Internship at bapex

A Report on
Practical Training (Internship) at
Bangladesh Petroleum Exploration and Production Company Ltd.
(BAPEX)
Course Title: Practical Training (Internship)
Course No: GS-503
Submitted by
Md. Shahadat Hossain
Class Roll: 1651
Registration No.: 37524
Session: 2017-2018
Department of Geological Sciences
Jahangirnagar University, Savar, Dhaka-1342

I
Abstract
This Internship report deals with the experience I gathered during my six days long practical training
session at Bangladesh Petroleum Exploration and Production Company Limited (BAPEX). Though the
Internship program is mandatory for partial fulfillment of the M.S. degree of Department of Geological
Sciences, Jahangirnagar University, it has bestowed us with a vast knowledge of practical geosciences.
During the Internship, we were introduced with the three major divisions of BAPEX that are related to
geology background namely Geological Division, Geophysical Division and Laboratory Division. These
three divisions further constitutes some departments and sections to properly balance the huge work load
BAPEX has to deal with. There are some other divisions as well which works in harmony with these three
major divisions.
The Geology Division initiates the primary work of exploration with the aid of their Exploration Geology
Department by operating field work to a particular destination. They usually suggest 2D or 3D seismic
survey lines to the Geophysical Division if any possibility of hydrocarbon is present. 2D or 3D Data
Acquisition Department completes seismic survey and Data Processing Department comes into action
afterwards. Interpretation Department interprets the processed seismic sections and identifies possible
locations of HC entrapment. Basin Study Department and Formation Evaluation Department reveals the
burial history, thermal history, find leads and also suggest potential locations of wells. Development
Geology Department drills wells at the suggested locations and extracts the trapped HC and also discloses
the subsurface geology with the aid of well log or drill cuttings. The Laboratory Division helps the other
divisions with the lab derived data and also examines the samples collected from the already producing
gas fields.
This Internship program was primarily concentrated to demonstrate the sequence of work a petroleum
exploration and production company does. The primary goal of the program was to make the students
familiar with the industry facilities and how giant companies like BAPEX works.

II
Acknowledgement
First of all, I am grateful to Almighty Allah for keeping me safe during the pandemic situation of Covid-
19. Many souls have departed but I am still hale and hearty all because of His grace.
I would like to convey my greatest gratitude to Department of Geological Sciences, Jahangirnagar
University for including such an intuitive course in the curriculum. I have been truly benefitted from this
Practical Training (Internship) course which has definitely encouraged me to devote myself to
geosciences. My deepest appreciation goes to Bangladesh Petroleum Exploration and Production
Company Limited (BAPEX) for warmly welcoming us to their niche and making all the arrangements
that are needed to fulfill our requirements.
I am thankful to Professor Dr. Syeda Fahliza Begum, Chairman, Department of Geological Sciences,
Jahangirnagar University for making this happen. Her true dedication and wisdom were the main reasons
behind the successful completion of this Internship program even in this pandemic situation. My humble
respect goes to S. A. M. Merajul Alam, Deputy General Manager, Geological Division, BAPEX for
coordinating the entire Internship program on half of BAPEX and making us so comfortable throughout
the program.
I express my deepest appreciation to Mr. Nahid Hasnat, Manager (Geological Division); Md. Tariqul
Alam Bhuiyan, Manager (Geological Division); Mr. Saman Uddin Ahmed, Manager (Geological
Division); S. M. Monir Hossain, Manager (Geological Division); Md. Abdul Mumin, Deputy Manager
(Geological Division); Md. Alamgir Kabir, Deputy Manager (Geological Division); Md. Hasan Latif,
Manager (Geophysical Division); Md. Nijam Uddin, Deputy Manager (Geophysical Division); Hawladar
Ohidul Islam, General Manager (Laboratory Division); Wahid Mia, Deputy General Manager (Laboratory
Division); Md. Asif Iqram Khan, Manager (Laboratory Division); Most. Shahanaj Hossain, Manager
(Laboratory Division) and Sabiha Chowdhury, Manager (Laboratory Division) for their valuable classes,
advice and also for managing their time to share their vast experience with BAPEX.
Finally, I would like to thank all the staffs of Department of Geological Sciences, Jahangirnagar
University and BAPEX for helping us technically throughout the Internship program. Last but not the
least, I must admit that I am very lucky to have such helpful classmates. They have always been so kind
and have definitely made this journey very smooth.
Md. Shahadat Hossain

III
Contents
Topics Page No.
Abstract I
Acknowledgement II
List of Figures and Tables IV
Chapter-1 (Introduction)
1.1 General
1.2 Objectives
1.3 Learning from the Internship Program
1
1
1
1
Chapter-2 (Description of BAPEX)
2.1 Why BAPEX
2.2 Organogram of BAPEX
2.3 Current Activities of BAPEX
2
4
5
7
Chapter-3 (Description of the Internship Program)
3.1 General
3.2 Detailed Description
3.2.1 Function of the Geological Division
3.2.1 (A) Exploration Geology Department
3.2.1 (B) Basin Study Department
3.2.1 (C) Formation Evaluation Department
3.2.1 (D) Development Geology Department
3.2.2 Function of the Geophysical Division
3.2.2 (A) 2D + 3D Seismic Data Acquisition Department
3.2.2 (B) Data Processing Department
3.2.2 (C) Interpretation Department
3.2.3 Function of the Laboratory Division
3.2.3 (A) Geological Lab Department
3.2.3 (B) Petrophysical Department
3.2.3 (C) Geochemical Department
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11
13
13
13
18
23
31
39
40
46
48
53
53
55
57
Chapter-4 (Conclusion, Limitations and Recommendations) 59
References 61

IV
List of Figures and Tables
List of Figures
Figure No. Figure Name Page No.
2.1 Organogram of BAPEX 5
2.2 BAPEX Board of Directors 6
2.3 Field work of BAPEX at Sitapahar structure, Rangamati, Bangladesh and 3D
seismic survey at Semuang structure
7
2.4 Srikail Gas Field and Begumganj Gas Field 8
2.5 Fenchuganj Gas Field, Saldanadi Gas Field and Semutang Gas Field 9
2.6 Shahbazpur Gas Field and Shahzadpur-Sundalpur Gas Field 10
3.1 Geological Division with its four main departments and major functions 11
3.2 Geophysical Division with its five main departments and major functions 12
3.3 Laboratory Division with its three main departments and major functions 12
3.4 Geological Division with its four main departments and the sections 13
3.5 Method of Geological Field Survey 14
3.6 Preparation of the field work 15
3.7 Tasks during a field work 16
3.8 Final outcome after geological field survey 17
3.9 Lead identification and seismic layout design 19
3.10 Burial history curve 20
3.11 Thermal history curve 21
3.12 Petroleum generation history (Event chart) 21
3.13 Seismic visualization and interpretation (Bright spot, Dim spot, Flat spot,
Polarity reversals, Horizon picking, Faults)
23
3.14 The borehole environment in a drilled well 24
3.15 SP data acquisition and Representation of an SP log 25
3.16 Caliper tool, Representation of a caliper log and Representation of Gamma ray
log
26
3.17 Induction tool, Latero type tool and log presentation 26
3.18 Sonic log tool, Density log tool and Schematic illustration of a Neutron log tool 27
3.19 Cement bond log tools, Representation of CAST-V log and Production logging
tool
28

V
Figure No. Figure Name Page No.
3.20 A rapid interpretation of well log 29
3.21 Perforation, Perforator configuration and Perforation guns 30
3.22 Well profile and casing design, Selection of casing depths based on pore
pressure and fracture gradient and Well prognosis
33
3.23 Bijoy-10 Rig 35
3.24 Cementing units of BAPEX 36
3.25 Mud logging unit 37
3.26 Contents of a well completion report 38
3.27 Geophysical Division with its five main departments and the sections 39
3.28 Sequence of seismic data acquisition 40
3.29 GNSS survey instruments and GNSS survey 41
3.30 GP and SP location stakeout by GNSS RTK 42
3.31 Satellite surveying and positioning 42
3.32 Field data QC operation 43
3.33 Seismic drilling operation and Explosive loading 43
3.34 Field data recording flow chart 44
3.35 Recording operations 45
3.36 SEG data, instantly after taking shot 45
3.37 Seismic data processing steps 46
3.38 Seismic data processing 47-48
3.39 Prestack gather 49
3.40 Seismic data 50
3.41 Horizon picking, Horizon surface and Depth surface 51
3.42 Well head, Well log and zonation 51
3.43 Well to Seismic tie 52
3.44 Proposed well location and target 52
3.45 Laboratory Division with its three main departments and the sections 53
3.46 Apparatus of Sedimentology section under Geological Lab Department 54
3.47 Apparatus of Biostratigraphy section under Geological Lab Department 55
3.48 Apparatus of Petrophysical department 56
3.49 Major instruments of Geochemical Department 58

VI
List of Tables
Table No. Table Name Page No.
3.1 Drilling rigs of BAPEX 34
3.2 Work over rigs of BAPEX 34
3.3 Sensors used in Mud logging 36
3.4 Services provided by the Geochemical Department 57

1
Chapter-1 (Introduction)
1.1 General
An internship is a professional learning experience that offers meaningful practical work related to a
student’s field of study or career interest. An internship gives a student the opportunity for career
exploration and development, and to learn new skills. It offers the employer the opportunity to bring new
ideas and energy into the workplace, develop talent and potentially build a pipeline for future full-time
employees. There is a lot to learn for fresh graduates like us through an internship program. How a true
company works, what is their views regarding the future of such particular field and how a fresh graduate
can nourish the things in him/her, that are needed to cope with the challenges in work space can be learnt
after a successful internship program like this.
1.2 Objectives
An internship provides fresh graduates with a wide range of opportunities. The objectives of an internship
program are to get used to the working environment where he/she may work in the coming days, create a
network with whom one can share one’s views regarding the field of his/her study, it aids to apply one’s
text book knowledge to the real working environment, moreover strengthen one’s resume to showcase
his/her experience to overcome the challenges with a real industry. It also helps students to be rigid about
their future, whether they want to build their career in such field, as real working experiences are
something different which may/may not attract everyone.
1.3 Learning from the Internship Program
There is a saying in geo-science, “Earth is the geologists’ laboratory”. It rectifies the necessity of real life
experience for a geology graduate. In this regard, such internship programs are a must for the students
coming from geology background as learning from the class room will never be successful if students
cannot achieve such practical experiences.
In our country a wide range of companies operate their work related to geo-science. Oil and Gas
Companies like BAPEX work on petroleum exploration and exploitation, Bangladesh Atomic Energy
Commission tries to locate economically valuable mineral resources, Bangladesh Water Development
Board finds exploitable aquifers and supplies fresh water to people and so on. Graduates can engage
themselves in such companies through an internship program and have true experience how finding a new
gas field/aquifer/mineral locus is done, what are the major decisions to be taken, what challenges are
often faced.

2
Chapter-2 (Description of BAPEX)
History and latest brief about BAPEX
Bangladesh Petroleum Exploration and Production Company Limited (BAPEX) is a Bangladesh
government owned company responsible for petroleum exploration and production. BAPEX was
established in 1 July, 1989 by the Government of Bangladesh as the national exploration company
through dissolving the Exploration Directorate of Petrobangla with a view to accelerating oil and gas
exploration activities of the country. BAPEX was transformed into an exploration and production
company in 23 April, 2000 with a view to making it self-reliant. Currently BAPEX is producing 103
MMscf gas daily from its seven onshore gas fields (Saldanadi, Fenchuganj, Shahbazpur, Semutang,
Shahjadpur-Sundalpur, Srikail and Begumganj) contributing to mitigate the increasing gas demand of the
country. Besides, exploration and drilling activities in its awarded areas, BAPEX has also been
conducting drilling and work-over operations to other sister concerns of Petrobangla since its beginning.
(BAPEX website, accessed 1st
July, 2021).
Seismic facilities
BAPEX has been successfully carrying out 2D seismic survey since its inception. Apart from its own
area, BAPEX has conducted geophysical survey for IOCs like Tullow and Chevron under service
contract. In carrying out exploration activities, BAPEX has been using multitude of hardware and
software such as Geoland Software (field lay-out and QC), Secrel 428 XL (acquisition), RTK, GPS,
SOKKIA, Trimble R8GNSS (survey), ProMax, Geocluster (Processing), PETREL (Geological-
Geophysical modeling), Tigress, Hampson-Russel and Geoframe (interpretation), PetroMod (Basin
Modeling), TecLog (Formation Evaluation). Recently, 3D seismic survey including 3D data processing
and interpretation has been successfully carried out by BAPEX with a view to re-evaluating and
developing gas fields of BGFCL, SGFL as well as BAPEX (BAPEX website, accessed 1st
July, 2021).
Drilling facilities
BAPEX has been equipped with four drilling rigs and two workover rigs. In addition, mud engineering,
mudlogging, cementing units are also available. Most other services activities necessary for drilling is
performed by BAPEX with its own equipment and personnel (BAPEX website, accessed 1st
July, 2021).

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Processing unit
The Process Plants are designed and operated by world renowned PLC & DCS (ABB/
SIEMENS/YOKOGAWA) automation technology. Its maintenance department is well equipped with
modern instrumentation, calibration facilities such as HART Communicator, Process Calibrator, NDT
equipment, Gas Detection system, GC, Portable Dew Point Tester etc. (BAPEX website, accessed 1st
July, 2021).
Laboratory facilities
BAPEX has its own Laboratory equipped with modern equipment such as X-Ray Diffractometer (XRD),
Polarizing and Zoom Stereomicroscope, Core Measurement (Porosity & Permeability) System, Core
Photography System, Gas Chromatograph (GC), Carbon-Sulfur Analyzer, Rock Eval, Atomic Absorption
Spectrometer (AAS), Cement Consistometer etc. Gas, condensate and water samples collected from
exploratory/development wells drilled by BAPEX are routinely analyzed in BAPEX Laboratory along
with samples collected from different gas fields of BAPEX. Core, cutting, outcrop and seepage gas
samples are analyzed for important geological data. Obtained data helps to determine reserve of gas fields
and thus plays an important role in exploration and development activities of BAPEX. Well cement
samples are also tested in BAPEX Lab for well cementation job. Besides, BAPEX Laboratory provides
analytical service to other oil-gas companies, IOC, power plants etc. BAPEX has its own core store where
core samples and drill cuttings are stored after analysis (BAPEX website, accessed 1st
July, 2021).
Scope of BAPEX
 Geological Survey and Evaluation
 2D & 3D Seismic Survey
 Drilling and Workover
 Well Services
 Laboratory Services
 Data Management
 Production and Reservoir Engineering
 Civil Engineering
 Joint Venture Cooperation
(BAPEX Annual Report, 2020)

4
BAPEX at a glance
 Year of Establishment: 1 July, 1989
 Incorporated as Public Limited Company (for exploration): 3 April, 1989
 Incorporated as Public Limited Company (for exploration and production): 23 April, 2002
 Manpower: 692 (364 officers and 328 staff)
 Number of Exploratory Wells Drilled:16
 Number of Workover Wells Drilled: 40
 Number of Gas Fields Discovered: 10
 Number of Gas Fields under Production: 7
 Total Recoverable Gas Reserve: 2.4 TCF
 Daily Production: 103 MMscf
 Total Geological Survey: 3096 Line-Km
 Total 2D Seimic Survey: 15621 Line-Km
 Total 3D Seimic Survey: 4070 Square Km
 Number of Drilling Rigs: 4
 Number of Workover Rigs: 2
 Number of Field Laboratory Unit: 3
 Number of Mud Logging Unit: 3
 Number of Cementing Unit: 2
 Address: BAPEX Bhaban, 4 Kawran Bazar C/A, Dhaka-1215, Bangladesh
 Email address: secretary@bapex.com.bd
 Website: www.bapex.com.bd
(BAPEX Annual Report, 2020)
2.1 Why BAPEX
Bangladesh is an energy deprived country and all the gas fields of the country is depleting at a high rate.
To meet the current demand, finding new gas fields is the first and foremost necessity of the Ministry of
Power, Energy and Mineral Resources (MPEMR). Being stuck in such condition, practical training
(internship) program at an oil-gas exploration and exploitation company like BAPEX is beyond
appreciation. BAPEX is the only government owned company responsible for petroleum exploration and
production in Bangladesh and it has left its signature by finding 9 gas fields till now from 7 of which gas

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is still producing. BAPEX is also competing with the foreign companies and has been successful
thoroughly. Bhola North, Srikail, Mobarakpur, Jakiganj are the recent successes of BAPEX. Moreover, it
is lending its service to other companies after meeting its target. BAPEX has all the capabilities needed to
become an IOC (International Oil Company) and the manpower of BAPEX is also well trained. In this
regard, Department of Geological Sciences, Jahangirnagar University, Savar, Dhaka chose BAPEX to be
the destination of our internship program and we are very glad to learn about the real challenges in oil-gas
industry.
2.2 Organogram of BAPEX
The revised organogram of BAPEX was approved on 22 November, 2011 by the board of directors of
BAPEX. The newly approved organogram (Figure 2.1) can be found at BAPEX website in the name of
“Approved organogram and Table of organization & equipment (TOE) of Bangladesh Petroleum
Exploration & Production Company Limited (BAPEX)”.
Figure 2.1: Organogram of BAPEX (Approved organogram and TOE of BAPEX, 22 November, 2011).

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BAPEX Board of Directors
Figure 2.2: BAPEX Board of Directors (BAPEX Annual Report, 2020).

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2.3 Current Activities of BAPEX
During the fiscal year of 2019-2020 BAPEX discovered Sriakail East Gas Field by drilling an exploratory
well with its own rig and manpower. Gas reserve of about 50 BCF has been estimated through DST
operation. After construction of necessary gas line, daily 10-12 MMSCF gas can be supplied to the
national grid. In addition, under bilateral contract, BAPEX with its own rig and manpower, completed
workover of Narsingdi-1 and Titas-9 wells of BGFCL from which 40-45 MMSCFD is being contributed
to the national grid (BAPEX Annual Report, 2020).
93 line-km of geological survey has been conducted in Sitapahar structure of Rangamati (Figure 2.3 A,
B) district during the fiscal 2019-2020. In addition, 200 square km 3D seismic survey has been completed
over Semutang Gas Field and adjoining structures (Figure 2.3 C, D) (BAPEX Annual Report, 2020).
Figure 2.3: (A-B) Field work of BAPEX at Sitapahar structure, Rangamati, Bangladesh; (C-D) 3D
seismic survey at Semuang structure during the fiscal year 2019-2020 (BAPEX Annual Report, 2020).

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Being a Government nominated 10% participatory partner, BAPEX is monitoring the operations of the
Bangora Gas Field in PSC block-9 operated by Tullow Bangladesh (Kris Energy) and other operator Niko
Resources (Block-9) Limited. Currently about 95 MMSCFB gas is being produced from Bangora Gas
Field (BAPEX Annual Report, 2020).
After a long 10 years of legal pleading, the International Center for Settlement of Investment Disputes
(ICSID) proclaimed the verdict in the Niko case on behalf of Bangladesh. The Minister of State for
Power, Energy and Mineral Resources made this announcement through an online press conference on
03/05/2020. It can be recalled that the Canadian company Niko Resources Limited caused 2 consecutive
blow-outs in January and June 2005 due to their negligence while drilling a well in Chattak Gas Field
(BAPEX Annual Report, 2020).
Status of the active gas fields of BAPEX
As mentioned earlier, BAPEX is producing 103 MMSCFD gas from its 7 gas fields namely Saldanadi,
Fenchuganj, Shahbazpur, Semutang, Srikail, Begumganj and Shahzadpur-Sundalpur Gas Field. During
the 2019-2020 fiscal, contribution of about 36.44 BCF gas productions provided BAPEX Tk 315.46 crore
revenue (BAPEX Annual Report, 2020). The current status of the active gas fields are briefed below:
Figure 2.4: (A) Srikail Gas Field; (B) Begumganj Gas Field (BAPEX website, accessed 2nd
July,
2021).
Srikail Gas Field (Figure 2.4 A)
Discovery: 2012
Production commenced: 22 March, 2013
Location: Muradnagar, Comilla
Number of wells: 4
Number of producing wells: 3
Daily production: 35 MMSCF
Types of process plant: Silica gel Dehydration
Capacity of process plant: 60 MMSCFD

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Begumganj Gas Field (Figure 2.4 B)
Discovery: 1977
Location: Begumganj, Noakhali
Number of wells: 3
Daily production: 6 MMSCFD
Types of process plant: Glycol Dehydration
Figure 2.5: (A) Fenchuganj Gas Field; (B) Saldanadi Gas Field and (C) Semutang Gas Field (BAPEX
website, accessed 2nd
July, 2021).
Fenchuganj Gas Field (Figure 2.5 A)
Discovery: 1986
Production commenced: 22 May, 2004
Location: Kulaura, Moulavibazar
Number of wells: 5
Types of process plant: Silica Gel Dehydration
Saldanadi Gas Field (Figure 2.5 B)
Discovery: 1996
Location: Kashba, Brahmanbaria
Number of wells: 4
Semutang Gas Field (Figure 2.5 C)
Discovery: 1997
Production commenced: 5 December, 2011
Location: Manikchari, Khagrachari
Number of wells: 6

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Figure 2.6: (A) Shahbazpur Gas Field; (B) Shahzadpur-Sundalpur Gas Field (BAPEX website, accessed
2nd
July, 2021).
Shahbazpur Gas Field (Figure 2.6 A)
Discovery: 1995
Production commenced: 11 May, 2009
Location: Borhanuddin, Bhola
Number of wells: 5
Capacity of process plant: 2X35 MMSCFD
Shahzadpur-Sundalpur Gas Field (Figure 2.6 B)
Discovery: 2012
Location: Companyganj, Noakhali
Number of wells: 2
(All the status has been gathered from BAPEX website, accessed 2nd
July, 2021)

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Chapter-3 (Description of the Internship Program)
3.1 General
Our six day long internship program was divided between the three main divisions of BAPEX and the
internship program was conducted online using Zoom from 9th
March, 2021 to 15th
March, 2021. Three of
the main divisions of BAPEX related to geology background were introduced to us namely the
Geological Division, Geophysical Division and Laboratory Division. A short account on those divisions
with their departments and main functions are given below:
The Geological Division is divided into four major departments and it look like this including their main
functions-
Figure 3.1: Geological Division with its four main departments and major functions (modified after
Approved organogram and TOE of BAPEX, 22 November, 2011).

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The Geophysical Division is divided into five major departments and it look like this including their main
functions-
Figure 3.2: Geophysical Division with its five main departments and major functions (modified after
The Laboratory Division is divided into three major departments and it look like following including their
main functions-
Figure 3.3: Laboratory Division with its three main departments and major functions (modified after

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3.2 Detailed Discussion
3.2.1 Function of the Geological Division
As mentioned earlier, the Geological Division is divided into four separate departments (Figure 3.1)
which are also sub-divided into some sections for properly acquiring data from the field and maintaining
it. The detailed version of the Geological Division with all of its departments and sections looks like this-
Figure 3.4: Geological Division with its four main departments and the sections (Approved organogram
and TOE of BAPEX, 22 November, 2011).
3.2.1 (A) Exploration Geology Department
Objectives of Geological Field Survey in terms of HC Exploration
 Geological field survey is the direct source of geological knowledge
 To find out hydrocarbon potentiality
 To prepare geological prognosis of an exploratory well

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 To aid the further exploration program. i.e. proposal for seismic survey
 To collect the samples (rock, oil, gas, water etc.)
 Identifying depositional process
 Mitigate geo-hazard during drilling
A Flow chart of the works done during a field survey is given below:
Figure 3.5: Method of Geological Field Survey (provided materials from BAPEX)

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Instruments used for the field survey (Figure 3.6 D)
 Basemap
 Haversack
 Notebook, pencil, pen, scale
 Clinometer
 Hammer
 Pocket lens
 Dilute HCl
 Sample bag etc.
Software used for the field survey
 Google Earth
 Arc GIS
 Rockworks
 Surfer
 Adobe Photoshop
 Adobe Illustrator
 MS Office etc.
Figure 3.6: Preparation of the field work (A) Site selection & Basemap preparation; (B-C) Basecamp
setup; (D) Instruments used during the field (provided materials from BAPEX)

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Figure 3.7: Tasks during a field work (A) Study of the Basemap; (B) Identification of desired
chara/section; (C) Measuring attitude; (D) Sample collection; (E) Effervescence: checking organic
matter; (F) Sedimentary process identification; (G) Drag fold: indicate soft sediment deformation; (H)
Identifying fossils to detect the formation age (provided materials from BAPEX)

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Figure 3.8: Final outcome after geological field survey (A) Plotted Basemap with attitudes, lithology, HC
shows, structural and fossil indications; (B) Structural map of the area; (C) Geological map of the area;
(D) Proposal of 2D seismic lines (provided materials from BAPEX)

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3.2.1 (B) Basin Study Department
Basin modeling is important in petroleum industry in order to answer the following questions-
 Is source rock mature enough?
 When oil/gas has been generated?
 When did traps form in relation to oil/gas migration?
 How much risk is associated with drilling a prospect?
As mentioned earlier (Figure 3.4) Basin study department has two sections, i.e., Prospect evaluation and
well proposal section and Review section.
Prospect evaluation and well proposal section deals with-
 Study of satellite/remote sensing image, geomorphology, gravity data, magnetic data and
identification of a lead.
 Based on information of a lead, design a seismic proposal.
 Seismic interpretation and structure delineation after acquiring data by geophysical division.
 Prospect/geological evaluation.
 Basin analysis, petroleum system analysis, depositional history analysis.
 Risk analysis (source rock, maturation, migration, trap/seal mechanism etc. study).
 Probability of geologic success, if probability is high then going for well proposal.
 After approval of well proposal, demarcation of the location on field.
A standard well proposal contains-
 Surrounding well history/well control
 Detailed seismic interpretation
 Expected lithology
 Target selection
 Temperature, pressure analysis
 Well design
 Reward forecast
 Well prognosis
Review section deals with-
 During and after deilling a well, seismic data matching with well data, VSP data, wireline log
data
 Correlation with surrounding structure/gas field
 Making program for gas field development
 Modeling with different geological and petrophysical parameters

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 Put forward for field appraisal and development program
 Providing maps and technical support to prepare GTO and reserve estimation
 Analyze geologic field report to search new scope of exploration
Figure 3.9: Lead identification and seismic layout design (provided materials from BAPEX)
Software used for Basin study
 Basin modeling/Analysis software-PetroMod
 Geological interpretation and Geological modeling software-Petrel
Basin modeling software provides
 Burial History
 Thermal History
 Petroleum Generation History

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Burial History (Figure 3.10)
Input parameters are-
 Age of the formation
 Thickness of the formation
 Generalized lithologic data
 Age and thickness of the unconformity
Figure 3.10: Burial history curve
Thermal History (Figure 3.11)
Input parameters are-
 Bottom hole temperature data
 Vitrinite reflectance data
 Paleosurface temperature data
Petroleum Generation History (Figure 3.12)
Organic matter (OM) when disseminated and assimilated in bedrock is generally termed kerogen.
Kerogen is classified as follows-
Type-I: Highly oil prone, H/C 1.5 or more Type-II: Both oil and gas prone, H/C 1-1.5

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Type-III: Mainly gas prone, H/C<1.0 Type-IV: considered as dead carbon hence has
no potential to generate HC
Figure 3.11: Thermal history curve (provided materials from BAPEX)
Figure 3.12: Petroleum generation history (Event chart) (provided materials from BAPEX)
Geophysical interpretation and Geological modeling
 Seismic interpretation can delineate closed structures and identify potential subsurface traps
 Seismic visualization and interpretation
 Domain conversion
 Time contour map/Depth contour map

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Imported data in this case are-
 Seismic data (SEG-Y data)
 Wireline log data
 Well tops
 Checkshot data/VSP data
Seismic visualization and Interpretation
Direct Hydrocarbon Indicator (DHI), is a pattern that (Figure 3.13) can ease our way to locate the
presence hydrocarbon in a reservoir. Several types of DHI are-
Bright spots-localized amplitudes of greater magnitude than background amplitude values
Flat spots-nearly horizontal reflectors, possibly indicating a hydrocarbon fluid level within an oil or gas
reservoir
Dim spots-low amplitude anomalies
Polarity reversals-can occur where the cap rock has a slightly lower velocity than the reservoir
AVO-the amplitude of a reflection might increase with the angle of incidence, a possible indicator of
natural gas
Horizon interpretation-by correlating with the potential zones of nearby wells
Fault interpretation-alignment and distribution faults
Geobody interpretation-complex geological features delineation such as channel sands
Domain Conversion
Conversion from time to depth by-
 T-Z curve (Time-depth relation)
 Check shot data
 VSP data
 Velocity model

23
Figure 3.13: Seismic visualization and interpretation (Bright spot, Dim spot, Flat spot, Polarity reversals,
Horizon picking, Faults) (provided materials from BAPEX)
3.2.1 (C) Formation Evaluation Department
Formation evaluation is used to establish the presence of reservoir rock, evaluate potential hydrocarbons
in reservoir and to estimate the volume of hydrocarbon reserves. Evaluation of sub-surface formations
requires the combined effort of geologists, petrophysicists, drilling engineers and geophysicists.
Following data are used to conduct formation evaluation-
 Laboratory fluid property measurements
 Laboratory (rock) physical property measurements
 Drill cuttings descriptions and Mud logs
 Wireline log measurements
 MWD and LWD
 Formation flow tests (DST)

24
Well Logging Techniques
Well logging can be defined as the continuous recording of various physical properties of subsurface
formations against depth in a drilled well, open or cased. It is also known as geophysical well logging.
Some of the major importance of wireline log data are-
 Surface geophysical methods, i.e., seismic, gravity, magnetic etc. are indirect methods for
locating hydrocarbon while the only method to directly answer this questions is to drill a well and
run wireline log.
 To declare a commercial reserve we need porosity, hydrocarbon saturation, thickness of the pay
zone etc. We need idea about the producibility of a reservoir, i.e., permeability. Well log data
provide all the information related to HC reserves and their producibility.
 Among the whole set of data the log data is the most precise, depth controlled, well resolved and
most representative of the in-situ reservoir condition.
The Borehole Environment
The zones of the borehole from the nearest to the farthest (Figure 3.14) in a borehole is mud cake,
flushed zone (where the mud filtrate has almost flushed out the HC and/or formation water, transition
zone (mixture of mud filtrate and formation fluid), uninvaded zone (virgin formation).
Figure 3.14: The borehole environment in a drilled well

25
Types of Logging
Open Hole Logging-Data acquisition after drilling and before putting any casing (i.e., SP, Resistivity,
Dipmeter, Sonic log, Neutron log, Density log, Gamma ray log, Spectral gamma ray log, Calipar log).
Cased Hole Logging-Data acquisition carried out after steel casing has been lowered (i.e., CCL-Casing
Collar Locator, CBL-Cement Bond Log, VDL, CAST-V).
Production Logging-Carried out in cased hole to diagnose production problems (i.e., PLT).
Spontaneous Potential (SP)
It is a measure of naturally occurring electrical potentials between a movable electrode in the borehole
and a fixed surface electrode (Figure 3.15 A). Basic applications are: demarcation of reservoirs from non-
reservoirs and computation of formation water resistivity (Rw).
The interpretation of SP log is pretty straight forward. SP readings against shale are usually straight,
called shale base line. On the other hand, against a thick sandy formation also gives a straight line called
the sand line. The SP may deflect either to left or to the right of the shale base line (Figure 3.15 B).
Figure 3.15: (A) SP data acquisition; (B) Representation of an SP log (provided materials from BAPEX)
Gamma ray log (Figure 3.16 C)
GR is a measure of the natural radioactivity. As the radioactive minerals concentrate in shale, thus shale
and shaly sands are higher in GR readings. On the other hand, sands and carbonates exhibit low values of
GR readings. Basic applications are: lithology determination and estimation of shale volume.

26
Caliper log
It provides information about the borehole size (Figure 3.16 A, B). Caliper log also provides the volume
of cement slurry required for efficient cementation job with knowledge of casing outer diameter.
Figure 3.16: (A) Caliper tool; (B) Representation of a caliper log (C) Representation of Gamma ray log
(provided materials from BAPEX)
Resistivity log
The resistivity tool is considered to be the most important of all the logging tools. It has the ability to
identify hydrocarbon bearing zones from the water bearing zones. Basically there are two families of tools
viz. Induction and Latero.
Induction tool is basically an electromagnetic tool (Figure 3.17 A) which measures formation
conductivity and then converts it into resistivity. On the other hand, the Latero type tool (Figure 3.17 B)
is typically an electrical tool (also known as Galvanic tool) which directly measures electrical resistivity.
Figure 3.17: (A) Induction tool; (B) Latero type tool and log presentation (provided materials from
BAPEX)

27
Sonic log
The sonic tool (Figure 3.18 A) measures the time of transit of a longitudinally propagating compressional
wave through a unit distance of formation. Basic applications are: porosity determination, fracture
detection, permeability estimation, seismic correlation and abnormal formation pressure identification.
Density log
Formation density is the most important measurement for lithology identification and porosity estimation.
It is a radioactive log in which high energy gamma rays are bombarded into formation from a collimated
source and compton scattered gamma rays are recorded by detector placed at a specified distance from the
source on the tool pad (Figure 3.18 B).
Neutron log
Neutron log tool (Figure 3.18 C) responds to hydrogen richness. Water and oil are substantially the same
in hydrogen content but gas is considerably lower. Thus a neutron measurement is often able to
distinguish between liquid and gas saturated intervals.
Figure 3.18: (A) Sonic log tool; (B) Density log tool; (C) Schematic illustration of a Neutron log tool
CCL: Casing Collar Locator
A downhole tool used to correlate depth using known reference points on the casing string. The casing
collar locator is an electric logging tool that detects the magnetic anomaly caused by the relatively high
mass of the casing collar.

28
CBL: Cement Bond Log
Cement bond tools (Figure 3.19 A) measure the bond between casing and the cement placed in wellbore.
The measurement is made by using acoustic sonic and ultrasonic tools. The measurements are usually
displayed on a cement bong log (CBL) in millivolt units/decibel attenuation, or both. Reduction of the
reading in millivolts or an increase in the decibel attenuation is an indication of better quality bonding of
the cement behind the casing to the wall.
Circumferential Acoustic (CAST-V)
In cased hole CAST-V tool provides ultrasonic pipe inspection and cement evaluation can be obtained
simultaneously. Operating over a wide range of downhole environments, the CAST-V tool offers a full
360 degree profile of the borehole (Figure 3.19 B).
Production Logging Tool (PLT)
Production logging tools (Figure 3.19 C) are run in completed wells to ascertain the nature and behavior
of fluids in or around the borehole during production. These logs are used to analyze dynamic well
performance and the productivity of different zones to diagnose problem wells or to monitor wells.
Figure 3.19: (A) Cement bond log tools; (B) Representation of CAST-V log; (C) Production logging tool

29
Log Interpretation: Quick Look
Figure 3.20: A rapid interpretation of well log (provided materials from BAPEX)
Detail Log Interpretation
Detail log interpretation includes-
 Shale volume calculation, Vsh
 Porosity determination, ɸ
 Water saturation calculation, Sw
Shale volume, Vsh
Shale volume from gamma ray log can be obtained by linearly interpolating between the clean sand level
and the shale level. The equation is, Vsh =
GR(log )−GR(min )
GR(max )−GR(min )
Shale volume from the Density-Neutron difference can be obtained by, Vsh =
∅(neutron )−∅(density )
∅neutron (sh)−∅density (sh)
Porosity determination, ɸ
Since the introduction of compensated density and neutron tools, the combination of these two porosity
tools has become the industry standard. The equation is, ∅ = √(
∅𝑛
2 +∅𝐷
2
2
)
Porosity determination from density log, ∅𝐷 =
(𝑝𝐵 −𝑝𝑓)
(𝑝𝑚𝑎 −𝑝𝑓)
Porosity determination from sonic log, ∅𝑠 =
(𝑡−𝑡𝑚𝑎 )
(𝑡𝑓𝑙 −𝑡𝑚𝑎 )

30
Saturation calculation, Sw
Saturation tools are those logging tools which are sensitive to (gas, oil and water) saturation variations.
Formation resistivity, Rt estimated from these tools is used to estimate the uninvaded formation water
saturation, Sw. The hydrocarbon saturation, Sg is then 1- Sw.
Saturation equation in clean sand is obtained by using famous Archie’s equation, 𝑆𝑤𝑛 =
𝑎𝑅𝑤
∅𝑚 𝑅𝑡
Saturation equation in shaly sand is obtained by,
1
𝑅𝑡
=
∅2𝑆𝑤2
1−𝑉𝑠𝑕 𝑎𝑅𝑤
+
𝑉𝑠𝑕 𝑆𝑤
𝑅𝑠𝑕
Perforation
Perforation helps create a hole in the casing through the cement and into the formation to form a channel
for the oil and gas to flow from the producing formation into the wellbore (Figure 3.21 A). Perforating
guns are used to perforate oil and gas wells in preparation for production (Figure 3.21 C).
There is also loss to count if perforation is done wrong i.e., safety, revenue loss, added cost and above all,
damage to reputation. There are 3 C’s to confirm before perforation is done- correlate, correct and
confirm.
Figure 3.21: (A) Perforation; (B) Perforator configuration; (C) Perforation guns (provided materials from
BAPEX)

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Hydrocarbon volume in a reservoir
For a gas reservoir, the volume of gas initially in place, 𝐺𝐼𝐼𝑃 =
43560∗𝐴∗𝑕∗∅∗(1−𝑆𝑤 )
𝐵𝑔𝑖
𝑐𝑢. 𝑓𝑡.
Where, A=reservoir closure area in acres, h=average reservoir thickness in feet, ɸ=average reservoir
porosity, Sw=average reservoir water saturation, Bgi=initial gas formation volume factor and 43,560 is the
acre-ft to SCF conversion factor.
Three of the five variables in equation (h, ɸ and Sw) are obtained from the well logs. The closure (A)
comes from the seismic mapping and/or subsurface geology. The formation volume factor (Bgi) comes
from analysis of rock and fluid measurements.
𝐵𝑔𝑖 = 0.02829 (
𝑧𝑇
𝑃
)
Here, z=gas deviation factor, T=reservoir temperature and P=reservoir pressure.
3.2.1 (D) Development Geology Department
Development geology department mainly deals with drilling new wells and drilling work-over wells.
Now the basic needs of drilling a well are-
 To know the HC potentiality
 Enhance the production from a known well
 To get knowledge about reservoir characteristics
 Learn about source rock potentiality
 Update geological and geophysical information
 Re-evaluate and update structural maps
The basic needs of work-over are-
 Replacing downhole components like tubing, safety valve etc.
 Enhance the production by producing from a different zone
Development geology department also operates-
 Geological Technical Order (GTO)
 Mud logging
 Well site geology

32
 Monitoring of drilling and production
 Submit well completion report
 Also provides geological consultancy service
Geological Technical Order (GTO) comprises-
 Well summary
 Objectives and targets
 Geology of the area
 Stratigraphy and lithology
 Formation pressure and temperature
 Drilling parameters and hazards
 Mud program
 Drilling program
 Coring program
 Mudlogging program
 Wireline logging program
 Formation integrity test (FIT)
 Well profile and casing design
 Cementation program
 DST program
 Laboratory analyses
 Production testing and completion
 Well prognosis
Drilling fluid
In order to drill a well, fluid must be circulated downward through the drill string around the bit and
upward in the annulus. The drilling fluid is usually a liquid, mostly made up of water. Types of drilling
fluids are-
 Water based mud
 Low solid mud
 Oil based mud
 Air, Gas, Mist systems
Functions of drilling fluid are-
 Remove drill cuttings from the borehole.
 Suspend cuttings and weight material in suspension when circulation is stopped.
 Control subsurface pressure.
 Prevent the borehole from collapsing or caving in.
 Protect producing formation from damage.
 Clean, cool and lubricate the drill bit and drill string.
 Seal porous and permeable zones with impermeable filter cake.
 Support part of the weight of the drill string/casing.

33
Casing
Casing is a strong steel pipe used to ensure a pressure tight connection from the surface to the casing
depth. Casing types include: conductor casing, surface casing and production casing. Some important
functions of casing are-
 To prevent the hole from caving in or being washed out
 To prevent contamination of freshwater sands by fluids from lower zones
 To exclude water from the producing formations
 To confine production to the wellbore
 To provide a means of controlling the well
 To provide a flow path for producing fluids
Figure 3.22: (A) Well profile and casing design; (B) Selection of casing depths based on pore pressure
and fracture gradient; (C) Well prognosis (provided materials from BAPEX)
Drill Stem Test (DST)
DST is a kind of temporary, partial completion of the well that provides data on several meters of
producible formation. DST data come from two main sources: the pressure charts and the fluid sample
taken by the tool.

34
Types of Rig
In general there are two types of rig
 Land rigs
 Offshore rigs (Barge, Tender, Jack up, Platform, Semi submersible, Drillship
BAPEX only have land rigs which currently work on land only.
Table 3.1: Drilling rigs of BAPEX
Rig Name Capacity
(HP)
Working
Capacity (m)
Country of
Origin
Year of
Commission
IDECO H-1700
(Mechanical)
1700 3500 USA/France 1984
Gardner Denver E-1100
(El. DC-DC type)
1500 4000 USA 1987
HH ZJ 70 DBS (Bijoy-10)
(El. AC-AC type)
2000 5000+ China 2010
HH ZJ 50 DBS (Bijoy-12)
(El. AC-AC type)
1500 4000+ China 2014
Table 3.2: Work over rigs of BAPEX
Rig Name Capacity
(HP)
Working
Capacity (m)
Country of
Origin
Year of
Commission
ZJ40 DBT (Bijoy-11)
(El. AC-AC type)
1000 5000
3000 (Drilling)
China 2011
XJ 650T 650 Work over China 2019

35
Figure 3.23: Bijoy-10 Rig (A) Rig itself; (B) Well control equipment; (C) Generators; (D) Draw works;
(E) Top drive; (F) Travelling block; (G) Shale shakers; (H) De-sander; (I) Mud pumps, (J) Degasser

36
Cementing unit
Figure 3.24: Cementing units of BAPEX (provided materials from BAPEX)
Mud logging
Operations of a mud logging unit are-
 Measure, monitor and record different drilling parameters
 Gas show and gas composition monitoring
 Collect and examine the cuttings (Figure 3.25 E) to interpret bottom hole lithology of the well
 Preserve the cuttings for further laboratory investigations
 Preparing Master log (Figure 3.25 F)
Table 3.3: Sensors used in Mud logging
Sensor Type Sensor Name
Rig Floor Draw works, Hook load, SPP, Casing pressure, RPM, Rotary torque, Return flow
Pit Sensors Temperature in, Mud conductivity in, Mud weight in, SPM, Mud pit level sensor
Shale Shaker Temperature out, Mud conductivity out, Mud weight out
Gas System Gas trap motor, Dehydration system, Total gas analyzer, Gas chromatograph
Portable sensor H2S gas sensor, CO2/CO gas sensor, Conductivity/resistivity meter, Temperature
and pH meter
Responsibility of a Wellsite Geologist
 Analyzing, evaluating and dscribing formations while drilling, using cuttings, formation
evaluation measurement while drilling (FEMWD)
 Comparing data gathered during drilling with predictions made at the exploration stage
 Advising on drilling hazards and drilling bit optimization

37
 Taking full responsibility for making decisions about suspending or continuing drilling
 Advising operations personnel on-site and in the operations office
 Supervising mud logging, MWD/LWD and wireline services personnel and monitoring quality
control in relation to these services
 Keeping detailed records, writing reports and sending to appropriate departments
 Maintaing up-to-date knowledge of measuring while drilling (MWD) tools, such as gamma and
resistivity, as geosteering becomes increasingly important
Figure 3.25: Mud logging unit (A-B) Work station; (C) Rig floor monitor; (D) Mud logger’s PC; (E)
Cutting samples; (F) Masterlog (provided materials from BAPEX)

38
Figure 3.26: Contents of a well completion report (A) Mud weight vs depth; (B) Well completion time;
(C-D) Time required at different works of drilling (provided materials from BAPEX)

39
3.2.2 Function of the Geophysical Division
As mentioned earlier, the Geophysical Division is divided into five separate departments (Figure 3.2)
which are also sub-divided into some sections for properly acquiring data from the field, interpreting them
and maintaining it. The detailed version of the Geophysical Division with all of its departments and
sections looks like this-
Figure 3.27: Geophysical Division with its five main departments and the sections (Approved
organogram and TOE of BAPEX, 22 November, 2011)
Activities of the Geophysical Division
 Seismic data acquisition (2D and 3D)
 Data processing (2D and 3D)
 Data interpretation and prospect evaluation (2D and 3D)
 Maintenance the equipments
 Providing geophysical services to other organizations (2D and 3D)

40
Objectives of Seismic Survey
 To identify leads and prospects
 To enhance accuracy in delineating complete structural and stratigraphic maps
 Delineate the exact areal distribution of the existing pay sands
 Identify new pay sands
 Provide authentic idea about the in place hydrocarbon volume
 Mark locations for appraisal, development and exploratory wells
 To identify future exploration targets
Software and Equipments used
 Surveying-Trimble R8 GNSS, Trimble S6 Total Station, GP Seismic Software
 Design & QC-Geoland Software, Field Geovation
 Drilling-Honda/Butterfly Hand Rotary Machine
 Recording-Sercel 428XL, Sercel 508
 Processing-Geovation Software, CGG
 Interpretation-Petrel, Techlog, Tigress, Basin Mod, OpendTect, Hampson Russel
For our convenience, the 2D and 3D Seismic Data Acquisition departments are described in a single
section.
3.2.2 (A) 2D + 3D Seismic Data Acquisition Department
Figure 3.28: Sequence of seismic data acquisition (provided materials from BAPEX)

41
Surveying section
Figure 3.29: (A) GNSS survey instruments; (B) GNSS survey (provided materials from BAPEX)

42
Figure 3.30: GP and SP location stakeout by GNSS RTK (provided materials from BAPEX)
Figure 3.31: Satellite surveying and positioning (provided materials from BAPEX)

43
QC Section
Figure 3.32: Field data QC operation (provided materials from BAPEX)
Drilling section
 Collect survey sketch, SP locations from survey section
 Collect drilling program from QC section
 Drilling on SP locations using Water Flash Drill system
 Loading explosives in drill hole
Figure 3.33: (A) Seismic drilling operation; (B-C) Explosive loading (provided materials from BAPEX)

44
Recording section
Figure 3.34: Field data recording flow chart (provided materials from BAPEX)
Recording instruments and software
1. 428 XL Line Control Interface
2. 428 XL Server 4000
3. 428 XL client computer
4. e-428 software
5. 408UL Line acquisition unit (LAUL)
6. 428XL crossing line acquisition unit (LAUX)
7. FDU (Field Digitizer Unit)
8. Geophone
9. Hydrophone etc.

45
Figure 3.35: Recording operations (A) FDU link cable test; (B) Repair of cutting cables; (C) Repairing
bad FDU; (D) Geophone test by GT-7010; (E) Cable leakage test; (F) Stacked cable and geophone; (G)
Carrying geophone and cable for layout; (H) Shooting and recording; (I) Carrying recording device
Figure 3.36: SEG data, instantly after taking shot (provided materials from BAPEX)

46
3.2.2 (B) Data Processing Department
Data acquired from the field are prepared for processing by the field party itself and then it is send to the
processing center. Processing is required because the data collected from the field is not a true
representation of the subsurface.
Software used
 ProMAX
 SeisSpace
 Geocluster
 Geovation
 CGG
Seismic data processing procedures
Figure 3.37: Seismic data processing steps (provided materials from BAPEX)

47
Figure 3.38: Seismic data processing (A) Reformatting SEG data; (B) Velocity analysis (provided
materials from BAPEX)

48
Figure 3.38: Seismic data processing (A) First break picking; (B) Static correction model; (C) Migrated
stack (provided materials from BAPEX)
3.2.2 (C) Interpretation Department
Objectives of seismic data interpretation
 Structural and Stratigraphic mapping
 Well to seismic tie
 Identification of new prospect

49
 Delineation of lateral distribution of the existing pay sands
 Attribute analysis for HC detection
 Locating optimum locations for exploration and development wells
Workflow
 Seismic data loading
 Well data loading
 Petrophysical analysis
 Well to seismic tie
 Horizon picking
 TWT mapping
 Velocity modeling
 Depth conversion
 Advanced interpretation (Attribute
analysis, AVO modeling and analysis)
 Prospect identification
 Reserve estimation
 Development planning
Required data
 Seismic data 2D/3D
 Well data
 Geological information
 Production data
 Cultural data
Figure 3.39: Prestack gather (provided materials from BAPEX)

50
Figure 3.40: Seismic data (provided materials from BAPEX)

51
Figure 3.41: (A-B) Horizon picking; (C) Horizon surface; (D) Depth surface (provided materials from
BAPEX)
Figure 3.42: (A) Well head; (B) Well log and zonation (provided materials from BAPEX)

52
Well to Seismic tie workflow
 De-spike of sonic log using median filter
 Sonic log calibration by check shot data
 Wavelet extraction
 Generation of synthetic trace
 Match synthetic trace with seismic trace
Figure 3.43: Well to Seismic tie (provided materials from BAPEX)
Figure 3.44: Proposed well location and target (provided materials from BAPEX)

53
3.2.3 Function of the Laboratory Division
As mentioned earlier, the Laboratory Division is divided into three separate departments (Figure 3.3)
which are also sub-divided into some sections. The detailed version of the Laboratory Division with all of
its departments and sections looks like this-
Figure 3.45: Laboratory Division with its three main departments and the sections (Approved
organogram and TOE of BAPEX, 22 November, 2011)
Role of BAPEX Laboratory Division
 Sedimentological analysis for depositional environment, mineral composition and petrography
 Microfossil identification for age and depositional environment identification
 Gas, water and condensate analysis for chemical composition
 Core analysis for reservoir characterization
 Geochemical analysis of core, cutting and outcrop
 Cement analysis for well cementation job
 Provide laboratory service for other organizations
 Support university students in analysis of their samples for research
3.2.3 (A) Geological Lab Department
It consists of Biostratigraphy and Sedimentology Section where core, cuttings and outcrop samples are
analyzed.

54
Sedimentology section
Three major works are done-
 Grain size analysis-for determination of paleo-environment
 Petrographical analysis-to identify minerals, textural properties and diagenetic properties
 XRD analysis-to determine mineral composition, specially clay minerals
Figure 3.46: Apparatus of Sedimentology section under Geological Lab Department (A) Vibro shaker for
sieving; (B) Rock cutter; (C) Rock polisher; (D) Petrographic grinder; (E) Polarizing microscope; (F-H)
Thin section under microscope; (I-J) Sample preparation for XRD analysis; (K) Rigaku Ultima IV XRD
Biostratigraphy section
Micropaleontological analysis is done for the determination of-
 Age of the formation
 Depositional environment of the formation

55
Figure 3.47: Apparatus of Biostratigraphy section under Geological Lab Department (A) Sample
grinding by mortar and pestle; (B) Sieve set for collecting sample; (C) Olympus microscope; (D-G)
Microfossils under microscope (provided materials from BAPEX)
3.2.3 (B) Petrophysical Department
Petrophysical department provides core analysis to determine petrophysical properties of rock. During
core analysis the following areas are covered-
 Core photography-1) Visual documentation of core, 2) Photographed under either white or UV
light, 3) UV highlights the oil stain or fluorescence
 Slabbing-Core is slabbed to prepare core plug
 Plugging-Core plug is representative small form of whole core with plug size of 1 and 1.5 inch
diameter
 Cleaning-Core plug is cleaned to remove unwanted material at Soxhlet extractor and Dean-Stark
apparatus
 Drying-Cleaned core plug is dried to remove solvent
 Porosity-Measure of storage capacity of a reservoir
 Permeability-Flow capacity of rock
 Fluid saturation-Two methods are followed: 1) Dean-Stark method, 2) Core retort method
 Resistivity-Measured at 100% brine saturated core
 Data compilation
 Reporting

56
Figure 3.48: Apparatus of Petrophysical department (A-C) Core photography; (D) Core slabbing
equipment; (E) Core plug samples; (F) Core cleaning apparatus; (G-H) Core drying; (I-J) Apparatus for
determining fluid saturation; (K) Resistivity meter (provided materials from BAPEX)

57
3.2.3 (C) Geochemical Department
Provides laboratory services in four different areas (Table 3.4)-
Table 3.4: Services provided by the Geochemical Department
Geochemical
Department
Exploration &
Development
Services
Analysis of outcrop samples collected by geological field
party for source rock evaluation
Analysis of seep gas/oil samples
Analysis of gas/liquid HC/water collected from exploratory
wells
Analysis of core cutting samples collected from drilled wells
Drilling Services Testing of cement for well cementation
Analysis of drilling materials
Production
Related Services
Analysis of monthly routine gas/condensate/water collected
from production wells
Analysis of glycol/water/oil samples
Analytical
Services
Provides laboratory services for many organizations such as
TGTDCL, SGFL, BGFL, Niko Resources (BD) Ltd., Tullow
Bangladesh Ltd. etc.

58
Figure 3.49: Major instruments of Geochemical Department (provided materials from BAPEX)

59
Chapter-4 (Conclusion, Limitations and Recommendations)
Conclusion
It is beyond doubt that we are very lucky to have a practical training course, moreover at such an active
hydrocarbon exploration and production company like BAPEX. Geology is a subject which is solely
depended on applying the classroom knowledge into on field tasks and this internship program has
directly shown us how to do so. This internship program has aided us to focus in areas where we have to
build our skills as a graduate student and we are also very lucky to find some mentors at BAPEX with
whom we can discuss time to time regarding any inquiry about field geology.
This program has also demonstrated how such a large company works in a group with a view to exploring
new prospects and evaluating that as well. The geological field party from the Geological Division kick
starts the initial work, matches string to string and suggests Geophysical Division where to conduct 2D or
3D seismic survey. The Geophysical Division submits their work and the Basin Study Department
analyzes the interpreted seismic sections, interprets well logs, estimates the reserve volume and selects a
location to drill. Finally the Formation Evaluation Department drills well to explore the subsurface
hydrocarbon in order to supplying it to the national grid. The Laboratory Division is always present there
to support all the divisions and the departments to analyze field samples whether oil/gas/water in order to
keep the exploration work going. BAPEX is so much successful till date because of their collaboration
with every sections and departments. It will be helpful for the future students as well, if such internship
programs are arranged in order to prepare the future geo-scientists for the nation.
Limitations
 The first and the foremost limitation of the internship program is that it was conducted online
using Zoom meeting platform because of the Covid-19 pandemic. A practical training course like
this without visiting laboratories and without having a firsthand experience is not so fruitful to be
honest.
 As the program was conducted online, internet issue was a big drawback from both the students’
and the trainers’ side.
 BAPEX is a huge company and it has so many departments and divisions. It is very hard to keep
pace with learning about all the departments in such a small duration of six days only.
 Last but not the least, an internship program creates a beautiful relationship between the students
and the industry personnel. As the program was conducted online many of us has failed to create
such a magical bonding.

60
Recommendations
 The duration of the internship program should be increased. A practical training of at least a
month can truly help the fresh graduates to be familiar with the petroleum industry.
 As BAPEX is a production company as well, field visit to a producing gas field or visit to a drill
site can be included in the internship program as well.
 Students can also be divided into two/three groups to have the internship program at different
institutes. We can share our gathered knowledge with each other regarding the different
organizations.
 Last of all, an appreciation certificate should be awarded to the students after successfully
completing the internship program by the organization that operates it. It will obviously increase
one’s interest for the program and students can also add this achievement to their Curriculum
Vitae (CV).

61
References
BAPEX website (www.bapex.com.bd), accessed July, 2021.
BAPEX, 2011. Approved Organogram and Table of Organization & Equipment (TOE) of BAPEX.
BAPEX, 2020. Bangladesh Petroleum Exploration and Production Company Limited (BAPEX) Annual
Report.
BAPEX, 2021. Provided Materials for the Practical Training (Internship) Program.

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