Executive Summary

EXECUTIVE SUMMARY INTRODUCTION The Khagarijan Field of Oil India Limited (OIL) is a part of the Tinsukia PEL area located in Dibrugarh and Tinsukia districts of Assam. OIL had submitted Form-1 of the EIA Notification, along with a Draft Terms of Reference (ToR) for EIA study to MoEF. MoEF has issued approved ToR vide letter No. J-11011/105/2012-IA II (I) dated 18th July 2012. SENES India has been entrusted by OIL to undertake an Environmental Impact Assessment (EIA) study for Khagarijan Field located at the Dibrugarh and Tinsukia districts in Assam. The EIA study comprised of initial scoping & site visit, environmental monitoring & surveys, preparation of draft EIA-EMP report for Public Hearing (PH). Block Location & Accessibility The Khagarijan Field of OIL covers approximately 675 sq. km area and is located in Dibrugarh and Tinsukia districts of Assam. The geographic location of the Khagarijan Field is included within the Survey of India’s Topo- Sheet No. 83M2, 83M3, 83M6 and 83M7. The Field is located to the south of the Brahmaputra River. NH 37(AT road) is the most prominent road in the region. The road runs through the southern side of Khagarijan Field, in an east to west orientation. This road connect Tinsukia town located in the south eastern corner of the Field, with Dibrugarh town located on the south western side, outside the Field. The northern side of the block is not easily accessible due to the stretch of Brahmaputra River on the west and Dibru-Saikhowa National park in the east. Tinsukia Junction and New Tinsukia Junction are the major railway stations within the Field and are located at the Guwahati-Dibrugarh line of North East Frontier railway whereas Mohanbari Airport is located within the Khagarijan field. Additionally, there are two Air Force bases within the field located at Chabua and Dinjan. Land Lease During the site selection process all the legal requirements will be considered for finalization of surface locations. Once the surface drilling location is finalized, land acquisition will be done including crop compensation. After finalization of drill site, OIL will procure the land from the land owners. The estimated land required per drill site is approximately 2.2 ha. Tentative well coordinates provided by OIL revealed 15 wells within plantation areas of tea garden, 12 wells are located in agriculture land, 2 wells located in household tea garden areas and 1 well within forest land. All the proposed drill sites are away from human habitation; therefore any displacement will not be required for this project. As displacement is not required, resettlement and rehabilitation is not applicable for this project. 1 PROJECT ACTIVITIES This activity involves • Well site preparation, construction of approach roads • Well drilling and testing. • Site closure and decommissioning of wells not indicative of potential hydrocarbon reserves. Site Preparation & Construction Drill site Wells located on the agricultural land have no vegetation; whereas, wells located in the tea garden having tea bushes with shade trees. Site construction work will require clearing of tea bushes and some trees in the drill sites located in the tea garden. Site preparation will involve leveling, filling and consolidation of the site for staging equipment and machinery. Clearance of vegetation is the primary activity that will be undertaken during drill site construction. Following this, top soil will be scraped and stored for future use. The subsequent activities will involve elevating the drill platform by locally available fill material, construction of High Density Polyethylene (HDPE) lined pits for storage of drill cutting, waste mud and drilling wash water, construction of suitable storm water drainage system and construction of approach roads. Drilling & Testing The drilling of wells is expected to be up to a depth of 4500 meters. Standard Land Rig or Mobile Land Rig with standard water based drilling fluid treatment system will be used for drilling. Drill cuttings generated will be collected and separated using a solid control system and temporarily stored on-site in HDPE lined pits (approximately 800 m3 capacity). Drilling and wash wastewater generated will also be stored at an onsite HDPE lined pit. The water will be adequately treated in a mobile Effluent Treatment Plant (ETP) to ensure conformance to the CPCB onshore oil and gas extraction industry effluent standards before disposal. Site closure and decommissioning The drill sites will be properly reclaimed and rehabilitated if no commercial reserve has been established. This process will involve decommissioning of rigs and all machineries; disposal of drilling waste as per CPCB guidelines, disposal of fill materials, top soil restoration. Project Utilities and Resource Requirements Power The power requirement during the site preparation and construction phase for each drill sites will be met through 125 KVA DG sets. Two (2) DG Sets of 1000KW capacity will be required for drilling purposes of which one will be kept as stand by. Lighting and other requirements will be met through 200 KW DG Sets. It is estimated that 3.5 KLD of diesel will be required during drilling phase. 2 Water Total water requirement for drill site preparation and construction phase of the project is estimated to be around 10 KLD. The total projected average consumption of water during drilling phase will be about 40 KLD per well including domestic purposes. Water will be sourced through bore well and permission will be taken from Ground Water Authority regarding abstraction of ground water for industrial purposes, if required. Manpower During the drilling phase, about 50 people will be working per shift. This will include technical experts, who will be responsible for various drilling related activities and some local workmen who will be hired from nearby villages for the entire duration of the project. BASELINE ENVIRONMENTAL STATUS The study of the baseline environmental status helps in assessing the existing environmental conditions and identifying the critical environmental attributes. Baseline environmental study of the Khagarijan Field will comprise study of physical, biological and socio-economic environment where 30 exploratory and developmental wells will be drilled. Primary and secondary data were collected for conduction the EIA study. Physical Environment Climate and Meteorology The study area experiences a humid and warm sub-tropical climate throughout the year except for a cold winter in December till February. Hourly micro-meteorological data collected from primary meteorological station at Tinsukia town during the pre-monsoon reveals that the pre-dominant wind direction is from North West with the wind speed in the range of 1.0-1.5 m/s. Air Quality The ambient air quality representing PM10, Sulfur Dioxide (SO2), and Nitrogen Dioxide (NO2) was monitored at eight different locations for 24 hours twice a week during April- June, 2013.Volatile Organic Carbons (VOCs), Methane (CH4), non-methane hydrocarbons (NMHCs) were monitored at a frequency of once a week for the same period. All the parameters were found to be in compliance to the National Ambient Air Quality Standards (NAAQS), 2009. The average 24 hourly PM10 at the monitoring locations ranged between 3 3 47.38-71.94µg /m (NAAQS-100 µg/m ). The average 24 hourly NO2 at the monitoring 3 3 locations ranged between 13.70-18.27µg/m (NAAQS-80 µg/m ). The average 24 hourly SO2 concentration at 4 locations were found to be Below Detectable Limit (<4 µg/m3) whereas in other stations the average concentration ranged between 4.00-4.50 µg/m3 (NAAQS-80 µg/m3). Average value for methane hydrocarbon ranged between 2.29-2.83 ppm whereas the mean values of non methane hydrocarbon ranged between 0.38-0.75 ppm. Mean values of VOC at all sampling location varies in the range between 1.13-2.33 ppm. 3 Noise Quality The noise quality was monitored for 24 hours at Twenty (20) locations within the Khagarijan Field. Noise monitoring was conducted at areas in proximity to the proposed drill sites. Day time and nighttime equivalent noise levels varied between 50.0-62.7 dBA and 39.4-49.2 dBA respectively. The day time equivalent noise levels at 11 stations out of 20 revealed higher values were compared to the day time noise standards (55 dBA) for residential areas. The night time equivalent noise levels for 4 stations were found to be in exceedance to night time noise standards (45 dBA). Physiography and Geology The Khagarijan Field is included within the depositional plains of the River Brahmaputra and its tributaries. Physiographically, the Field can be classified as Low-lying alluvial belt. Upper Assam Basin is a proven petroliferous basin which represents a classic example of passive continental margin that evolved simultaneously with other east coast basins of India concomitant with rifting followed by drifting of the Indian Plate from eastern Gondwanaland and its subsequent subduction underneath the Burmese and Eurasian plates The basin has thrusted margins on three sides: to the south the Naga Hills Thrust Belt and Manipur Ophiolite Belt; to the east and north the Main Frontal Thrust of the Himalayas, which was active from the mid-Miocene to present day, bends around the Assam Syntaxis. Hydrogeology The annual replenishable ground water sources of Dibrugarh and Tinsukia district as per estimate of CGWB is 1,88,911 hectare metre (ham) and 1,59,036 ham respectively whereas the net ground water availability is found to be 1,79,465 ham and 1,43,132 ham respectively. The stage of groundwater development in Dibrugarh and Tinsukia district is found to be 15% and 12% respectively. Groundwater Quality Groundwater samples were collected and analyzed as per IS: 10500 from Ten (10) locations within the Field. Almost all the parameters analyzed were under the acceptable and permissible limit of IS: 10500.

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