Pre-Feasibility Report for Onshore Oil & Gas development drilling and production in Dibrugarh – Bhogpara area

1.0 PREAMBLE:

OIL INDIA LIMITED (OIL), a Government of India Navaratna Enterprise, is

currentlyengaged in carrying out exploration, development and transportation

activities in its operational areas in Upper Assam, Arunachal Pradesh and Mizoram

in the North Eastern part of India for petroleum exploration. OIL is also

undertaking hydrocarbon exploration activities in few other Indian states and few

overseas countries.

Govt. of India and Assam awarded Petroleum Mining Lease (PML)for exploration

and development of oil & gas inDibrugarh, Chabua, Hugrijan and Tinsukia

adjoining areas to Oil India Limited inDibrugarhdistrict.

The area is a part of greater Tengakhat area in the Central Basement High and is

located in Central part of OIL’s operational area of Upper Assam. 3D seismic

surveys were carried out extensively in the block. The 3D surveys includes Parts of

Dibrugarh and Bhogpara areas covering parts of Central Basement High (CBH). All

the wells have been drilled within the Blocks mainly for Palaeocene/Eocene

[Lakadong+Therria (LK+TH) &Langpar] prospects. The area nearby involves the

established oil and gas bearing structures viz. Bhogpara, Dikom, Kathaloni,

Sealkati, Tamulikhat, South-Kathaloni, Tengakhat which are primarily producing

from Lakadong+Therria reservoirs and Moran and Shalmari areas which are

producing from both Barail and deeper Lakadong+Therria reservoirs. There also

exists some marginal satellite fields Diroi, Borbil, Dholiya in close proximity to the

area. Seismic interpretation of 2D and 3D led to identify structures of Namdang,

Telpani, Lejai, Sologuri-East and Sologuri West to probe Paleocene-Lower Eocene

prospects in the area. Oil was discovered in Sologuri-1 in Lakadong+Therria

Formation and presently under production.

2.0 LOCATION OF THE DIBRUGARH BHOGPARA BLOCK

The Dibrugarh-Bhogpara area for land drilling operations by OIL is bounded by the geographical co-ordinates, 94°50'60.00" E - 95° 04'60.00"E Longitude and 27°32'0.00"N - 27°18'0.00"N Latitude (Dibrugarh District) and extends over 597 Sq km.

Block Co-ordinates

Block Coordinate

A 94°50'60.00"E 27°32'0.00"N Dibrugarh-Bhogpara B 95° 04'60.00"E 27°32'0.00"N Dibrugarh-Bhogpara C 94°50'60.00"E 27°18'0.00"N Dibrugarh-Bhogpara

D 95° 04'60.00"E 27°18'0.00"N Dibrugarh-Bhogpara

3.0 TECHNICAL FEASIBILITY FOR THE DIBRUGARH BHOGPARA BLOCK:

Geo-scientific works carried out in the block:

Concept of carrying out Geoscientific work in this part of Brahmaputra valley was

started when Government of India awarded OIL exploration license (PEL) for an

area of 1230 Sqkm in 1987. Mainly seismic work was carried out and has been

described in below para. After acquisition, the seismic data were processed and

interpreted for understanding the geological model and generation/entrapment of

hydrocarbon potential in this area. Geophysical Survey:

Seismic survey was initiated with 2D acquisition (DB lines) when the area was

under Dibrugarh PEL. Bhogpara structure was proved to be oil bearing in 1998

and subsequently 3D seismic acquisition was extensively carried out in the area. At

different times, this part was overlapped under seismic acquisition as follows :

approx. 206 Sqkm in the year 2008-2009 with 25*50 bin size orthogonal geometry,

Bhogpara area approximately 126Sqkm (2000-2001-2002, 25*50 bin size),

Sologuri-Borbam acquisition around 623 sqkm areas (2008-2009, 180 split spread,

25*50 bin size), in the vicinity of Haldibari & Dikharipathar, 478 sqkm (2005-06 &

2009-10). It appears that the area is fully covered with recent seismic data.

Exploratory Drilling:

Exploratory drilling was started in 1997-98 in Dibrugarh-Bhogpara EC Block when

oil was discovered at well No. Bhogpara-1. Subsequently, the field was developed by

drilling another 19 wells. 95% wells were successful for producing oil and gas.

Further south of this Bhogpara oilfield, two more exploratory wells Namdang-1

(2008) and Sologuri-1 (2013) were drilled. Sologuri-1 well was successful and

presently under production of oil @ 20 klpd. Namdang-1 well could not be probed

as a commercial oil producer due to poor hydrocarbon prospects.

Technical Assessment & Geological Modeling:

Dibrugarh-Bhogpara EC block is a highly prospective area from oil production

point of view. It has been contributing to the state economy since Januray 1998

with an average crude oil production of 500 KLPD and gas 50 MSCUMD. So far

Bhogpara oilfield has produced 3.3 MMT crude oil and gas 0.35 MMSCUM. It is

expected that the new exploratory wells will add more oil/gas with further drilling

in this area.

Stratigraphy of the Dibrugarh – Bhogparaarea:

The expected Stratigraphy within the block could be as follows:

AGE FORMATION LITHOLOGICAL DESCRIPTION

Recent-Pleistocene Alluvium

Present day Alluvium, Older Alluvium

and High Level Terraces

Plio-Pleistocene Dihing Dhekiajuli beds in Upper Assam Valley

Mio-Pliocene Dupitila Namsang Beds in Upper Assam Valley

Miocene Tipam

Girujan Clay

Tipam Sandstone

Surma Not subdivided

Oligocene Barail

Barail Coal Shale

Barail Main Sand

Eocene

Disang

Jaintia Group

Kapili Alternations

Sylhet Limestone

Cretaceous: Danian, Maestrichtian and Lower Precambrian Basement

Langpar Formation

Mahadek Formation

Operational Feasibility for Drilling in the Dibrugarh – Bhogparaarea: The Dibrugarh – Bhogparaarea is located in the western part of the OIL’s

operational area in Assam. The identified Locations fall mostly in Dibrugarh,

Chabua, Hugrijan, Tinsukia and a little bit in Dholiya PMLs in the Dibrugarh

District which is located in the north eastern corner of the Upper Brahmaputra

valley. A major part of the extensive plain is formed by the Brahmaputra and its

major south bank tributary-the BuriDihing. Dikom/Bhogpara can be considered as

the central location of the area. Dikom is located at the extreme eastern border of

the area and Bhogpara is located roughly in the middle. The major rivers within the

area are the Brahmaputra and the BurhiDihing. Agriculture is the primary source

of the livelihood of the rural population, while in the urban areas; people are

absorbed in different occupations.

Nearest railway station is at Dibrugarh, headquarters of the Dibrugarh district in

the state of Assam in India. Well known as the Tea City of India, Dibrugarh is

considered to be a major city in eastern India in line with Guwahati and is the

emerging communication and industrial hub of North East India. Dibrugarh is well

connected to the rest of India by rail, road and air transport and thus serves as a

gateway to eastern Assam and also parts of Arunachal Pradesh. Dibrugarh is

considered as an economic hub of North East region of India being at the centre of

economic activities dominated by the Oil and natural gas, tea production, tourism,

power generation, fertilizers and cottage industry. Major industries in and around

Dibrugarh are Oil India Limited, headquarter at Duliajan and ONGCL, Nazira office

at Sivagar engaged in exploration and transportation of crude oil and natural gas,

Assam Gas Company Limited (AGCL), Brahmaputra Cracker and Polymer Limited

(BCPL), BVFCL (Brahmaputra Valley Fertilizers Corporation Limited), NEEPCO

(North Eastern Electricity Power Corporation Limited) etc.

Figure: Road & Rail map of Dibrugarh Town to Lohoal Town (in Dibrugarh-Bhogpara Block)

Road map

Rail Map

The proposed locations are on an average 50 km from Dibrugarh. The distance between Dibrugarhand Bhogpara by road is about 49 km and nearest railway station at Dibrugarh and Moranhat etc.

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. Dibrugarh Airport will be within10 km from Bhogpara area. Economic Feasibility: The constructions of approach road to the identified locationswill involve some financial expenditure. OIL is still in the process of carrying out the further detailed Techno-Economic analysis for the said area based on the acquired geo-scientific information. However, based on the undertaken technical study & Operational feasibility, OIL is expecting that the Dibrugarh Bhogpara area is expected to offer a tenable cost- benefit scenario for carrying out the drilling and production activities.

Date: 18.09.2017

(A.K.Acharya)

Place: Duliajan General Manager (HSE) & Nodal Officer (EC/FC/NBWL) Oil India Limited