Executive Summary English
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Environmental Impact Assessment Report for the proposed Exploration, Development and production in 5 onshore PML blocks in Assam Arakan Fold Belt (AAFB), Assam & Assam Arakan (A & AA) Basin, Cachar District and Karimganj District, Assam Executive Summary 1.0 INTRODUCTION Oil & Natural Gas Corporation Limited (ONGC) is the largest crude oil and natural gas producer in India, contributing around seventy five percent to Indian domestic production. Crude oil is the raw material used by downstream companies like IOC, BPCL, and HPCL (subsidiary of ONGC) to produce petroleum products like Petrol, Diesel, Kerosene, Naphtha, and Cooking Gas-LPG. ONGC has proposed exploration, development and production activities in the envisaged prospects for hydrocarbon falling in 5 PML blocks identified through seismic surveys. The PML blocks lie within the “Assam Arakan Fold Belt” (AAFB) falls in the Assam-Arakan Basin, Cachar and Karimganj Districts, Assam. The area covered in PML blocks identified as project area is presented below: Block Name Area (Sq. Average Depth (meter) Km) Banskandi PML 15.0 2500-4000 During exploration stage Bhubandar PML 6.0 & 2,500 m for development wells. Sector VC PML 497.0 Adamtila PML 4.0 Adamtila Extension PML 148.0 1.1 Project Location Study area of the project is divided into two separate units based on the relative distance between and nearness of PML blocks as well as nearest IMD meteorological stations. While, Banskandi PML, Bhubandar PML and Sector VC PML are covered in one unit (Study Area-I) (covered in Cachar District); Adamtila and Adamtila Extension PML are covered in another unit (Study Area-II) (covered in Karimganj District). The Study Area-I in Cachar district has the nearest IMD meteorological station at Silchar, within the Sector VC PML and in Study Area-II, the nearest IMD meteorological station is located at the Kailasahar Airport in Tripura state. The environmental settings of the area within and from the block boundary (10 km radius), name of the PML/ML areas where well drilling is proposed and the area covered within the 10 km radius from the project area block boundary is explained in the detail in Chapter- 1 of the report. The project area has mixed land use type with agricultural land and surface water bodies contributing to dominating surface features. Silchar is the most important urban center which also consist of the nearest accessible airport. The study area maps of the project are presented below: VIMTA Labs Limited, Hyderabad EE-1 Environmental Impact Assessment Report for the proposed Exploration, Development and production in 5 onshore PML blocks in Assam Arakan Fold Belt (AAFB), Assam & Assam Arakan (A & AA) Basin, Cachar District and Karimganj District, Assam Executive Summary STUDY AREA - I STUDY AREA MAP OF 10 KM RADIUS FROM THE BLOCK BOUNDARY (BANSKANDI PML, BHUBANDAR PML AND SECTOR VC PML VIMTA Labs Limited, Hyderabad EE-2 Environmental Impact Assessment Report for the proposed Exploration, Development and production in 5 onshore PML blocks in Assam Arakan Fold Belt (AAFB), Assam & Assam Arakan (A & AA) Basin, Cachar District and Karimganj District, Assam Executive Summary STUDY AREA - II STUDY AREA MAP OF 10 KM RADIUS FROM THE BLOCK BOUNDARY (ADAMTILA PML AND ADAMTILA EXT. PML) VIMTA Labs Limited, Hyderabad EE-3 Environmental Impact Assessment Report for the proposed Exploration, Development and production in 5 onshore PML blocks in Assam Arakan Fold Belt (AAFB), Assam & Assam Arakan (A & AA) Basin, Cachar District and Karimganj District, Assam Executive Summary 1.2 Project Description ONGC plans to undertake exploratory drilling (in 33 Wells) and later development wells to be established based on the commercial viability of the Hydrocarbon reserves in the respective PML blocks. Based on discovery of the hydrocarbon reserves, the Bhubandar PML fields will be connected to Banskandi-Bhubandar Pipeline. This Banskandi-Bhubandar pipeline will be connected to Banskandi GCS. Development wells for Northern part of Banskandi and Sector VC PML Blocks will be connected to EPS located at North Banskandi area which is currently under production. The development wells from Adamtila and Adamtila Extension PML will be connected to Adamtila GCS which is currently under production. No additional facility is planned to be constructed except connecting the development wells to the existing facilities. The site preparation followed by establishment of exploratory wells will commence after identification of drill site within the PML boundary. Site configuration and the target drilling depth is explained in detail in Project Description (Chapter 2) of this report. Water Based Mud (WBM) will be used in exploratory drilling, but use of Synthetic Oil Based Drilling Mud (SOBM) may be require due to the complexities associated geological formations and associated hole stability problems. At the end of the drilling SOBM will be recycled completely and reused in subsequent drilling operations. Each Drill site will require about 3 DGs running continuously (rating 1500 KVA/DG) for operations. About 30-40 people would access each drill site during exploration phases. The net water requirement will be in the range 25 m3 (includes process requirement and domestic requirement) at each drill site during the exploration phase. The land requirement at each site will be in the range of 1.1 ha which will be leased for the drilling phase in the land acquisition process. If required, the approach road to drill sites will be constructed/ upgraded by the PWD to provide access for the drilling equipment and construction machinery and material, supply vehicles, passenger vehicles etc. The basis of the operational philosophy is that the activities proposed in oil & gas processing shall be operated in complete compliance with all applicable Laws, Regulations, Standards and Permits, the Production Sharing Contract (PSC), ONGC corporate policies, procedures, specifications, rules, standards and guidelines. In order to achieve this, the proposed drilling sites will be maintained by technically qualified and experienced people. Detailed procedures and plans will be developed for each activity prior to operations start up. All persons on board the drilling rig will be part of an experienced crew with valid qualifications. 1.3 Description of Environment The project area is drained by Barak river and its tributaries like Chri river, Sonai river, Rukini river etc. drain the project area in Cachar district while, Longai river and Juri river drain the project area in Karimganj District. Patches of Barail and Jiri reserve forests (RFs) were discovered within the Sector VC PML and patches of Sonai RF is observed within Bhubandar PML in Cachar District. Patches of Longai RF and Tilbhum Hill RF are marked within Admatila Extension PML. No major industrial activities were found within the study area though. VIMTA Labs Limited, Hyderabad EE-4 Environmental Impact Assessment Report for the proposed Exploration, Development and production in 5 onshore PML blocks in Assam Arakan Fold Belt (AAFB), Assam & Assam Arakan (A & AA) Basin, Cachar District and Karimganj District, Assam Executive Summary Soil sampling was conducted covering different land use patterns include, forest lands, open lands, agricultural lands, etc. As per the standard soil classification described in ‘Hand Book of Agriculture, Indian Council of Agricultural Research’ it is observed that the soil in the project area is mostly characterized by moderately acidic to moderately alkaline in nature. The NPK values were also found to be ranging from less to sufficient indicating that the soil quality is suitable for agriculture and cultivation. On-site monitoring was undertaken for various meteorological variables in order to generate the site-specific data. When the meteorological data generated at the monitoring site was compared with the data recorded at nearest IMD station Silchar/Kailashahar(A), it was observed that the data generated at the site is broadly in comparison with regional meteorology, except for minor variations. The ambient air quality of the project area is reported through primary ambient air quality monitoring conducted in non-monsoon season, covering post-monsoon season and partly winter season of 2019. The AAQ monitoring was conducted within the period starting from 1st October 2019 to 31st December 2019. The ambient air quality thus conducted within study area confirms that all parameters monitored (as per NAAQS and additional parameters) are within permissible standards. The ground water and surface water monitoring were conducted in several locations covering the study area. Only iron and magnesium were found to be exceeding in a few locations when compared with IS standards for drinking water. Noise monitoring is conducted in several locations covering such areas as silent zones near schools and hospitals, commercial areas, residential areas, rural and urban areas etc. The noise levels were found to be within permissible limits at all locations. The project area is characterized by tropical rainforest type flora and fauna. The study areas flora and fauna is ecologically rich and also it is fragmented with agriculture fields and habitations. Tea plantations are also observed more regularly unlike other agricultural crops. The village wise demographic data of 764 villages, 02 census towns in Cachar district, 364 villages in Karimgung district, 34 villages, 01 census town and 09 Nagara Panchayat in North Tripura district, was collated as 2011 Census data of India. The project area (PML Block area) is distributed in above areas of the Cachar, Karimganj and North Tripura district. The detailed demographic structure and socio- economic pattern of the project study area is explained in detail in Chapter 3 of this report. 1.4 Assessment of Impacts and Mitigation Measures The proposed exploratory drilling of wells project is a short duration activity at each well location, typically encompassing a period of 3-4 months from land acquisition to site abandonment. The impact would therefore be localized, temporary and minimal. Because of the above activities, the topographical structure may change locally.