PRE-FEASIBILITY REPORT

Pre-Feasibility Report for Onshore Oil & Gas development drilling and production in -Deohal-Bogapani-Nagajan areain and District,

1.0 PREAMBLE:

OIL LIMITED (OIL), a Government of India Navaratna Enterprise, is currently engaged in carrying out hydrocarbon exploration, development, production and transportation activities in its operational areas in Upper Assam, South-Eastern part of and Mizoram (or Assam, Arunachal Pradesh and Mizoram) in the North Eastern part of India. OIL is also undertaking hydrocarbon exploration activities in few other Indian states and having presence in selected overseas countries.

This EC block covers seven (7) Petroleum Mining Leases (PML) namely Nahorkatiya Extension, Tinsukia Extension, Hugrijan, Chabua, Borhapjan, Dumdumada Hugrijan Extension (Proposed) awarded by Govt. of India and Assam State Govt. to Limited in Dibrugarh &Tinsukia districts for exploration and development of oil & gas.

The area is located in the eastern part of OIL's operational area in Upper Assam Basin. The area covers the established Miocene-Oligocene-Eocene (Tipam-Barail-Lakadong- Langpar) oil and gas fields of Jorajan, part of East Zaloni, Madhuting & Tipling, Makum, Hapjan, Borhapjan, Kusijan, Bogapani, Deohal, Lohali Satellite Fields. The area is extensively covered by seismic surveys, both 2D and 3D. This area contributes to a large extent on the producing fields of Upper Assam basin.

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2.0 LOCATION OF THE NAHARKATIYA-DEOHAL-BOGAPANI-NAGAJANAREA

The Nahorkatiya-Deohal-Bogapani-Nagajan area is located between 95° 13’N to 95° 37’N Longitude and 27° 20’ E to 27° 29’E Latitude as shown in Figure-1.

Figure -1

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3.0 TECHNICAL FEASIBILITY FOR THE NAHARKATIYA-DEOHAL-BOGAPANI- NAGAJANBLOCK:

Geo-scientific works carried out in the block: Geoscientific works were started in early fifties when oil was first established in well No. Nahorkatiya#1 in 1953. This well is not within the NDBN block, however, on the basis of development activities in surrounding this well, Nahorkatiya Extension PML was granted to OIL for further oil exploration. As a result Kusijan (1967), Jorajan (1972), Hapjan (1987), Makum (1993), Jutlibari (1996) Lohali (2002) oilfields were established and presently all are in production stage.

Geophysical Survey:

2D and 3D seismic data acquisition has been extensively carried out in NDBN Block. Initially 2D seismic data was acquired long back from early 1980`s in and around Nahorkatiya and these lines were demarcated as B lines. Part of B lines were also acquired in 1983-1984 in Samdang, Panitolaand Makum areas in 1987-1988. However, acquisition program was defined from mid 80`s to early 90`s. Subsequent to this, 3D seismic data was expansively acquired. 3D surveys lie within the block boundary and some lie in the vicinity of the boundary. Further 3D seismic was acquired in areas of Hapjan (1993-1994), Matimekhana (2005-2006-2007), Jutlibari ( 1997-1998), Madhuting-langkasi( 2012-2013-2014), parts of Digboi-Margherita ( 2009-2010-2011), Borhapjan (1996-1997-1998), Dikom (1995-1996), and Samdang- Kusijan ( 2005-2006-2007-2008).

Exploratory Drilling: Many exploratory wells were drilled in this NDBN Block as a result of which Kusijan, Jorajan, Hapjan, Makum, Samdang, Jutlibari, Lohali, Deohal oilfields were established.

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Technical Assessment & Geological Modeling:

Tiam, Barail, Lakadong+Therria and Langpar in few places (Chabua) are hydrocarbon bearing in this area. Barail is the main contributor from Makum, Hapjan, Kusijan and Jorajan area. Total 15 MMT (2P) has been estimated from the proposed wells in NDBN Block.

Stratigraphy of the North Hapjan-Tinsukia-Dholaarea:

The expected Stratigraphy within the block could be as follows:

AGE FORMATION LITHOLOGICAL DESCRIPTION Present day Alluvium, Older Alluvium and High Level Recent-Pleistocene Alluvium Terraces

Girujan Clay

Miocene Tipam Tipam Sandstone

Barail Argillaceous/Coal Shale Oligocene Barail Barail Main Sand

Kopili Kapili Alternations

Eocene to Upper Narpuh Shale with siltstone Paleocene Lakadong+Therria Glauconitic fine/med grained sandstone and shale

Paleocene Langpar Medium to Coarse grain Sandstone

Precambrian Basement Crytstalline granite,metamorphics.

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Operational Feasibility for Drilling in the Naharkatiya-Deohal-Bogapani-Nagajan area:

The Naharkatia-Deohal-Bagapani-Nagajan (NDBN) Field of Oil India Limited (OIL) covers approximately 657 sq. km area and is located in Dibrugarh and Tinsukia districts of Assam.

The NDBN EC Block is rectangular in shape with its northern boundary more or less aligned with the NH 37 with towns like Tinsukia, Makum and Digboi town mark the eastern boundary of the Field. The southern boundary of the Field extends near to the main course of BurhiDihing, while the western boundary lies in between TingraiChariali and confluence point of Tingrai River with BurhiDihing. The main drainage channels traversing through the Field are within the Tingrai, Tipling and Digboi and are all tributaries of BurhiDihing River. The rivers flow mainly from south- eastern side towards BurhiDihing.

Forest areas within the Field are mostly located at the eastern side (at Tinsukia district) and included primarily under Upper Dihing Reserve Forest. Apart from Upper Dihing R. F., Barjan R. F is also located at the central portion of the NDBN Field. Dehing Patkai Wildlife Sanctuary is located at the south-eastern corner of the block at a distance of 1.7 km from the block boundary. Many tea gardens are present within the Field and are mostly located at the central and western side of the Field. Apart from the commercial tea gardens household tea cultivation is also common in the area.

The Field primarily comprises of rural area with agricultural lands, settlements and homestead plantation. is the major town within the Field. The Field is included under the existing oil and gas producing area of OIL. Apart from OIL facilities, Assam Gas, BCPL etc. also have industrial facilities within the Field. North Eastern Electric Power Corporation Limited (NEEPCO) has a gas based power plant at Bokulani area in the south-central portion of the block.

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Figure: NDBN Field Accessibility Map

The Field can be accessed by NH 37 which connects Dibrugarh and Tinsukia town with the state capital . The eastern portion of the Field and Digboi town can be accessed by NH 38 which branches off from NH 37 near Makum town. Duliajan is the major town within the Block and OIL headquarters, Duliajan is connected with the major towns Dibrugarh, Tinsukia and Digboi by PWD roads. Main settlements, tea gardens, industries and the educational institutions within the Field can also be accessed by PWD roads. However, small villages, remote areas can be accessed by ‘kutcha’ roads.

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The Field is connected with the state capital Guwahati by broad gauge line of North East Frontier railway (Guwahati-Dibrugarh line). Tinsukia, New Tinsukia and Makum are the major junction stations located at the northern boundary of the Field.

Accessibility to the proposed locations:

Motorable village roads are available which may require further re-enforcement prior to preparation of plinth area and carrying out of operational activities. Some of the roads are crossing nallahs, rivulets etc. which will need construction activity to access the identified drilling locations and to make it suitable for mobilization of drilling rig & its associated service packages.

The nearest airport to the Field is located at Mohanbari, Dibrugarh, which is approximately 28 km from Duliajan Town.

Economic Feasibility:

The NDBN EC Block is an established oilfield area and has been contributing to the Nation’s economy. The construction of approach road and well location plinthswill involve some financial expenditure.Based on the undertaken technical study & operational feasibility, OIL is expecting that the Naharkatiya-Deohal-Bogapani- Nagajanto offer a tenable cost- benefit scenario for carrying out the drilling and production activities.

It would be worth mentioning , that the Hydrocarbon vision document 2030 for North East India released in February 2016 jointly by State , Central Government and PSU sectors in North East clearly highlights the need for developing North East Region as a dominant hydrocarbon hub at the forefront of India's energy economy. As a result, Oil & Gas production will be doubled resulting in generation of more employment opportunities, and promote development of manufacturing industries related to Oil & Gas

OIL is committed to supply the feedstock (in terms of gas) to Brahmaputra Cracker Polymer Limited (BCPL)a joint venture of Govt. of Assam, GAIL and OIL, Tea gardens, NTPS , BVFCL, AGCL, NEEPCO, NRL, DNVL and other ancillary industries. It is essential to explore new reserves and develop the existing reserves so that uninterrupted supply of natural gas can be maintained to its customers. These commitment were made after studying the geological reserves in this area considering 20-25 years long production profile, where a number of exploratory and development wells are considered.

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(A.K.Acharya) Chief General Manager (HSE) Nodal Officer (EC/ FC/NBWL) Date:11/11/2017 Oil India Limited Place: Duliajan

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