteristics, topographic relief & slope, thickness & extension of subsurface aquifer zones and various hydrogeologic characteristics have been studied for the assessment of ground water prospect of the area. Three potentially favourable zones have been identified which have the potential for providing a sustained supply of water but only at a relatively lower yield.