A TECHNICAL REPORT

ON
STUDENT’S INDUSTRIAL WORK EXPERIENCE SCHEME
(SIWES)
SUBMITTED TO THE UNIVERSITY OF LAGOS

S ees

IN
PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE
OF BACHELOR OF SCIENCE
IN
PETROLEUM AND GAS ENGINEERING
IN THE

DEPARTMENT OF CHEMICAL AND PETROLEUM

ENGINEERING,
FACULTY OF ENGINEERING

BY

OFUM, BLESSING B.
170409014

AT

NIGERIAN NATIONAL PETROLEUM COMPANY LIMITED

NNPC Towers, Herbert Macaulay Way, Central Business District, Garki, Abuja, Nigeria

From January 16th, 2023 to June 30, 2023.

 CERTIFICATION.
I, OFUM, BLESSING BANJUALE a student of the Department of Chemical and Petroleum
Engineering, University of Lagos, Akoka with Matriculation number 170409014, hereby certify
that this Industrial training report was compiled by me in accordance to the requirements of the
Students’ Industrial Work Experience Scheme (SIWES) as a summary of my experience during
the period of my training (Jan, 2023 – July, 2023) at Nigerian National Petroleum Company
Limited (NNPCL).

OFUM, BLESSING BANJUALE DATE

DATE
(Institution-based supervisor)

STANLEY CHUKS DATE

(Industry-based supervisor)

DEDICATION.
This project is dedicated to everyone out there contributing to the growth and development of
Nigerian students. I will also like to dedicate this report to my parents, my sister and everyone
who contributed to the success of my SIWES training.

ACKNOWLEDGEMENT.
My sincere gratitude goes to Almighty God for His grace, protection, strength and for seeing me
through my internship with NNPC Limited.

My appreciation goes to my parents, Mr. and Mrs. Ofum for their guidance and support morally
and financially throughout this training period.

I will like to acknowledge the management of the University of Lagos with special regards to the
Faculty of Engineering and department of Chemical and Petroleum Engineering and also my
departmental SIWES coordinator, Dr. Owolabi for the necessary support throughout my SIWES
process.

To my industry-based supervisors, Mr. Stanley Chuks and Mr. Emmanuel Luke and my
institution-based supervisor, …. for all their support and encouragement and for imparting me
positively during the training period, I will like to say thank you.

I also acknowledge with utmost pleasure the following people who helped directly and indirectly
during my internship with NNPC Limited: Engr. Jude Ejere, Engr. Raphael Chindah, Engr.
Jideofor Etele, Mr. Ogidikpe Ayauge, Mr. Peter Ogolo and all other members of the Gas
Department.

Finally, I will like acknowledge my fellow interns at the National Engineering and Technical
Company, NNPC Limited: Asiya Tirmidhi, Adeniji Emmanuel, Shettima Jibril, Abba Abubakar,
Lukman Aminu, Isa Hambali, Youssouf Illiasso, Emmanuel Omemu, Owen Diche, Gabriel Udu
and Stella Enyie whose co-operation and support were key to the successful completion of the
assigned projects.

ABSTRACT.
 The Students Industrial Work Experience Scheme (SIWES) was established in response
to the need to bridge the gap between the theoretical aspects of the respective disciplines and real
practical applications of the principle involved. The aim of the program is to expose students to
the industry, to gain the required knowledge on how an industry operates and broaden their scope
of understanding on what has been taught in the class

This report entails the overview of my experience and observations during the course of
my 6 months industrial training with Nigerian National Petroleum Company Limited (NNPCL).
The purpose of this report is to highlight experiences gained through tasks performed, difficulties
encountered and recommendations. A brief summary was made about the organization, its
history, organizational chart and nature of work done by the company.

I was opportune to work with the National Engineering Technical Company (NETCO), a
subsidiary of NNPCL, in the Capital Project Management division under the Refineries and
Turn- around maintenance unit where I gained a vast understanding of the steps involved in the
production of crude oil and separation and treatment of crude oil components and natural gas. I
also gained knowledge about refinery processes

Finally, it can be ascertained that the SIWES program was a huge success as it has
amplified my understanding of basic Petroleum Engineering principles, and the experience
garnered during the period has equipped me with critical skills that has made me a better aspiring
Engineer.

TABLE OF CONTENTS.
TITLE PAGE ……………….……………………….…………….……………………. i

CERTIFICATION………………….………………………………………………….... ii

DEDICATION ………………………………………………………………................. iii

ACKNOWLEDGEMENT ………….…………….……………………….…………… iv

ABSTRACT ………………………………….……………………….……................... v

TABLE OF CONTENTS …………………….………………………………………… vi

LIST OF TABLES …………………….…………………………………….................. vii

LIST OF FIGURES ……………….……………………….…………………………… viii

CHAPTER ONE: STUDENTS INDUSTRIAL WORK EXPERIENCE SCHEME

1.1 INTRODUCTION TO SIWES ……………………….………………………....1

1.2 ORGANIZATION AND OPERATION OF SIWES ……………………............ 3

1.3 AIMS AND OBJECTIVES OF SIWES ……………………………….…............4

CHAPTER TWO: COMPANY PROFILE

2.1 NNPC LIMITED AT A GLANCE ……………………….……….……………. 5

2.2 BUSINESS DIVISIONS IN NNPCL ……….……………................................... 7

2.3 NNPC LIMITED ORGANOGRAM ...............................….………….……........ 8

2.4 DEPARTMENT OF ATTACHMENT ....……….……….…………….……....... 9

2.5 NETCO ORGANOGRAM AND RESPONSIBILITIES ….………………….... 10

CHAPTER THREE: THE TRAINING PROGRAMME

3.1 UPSTREAM OIL AND GAS INDUSTRY
3.1.1 ORIGIN OF CRUDE OIL AND GAS ………….……….…………...…
3.1.2 EXPLORATION OF CRUDE OIL ………………………………………
3.1.3 PETROLEUM ENGINEERING....................................................................
3.1.4 DRILLING ENGINEERING ……………….…………………………….
3.1.5 RESERVOIR ENGINEERING ………………………………………….
3.1.6 PRODUCTION ENGINEERING …………………………………………

3.2 INTRODUCTION TO NNPC LIMITED REFINERIES

3.2.1 TYPES OF REFINERIES .............................................................................
3.2.2 EQUIPMENT USED IN A REFINERY ..........................................................
3.2.3 THEORETICAL DISTILLATION UNIT ........................................................
3.2.4 WARRI REFINING AND PETROCHEMICAL COMPANY.........................
3.2.5 KADUNA REFINING AND PETROCHEMICAL COMPANY ....................
3.2.6 PORTHARCOURT REFINERY (PHRC) ..........................................................

3.3 REFINERY PROCESSES…………………………………........................................

3.3.1 ATMOSPHERIC CRUDE DISTILLATION UNIT (CDU)……....................
3.3.2 VACCUM DISTILLATION UNIT (VDU)…………………………………...
3.3.3 NAPHTHA HYDROTREATING UNIT (NHU)……..........................................
3.3.4 CATALYTIC REFORMING UNIT (CRU)…………………………………
3.3.5 KERO HYDRO-TREATING UNIT (KHU)……………………………………
3.3.6 FLUID CATALYTIC CRACKING UNIT (FCCU)……………………………

3.5 REFINERY TURNAROUND MAINTENANCE ..............................................................

CHATER FOUR: INTERNSHIP EXPERIENCE

4.1 OVERVIEW OF INTERNSHIP EXPERIENCE ………………………...….……...
4.2 KNOWLEDGE GAINED …………………………………………………...…….…
4.2.1 SKILLS LEARNED
4.2.2 COURSES AND TRAININGS ……………………………………….…........
4.3 HEALTH, SAFETY AND ENVIRONMENT (HSE) TRAINING..............................
4.3 TASKS ACCOMPLISHED …………………………………….………….……...
4.4 RELEVANCE OF TRAINING TO COURSE OF STUDY …………….……………
4.5 CHALLENGES FACED DURING INTERNSHIP …………….……….……………

CHAPTER FIVE
5.1 CONCLUSION …………….……….………………...………………………………
5.2 RECOMMENDATIONS ….……….…………………………………………………
REFERENCES ….……….……………………………...…………………………………

CHAPTER ONE: STUDENTS INDUSTRIAL WORK

EXPERIENCE SCHEME.
1.1 INTRODUCTION TO SIWES.
For individuals pursuing a career in/any of science, engineering and technology disciplines
(SET), the need for hands-on practice/experience accompanying the theoretical knowledge
received in the lecture halls cannot be overemphasized. This can be seen in the reality that an
educated person should not only be knowledgeable, but must also be able to apply his/her
theoretical knowledge to make positive contributions to the growing economy, by performing
his/her jobs/work effectively.

These indicate that theoretical knowledge together with practical skills and orientation is very
important in order to make university/polytechnic students productive. Hence, Students’
Industrial Work Experience Scheme (SIWES), a component of the Cooperate Education system,
was put in place to equip students with contributions from industry to add to knowledge gained
from institutions of learning and thus, bridge the gap between the learning acquired by graduates
in Nigeria, and the skill set required in the world of work.

HISTORY OF SIWES.
Students who had some form of industrial training, were only those who participate industrial
jobs/work during the holiday. This led to disapprovals of science, engineering and technology
(SET) graduates from experts, on the basis that, the Nigerian graduates lack the relevant practical
skills required in the workplace. However, some higher institutions introduced Student Work-
Experience Programme (SWEP). It was designed to provide students with practical knowledge
of their respective courses, and was conducted during the long vacation in the institutional
workshops, under simulated industrial conditions for second year students in universities who
have been introduced to their engineering and technology courses. Students were given the
opportunity to interact with the tools and machines available in the workshops, in the production
of simple jobs, as well as, being introduced to some simple practices which they are likely to
encounter in the industry.

On identification of this fault in meeting with the required standard in the formation of SET
graduates, especially as regards having relevant production skills, the Industrial Training Fund
established in 1971 by Decree 47, initiated the Students’ Industrial Work-Experience Scheme
(SIWES) in 1973. The scheme was conceived to introduce students to the industrial environment
and hence, develop the occupational competences of the students required for national and
economic development.

In 1974 SIWES started with 748 students from 11 institutions. By 1978, the scope of
engagement in the scheme increased to 5000 students from 32 institutions. However, the
Industrial Training Fund (ITF) withdrew from management of SIWES in 1979 as a result of
problems of organizational logistics and increased financial burden. The Federal Government,
however, funded the scheme through the National Universities Commission (NUC) and the
National Board for Technical Education (NBTE) who managed SIWES for five years (1979-
1984), this was done in conjunction with their respective institutions. In 1985, the Federal
Government put forth Decree No 16, which required “all students enrolled in specialized
engineering, technical, business, applied sciences and applied arts should have supervised
industrial attachment as part of their studies”.

The ITF was directed by the Federal Government to take charge and resume responsibility for
SIWES management, together with the supervising agencies (1984/1985). As years went by, the
number of institutions taking part in SIWES increased and the students participating varied. In
the same vein, the funding of SIWES also experienced incremental changes. Presently,
participation in the scheme is limited to only science, engineering and technology programs in
Universities and Polytechnics while in Colleges of Education Technical Education, Agriculture,
Business, Creative Arts & Design, computer studies and Home economics programs are eligible.

1.2 ORGANIZATION AND OPERATION OF SIWES.

 The Federal Government, the Industrial Training Fund (ITF), the Supervising Agency,
National Universities Commission (NUC), employers of labor and Institutions (universities and
polytechnics) all have specific roles to play in the management of SIWES. These roles are:

1. The Federal Government.

• To provide adequate funds to the ITF through the Federal Ministry of Industry for the
scheme
• To make it mandatory for all ministries, companies and parastatals to offer places to
students in accordance with the provisions of Decree No. 47 of 1971 as amended in 1990
• Formulate policies to guide the running of the scheme nationally.

2. The Industrial Training Fund (ITF).

• Implement policies and design guidelines on SIWES
• Prepare materials on the Students Industrial Work Experience Scheme (SIWES) as well
as operational guidelines for consideration of Management
• Collaborate with supervisory Agencies (NUC, NBTE and NCCE) as well as other
SIWES Stakeholders such as Federal Ministry of Education, Federal Ministry of Trade
and Investment, Employers of Labor and Institutions on SIWES matters
• Coordinate and prepare comprehensive Annual returns on SIWES
• Organize Conferences, Workshops, Seminars and Meetings on SIWES matters.

3. The Supervisory Agencies (NUC, NBTE, NCCE etc.)

• To ensure the establishment and accreditation of SIWES unit/Directorate in institutions
under their jurisdiction
• To vet and approve Master and Placement lists of students from participating institution
and forward to ITF
• Fund SIWES Directorate adequately in participating institutions
• To direct for the appointment of full-time SIWES Coordinator/Director
• Review programs qualified from SIWES regularly.
1.3 AIMS AND OBJECTIVES OF SIWES.
 Provides an avenue for students in institutions of higher learning to acquire industrial
skills and experience in their approved course of study.
 There is an opportunity for students to improve their soft-skills such as confidence,
interpersonal skill, strategic thinking, time management, analytical skills etc.
 Enhancing students’ contacts with potential employers while on training.
 To help students appreciate the role their professions play in the society.
 To make the transition of students from university life to graduation to the working
environment easier and facilitate students’ contact for later job placements.
 To expose students to the latest developments and technological innovations their chosen
professions.
 Enabling students appreciate the connection between their courses of study and other
related disciplines in the production of goods and services.
 To open an incoming generating channels for students, such that they collect stipends
while undertaking this process and still have affiliation to the firm after the scheme.
 To expose students to work methods and techniques in handling equipment and
machinery that may not be in educational institutions.

CHAPTER TWO: COMPANY PROFILE

2.1 NNPC LIMITED AT A GLANCE
NNPC Limited is a for profit oil company in Nigeria. Formerly a government-owned
corporation, it was transformed from a corporation to a limited liability company in July 2022.
NNPC Limited is the only entity licensed to operate in the country's petroleum industry. It
partners with foreign oil companies to exploit Nigeria's fossil fuel resources.

NNPC was established on 1 April 1977 as a merger of the Nigerian National Oil Corporation and
the Federal Ministry of Petroleum and Energy Resources. NNPC by law manages the joint
venture between the Nigerian federal government and a number of foreign multinational
corporations, which include Shell, Agip, ExxonMobil, TotalEnergies and Chevron. Through
collaboration with these companies, the Nigerian government conducts petroleum exploration
and production.

The NNPC Towers in Abuja is the headquarters of NNPC. Consisting of four identical towers,
the complex is located on Herbert Macaulay Way, Central Business District Abuja. NNPC also
has zonal offices in Lagos, Kaduna, Port Harcourt and Warri. It has an international office
located in London, United Kingdom.

Following passage of a Petroleum Industry Act in August 2021, NNPC now operates as a
commercial entity without relying on government funding and direct controls. NNPC was
established as a limited liability corporation in the hopes that a private entity will find it easier to
access international capital markets.

NNPC has sole responsibility for upstream and downstream developments. In 1988, the

corporation was commercialized into 11 strategic business units, covering the entire spectrum of
oil industry operations: exploration and production, gas development, refining, distribution,
petrochemicals, engineering and commercial investments.

According to the Nigerian constitution, all minerals, gas, and oil the country possesses are
legally the property of the Nigerian Federal Government. The revenue gained by the NNPC
accounts for 76% of federal government revenue and 40% of the entire country's GDP. As of
2000, oil and gas exports account for 98% of Nigerian export earnings.
NNPC Limited is now taking the lead with a clear focus on sustainability. Firstly, by determining
its emission baseline through the development of Environment, Social and Governance (ESG)
framework, as well as the conduct of its company-wide Greenhouse Gases inventory. In this
rapidly changing environment NNPC has committed themselves to operating in a sustainable
manner as a responsible business entity ensuring that activities continue to be carried out in line
with the principles of economic, social and environmental development. The energy transition
plan is designed to ensure a low carbon footprint across its businesses through New Energy using
various means such as renewables, carbon neutral fuels and gases, and Energy efficiency.

NNPC Limited Value Statements.

Vision: To be the dynamic global energy company of choice.

Mission: Reliably delivering energy while continuously creating value for all stakeholders.

Values: Integrity, Excellence and Sustainability.

Strategy: NNPC strategy is focused on growing their global energy delivery capacity.
2.2 BUSINESS DIVISIONS IN NNPC LIMITED.

The NNPC’s business operations are managed through Strategic Business and Corporate
Services Units (SBUs/CSUs) in diverse locations across Nigeria. The NNPC Limited Group
comprises the NNPC Board, the group managing director’s office, five directorates as listed
below. Each of the directorate is headed by an Executive Vice President (EVP). Its divisions are
headed by Chiefs, while its subsidiary companies are headed by Managing Directors.

Directorates:

 Upstream
 Downstream
 Gas, Power and New Energy
 Finance
 Business Services

Upstream: To ensure maximum economic performance of upstream activities through

development of oil and gas reserves to achieve production targets in a safe and sustainable
manner.

Gas & Power: To unlock stranded gas and increase commercial gas volumes by expanding
investments in gas processing and transmission network and access untapped markets to service
existing and new gas-based industries, power, and LNG projects.

New Energy: To provide sustainable low carbon energy solutions for end users through
investment, commercial production, supply of carbon neutral fuels, renewable energy such as
solar; Renewable power, Biofuels-Fuel Ethanol, Biodiesel, Biogas, wind etc., while engaging in
Greenhouse Gases (GHG) emission reduction projects and services.

Downstream: To ensure maximum economic performance and energy supply stability for
domestic market through customer focused and sustainable business operations.

Non-Energy: To create deliver and capture value from viable non-core energy business
ventures.

2.3 NNPC LIMITED ORGANOGRAM.

NNPC BOARD
 GROUP MANAGING
DIRECTOR NNPC

GOVERNANCE, RISK &

LEGAL ADVISER
COMPLIANCE
SMALL BUSINESS
CORPORATE PLANNING
ADMINISTRATION
&STRATEGY

GAS, POWER & BUSINESS

UPSTREAM DOWNSTREAM FINANCE
NEW ENERGY SERVICES

NNPC E&P NNPC Gas NNPC Trading Corporate

Limited Infrastructure Limited (NTL) Finance Comunication
(NEPL) Company
(NGIC) Health, Safety
NNPC NNPC Retail Finance and &Environment
Upstream NNPC Gas Limited (NRL) Investor
Investment Marketing Relations Human Capital
NNPC
Management Limited Management
Shipping
Services (NGML) Financial Information
Limited (NSL)
(NUIMS) Control Technology
NNPC Gas &
NNPC Division (ITD)
NNPC Energy Power NNPC
RefChem
Services Investment Pension Research,
Limited
Limited Services Limited Tech &
(NRCL)
(EnServ) (NGPIS) Innovation
NNPC NNPC Non- NNPC
Downstream Energy Foundation
NNPC
Investment Investment
Engineering Security
Services Services
and Technical
(NDIS) (NNIS)
Company Supply Chain
(NETCO) Nigerian Management
Pipelines & Tax
Storage NNPC
Company Academy
Limited (NPSC)
Treasury NNPC
Figure #. NNPC Limited Organogram. National Properties
Energy Limited
2.4 DEPARTMENT OF ATTACHMENT. Reserve
Management NNPC Medical
Company Services
(NERMC)
During my SIWES I worked with NNPC Engineering and Technical Company (NETCO).
NETCO is the engineering subsidiary of NNPC established in 1989 to acquire engineering
technology through direct involvement of the parent corporation in all aspects of Engineering in
the Oil and Gas and non-oil sectors of the economy.

NETCO’s vision was outlined to become Nigeria’s premier indigenous Engineering Company
with the strategic vision of providing Basic/Detailed Engineering, Procurement, construction
Supervision and Project Management capability, using state-of-the-art technology. From concept
studies to detailed Engineering, NETCO offers the complete range of Engineering disciplines
required for robust, innovative and cost efficient Greenfield development and
modification/requalification of ageing offshore assets required to produce beyond original design
life.

Until 1997 it was a JV between Nigerian National Petroleum Corporation (NNPC) and American
corporation Bechtel, Inc. NNPC purchased Bechtel’s shares thereby making NETCO a wholly-
owned subsidiary. NETCO provides design and Engineering services across the life cycle of oil
and gas assets. Since the exit of Bechtel, NETCO has executed many significant projects and
was awarded the prestigious ISO 9001 Quality Certificate in May 2000 by Bureau Veritas
Quality International (BVQI). NETCO in strategic alliances with qualified and tested companies,
is presently venturing successfully into the EPCI (Engineering, Procurement, Construction and
Installation).

Key Activities of NNPC Engineering and Technical Company (NETCO).

 Carry out Engineering, Procurement, Construction, Installation, Commissioning,

Operations and Maintenance (EPCICO&M)
 Carry out conceptual and feasibility studies for engineering projects
 Provide Basic, Front-End Engineering Design (FEED) & Detailed Engineering Design
 Provide effective Project Management Services
 Provide Quality Assurance & Quality Control of engineering systems including
processing, production and manufacturing plants
  Conduct Health Safety and Environment (HSE) Management/Studies
 Carry out Project cost estimating, benchmarking and monitoring
 Offer technical capacity development as a service
 Carry out decommissioning and abandonment services – leveraging 3rd party partnerships
 Manage construction supervision (i.e., oversight of construction activities)

Key Partners

 NNPC Ltd subsidiaries – Upstream, Midstream and Downstream entities

 IOCs, Indigenous Oil Companies, Marginal Operators
 Other upstream, midstream and downstream players
 Energy service providers
 OEMs and Suppliers
 IT companies
 Strategic business partners/sub-contractors
 Regulators – such as NCDMB, NUPRC, NMDPRA

Value Proposition

 Competitive Pricing
 Timely and quality service delivery
 Strategic emphasis on sustainable deployment of key activities

Key Resources

 Qualified staff: engineers, technicians, managers – and adjusted manpower structure (vs
competitors)
 Strong IT team to digitalize processes
 Technical knowledge & know-how
 Technologies & systems

2.5 NETCO ORGANOGRAM AND RESPONSIBILITIES

MD, NETCO
Legal/General
Counsel
GRC
Security
 Figure #. NNPC Engineering and Technical Company (NETCO) Organogram.

NETCO Divisions Accountability.

 Chief Operating Officer (COO): Oversees the holistic operational value chain, from EPC
to Commissioning and Installation, to Operations and Maintenance for projects contracted to
NETCO

 Project Management Office (PMO): Oversee E2E PMO and controls of projects across the
portfolio from kick-off to delivery

 Commercial & Business Development: Oversees customer contracts and strategic

initiatives to identify potential leads and build customer relationships, as well as holistic BU
strategy and sustainability efforts

 Finance: Directs and manages finance and accounting operations

 Business Services: Ensures coverage for critical functions such as SCM and HSE

 Governance, Risk & Compliance (GRC): Prevent incidence due to noncompliance of best
practices and regulation

 Legal/General Counsel: Ensure regulatory compliance and mitigate potential exposure

 CHAPTER THREE: UPSTREAM OIL AND GAS INDUSTRY
Upstream industry is the portion of the oil and natural gas industry that is responsible for
finding crude oil and natural gas deposits, along with producing them. Upstream industry is
sometimes known as the exploration and production or E&P sector. This part of
the petroleum industry includes all activities that happen out in the field including drilling wells,
trucking supplies, and mining oil sands. In addition, it includes planning and preparation -
including environmental studies and engineering plans.

Figure #. Representation of upstream, midstream, and downstream industry.

3.1.1 ORIGIN OF OIL AND GAS

Many theories exist about how oil and gas were formed. The most popular (and perhaps the best)
is the organic theory. The organic theory holds that oil and gas came from the remains of plants
and animals. These organisms were very small, even microscopic in size, and they lived in rivers
and seas that must have existed in Earth’s distant past, millions and millions of years ago. These
plants and animals were carried down to the sea (which was also full of these organisms), along
with river silts and mud. As they died, they fell to the ocean floor where they mixed with the silt,
sand and mus. This led to the formation of a rich, organic mixture that was cut off from any
oxygen dissolved in the water. With no oxygen, the organic material could not decay normally.
As time went by, for thousands of years, the mixture of silt, sand, mud and organic matter
continued to build up. High heat, pressure, pressure, bacteria and chemical reactions began to
work on the organic substances locked in the lowest layer. The end result was that the organic
remains were transformed into oil and gas. This oil and gas was present in the pore spaces of the
rock. Also, earthquakes moved blocks of earth upward, downward, and sideways. Erosion from
wind, water and ice wore away the land. These events caused the newly-formed petroleum to
move out of their birthplace. The petroleum flowed through the rock moving from pore to pore
in a tortuous path. Sometimes, it reached the surface and sometimes, its upward motion was
blocked by an impermeable rock layer deep below the surface. This trapped oil and gas is what is
drilled today.

3.1.2 EXPLORATION OF CRUDE OIL

Crude oil can be found hundreds, or even thousands of feet below the ground or below sea level.
Thus, it is impossible to know exactly where a hydrocarbon trap is simply by looking.
Exploration geologists and geophysicists have the job of finding subsurface petroleum traps (an
arrangement of rock layers that contain an accumulation of hydrocarbons sealed by the
overlaying caprock) that could contain hydrocarbons. They do this using a science called
seismology. Seismology is the study of vibrations in the earth. These vibrations take the form of
sound waves which are studied on the surface of the earth. Man-made sounds can help
geophysicists to find petroleum traps. Seismology works on a principle similar to the echoes we
hear when the sound of our voices bounces back from a cliff or wall. In oil exploration, the
process is more technical as the traps are buried below the surface and the man-made sounds
must be able to go through not just air but thousands of feet of rock all the way down and back
up to the surface. In order to achieve this, an explosive such as a dynamite is used to make the
sound on the surface. Other times, a heavy steel plate dropped flat on the surface of a specially-
designed ruck can also be used. Offshore, where explosives 17 can harm marine life, air guns are
frequently used. These trail behind the boat and make lowfrequency popping noises. The
reflections of the sound, or echoes are picked up with the use of several sensitive detectors called
geophones in land exploration and hydrophones in offshore exploration. The geophones convert
the sound vibrations to electric current, which is sent along a cable to a tape recorder which
records the echoes. In a laboratory, the tapes are played back into computers, and record, or
seismic sections are made.

Expert interpretations of these sections reveal what may be a petroleum trap. For example, a
bright spot on a seismic section shows an echo which is much stronger or weaker than usual, and
may indicate the presence of natural gas in a trap. It is safe to say, however, that the only sure
way to find out whether hydrocarbons are in a trap is to drill a hole down into it.

3.1.3 PETROLEUM ENGINEERING

The science of Petroleum Engineering can be roughly divided into three categories:

➢ Drilling Engineering involves the creation of wellbores that penetrate from the surface of the
earth to underground deposits of hydrocarbons.

➢ Reservoir Engineering involves the analysis of fluid quantity, fluid movement, and recovery
operations that take place within a reservoir as well as the management of development and
depletion practices aimed at achieving optimum profitability.

➢ Production Engineering involves the subsurface completion and operation of wells, and the
installation and operation of surface production facilities required to deliver gas and liquid
hydrocarbons with specified (by the producer and the buyer) fluid properties, or to separate and
properly dispose of the byproducts

3.1.4 DRILLING ENGINEERING

Drilling creates the wellbores that penetrate from the surface of the earth to potential
underground deposits of hydrocarbons. The earth is penetrated in steps, and at each step the
borehole is cased with steel pipe and cement is used to seal the pipe to the surrounding rock. To
drill a hole or well requires a drilling rig. Exploration wells use conventional rotary drilling, used
in the shallow portion of the borehole. However, before drilling starts, a round length of hollow
pipe is driven or hammered into the ground. This pipe is called the conductor casing and it keeps
the ground from caving in during drilling. Rotary drilling uses pipe weight on a bit is pressed
hard against the ground and turned. The bit is screwed into the end of a hollow pipe called a drill
pipe. This drill pipe is carefully guided into the opening in the top of the casing. A device known
as the rotary table turns or rotates the 19 pipe and bit connected to it. The rotating bit punches
into the rock and scrapes and gouges it out to make a hole. Drilling continues past the conductor
casing and into the raw earth below. At the same time, a viscous liquid called drilling fluid, or
drilling mud is pumped down the hollow drill pipe (stem), and goes out of the drill bit nozzles,
and up the borehole-pipe annulus carrying fragments of rock (cuttings) that the bit has drilled. At
the surface, the cuttings are sifted out of the mud by the shale shaker. Most of the cuttings are
thrown away but the clean mud is pumped back down the drill pipe again. This process is
continuous and allows the bit to keep on drilling rock without the cuttings getting in the way.
Upon reaching a pre-planned depth, based on seismic data, information is gathered and the well
is evaluated for commercial quantities of hydrocarbon. This is done by cutting out a core sample
of the rock from the reservoir area seen on the seismic data. This core sample is then analyzed at
a laboratory to find out the parameters of the reservoir. They can also test the formation
(reservoir) by conducting a process called well logging, where they lower a special instrument
into the well. This instrument records the electrical, radioactive, or acoustic properties of the
formation and sends it to the surface in form of lines or curves which experts can then examine.

3.1.5 RESERVOIR ENGINEERING

Reservoir engineering involves using the laws of science to maximize the value of the zones
where oil and gas are “stored” for the benefit of mankind. It involves:

• Evaluation of reservoir development options; development and depletion plan: estimating in-
place hydrocarbon reserves and optimum production rates and so on

• Plan for production maintenance and enhancement: develop production maintenance programs
- drilling and workovers and monitor state of reservoir depletion and fluid distribution

After the geoscientists find the reservoir and the drilling engineers drill the first exploratory
wells, the next job is for the reservoir engineers. Their job is to find out the extent of the
hydrocarbons using seismic data, and data gotten from the core sample or well logging. Some of
the parameters that reservoir engineers use can be estimated using well logs, pressure tests or the
core sample. They include:
• Lithology: Type of rock

• Porosity: Measure of pore space in a rock

• Permeability: Measure of ease of fluid flow through the inter-connected pore space

• Wettability: Measure of tendency of wetting fluid to adhere to the surface of sand grains.

• Mechanical & Electrical Properties: Measure of rock strength and electrical factors utilized in
estimating water saturation.

As mentioned earlier, oil and gas are present in the pore spaces of the rock. When the bulk
volume of the area has been estimated from seismic data, in addition to some other parameters,
they can then calculate how much oil is present in the reservoir using the formulas below.
Assuming homogeneity of the reservoir, 𝑃𝑜𝑟𝑒 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑎 ℎ𝑦𝑑𝑟𝑜𝑐𝑎𝑟𝑏𝑜𝑛 𝑠𝑦𝑠𝑡𝑒𝑚 (𝑏𝑜𝑡ℎ 𝑜𝑖𝑙
𝑎𝑛𝑑 𝑔𝑎𝑠) = 𝐵𝑢𝑙𝑘 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑡ℎ𝑒 𝑟𝑜𝑐𝑘 ∗ 𝑃𝑜𝑟𝑜𝑠𝑖𝑡𝑦 Where 𝐵𝑢𝑙𝑘 𝑣𝑜𝑙𝑢𝑚𝑒 = 𝐶𝑟𝑜𝑠𝑠_𝑠𝑒𝑐𝑡𝑖𝑜𝑛𝑎𝑙
𝑎𝑟𝑒𝑎 ∗ 𝑡ℎ𝑖𝑐𝑘𝑛𝑒𝑠𝑠 In the pore spaces, there’s oil, gas and water. So, to find the actual amount of
hydrocarbons only (oil and gas), they use something called “saturation”. Then, 𝐻𝑦𝑑𝑟𝑜𝑐𝑎𝑟𝑏𝑜𝑛
𝑃𝑜𝑟𝑒 𝑉𝑜𝑙𝑢𝑚𝑒 (𝐻𝐶𝑃𝑉) = 𝑃𝑜𝑟𝑒 𝑣𝑜𝑙𝑢𝑚𝑒 ∗ 𝐻𝑦𝑑𝑟𝑜𝑐𝑎𝑟𝑏𝑜𝑛 𝑠𝑎𝑡𝑢𝑟𝑎𝑡𝑖𝑜𝑛. When this volume has
been gotten from the appraisal well, it is necessary to determine if it is economically feasible to
produce from that well. In order to do this, they determine the recovery factor of the reservoir.
Recovery factor can be determined from the:

➢ Density of the oil, which affects the hydrostatic pressure up the well

➢ Drive mechanism

➢ PVT data There are various reservoir drive mechanisms which include: solution-gas drive,
gas-cap drive, water drive, combination drive.

In cases where oil production is not optimal, some additional recovery steps can be done, in
addition to the natural reservoir drives. For example,

• Reservoir stimulation: The most popular techniques are: fracturing and acidizing. It’s necessary
in scenarios where petroleum and reservoir fluid are in the pore spaces, but the pore spaces are
not connected leading to low permeability. The purpose of the reservoir stimulation is to reduce
formation damage that may have occurred during drilling and overcome the problem of low
natural permeability.

• Gas lift: This method consists of injecting natural gas into a well in order to make it produce.
It’s frequently used on offshore platforms where space is limited. When the injected gas mixes
with the oil being produced, it makes the liquid column lighter. Thus, making it easier for the
pressure in the reservoir to push it up to the surface.

3.1.6 PRODUCTION ENGINEERING

After the geoscientists have discovered an oil reservoir, an exploratory well (with the conductor
casing) has been drilled, and the reservoir engineers have determined that the reservoir is
commercially viable, then, the next step is to complete the well so it can be produced. The steps
involved in transforming a drilled well to a producing one include;

• Casing

• Cementing

• Gravel Pack

Casing and Cementing

Casing is steel pipe the crew puts into the wellbore to prevent it closing in on itself and helps to
seal off the formation. It also protects the well stream from coming in contact with materials like
water or sand. The casing “strings” involve steel pipes joined together to make a continuous
hollow tube. There are 4 different casing strings put in the wellbore. Usually, two or more are
used as the crew drills deeper into the wellbore. The size of the hole and the diameter of the
casings reduce with increasing depth.

➢ Conductor casing: This is the first casing string put into the wellbore during drilling. Its
primary function is to prevent cave-ins because the ground close to the surface is soft and
disintegrates easily. It is hammered into place if the ground is soft enough. If not, it is cemented.
Cementing a casing involves pumping cement slurry into the wellbore to displace the existing
drilling fluids and fill the space between the casing and the actual sides of the drilled well. When
it hardens, it helps to permanently seal that casing string in place.

➢ Surface casing: This casing string protects fresh water zones which are close to the surface
and can get contaminated easily. It is cemented into place up to the surface

➢ Intermediate casing: This casing string is used in areas where there may be “troublesome
zones” e.g. abnormally pressured zones. It’s often the longest section of casing and in some
instances, more than one set of intermediate casings may be used.

➢ Production casing: This is the final casing string which penetrates the producing zone and is
used to protect and seal it. The production casing protects the tubing (through which the oil
actually flows) and other attachments on the tubing string.

Types of Completions

Different wells are completed in differently based on the nature of the reservoir, environmental
factors, equipment available, on shore/ offshore and so on. Some of these completions include:

➢ Open-Hole Completions: In a few instances, the production casing is not cemented through
the producing zone. Instead, it is set and cemented above the reservoir. The zone itself is left
open to the uncased hole drilled into it. Reservoir fluids simply flow into the open hole and
through the tubing. These completions are very rare because the formation must be composed of
hard, homogeneous rock that won’t break apart. This is because sand, stones and other materials
will degrade the tubing when they pass through it

➢ Perforated Liner Completions: A liner is a shortened length of casing that’s hung inside and
near the bottom of the intermediate or surface casing. It is cemented through the producing zone
and perforated by using a special kind of gun which provides openings for the hydrocarbons and
other fluids.

➢ Wire-Wrapped Screen Completions: This involves a specially shaped wire wrapped around a
short pipe (the screen) which is attached to the tubing string, and lowered into a well that has
been perforated. Usually, wire-wrapped screens are run with a gravel pack to filter out the sand
in a loose formation and allow only fluids to flow in the well.

Tubing Components
The tubing is the last string of pipe which is run-in after the production casing. It is the flow
string through which the well fluids flow. Often, a device called a packer is placed in the tubing
string. It seals off the annulus between the tubing and production casing at a point just above the
producing zone thus, forcing the formation fluids to flow into the tubing alone. Another device
frequently installed in the tubing string is the subsurface safety valve (SCSSV). As long as fluid
flow in the tubing is normal, the valve stays open and fluids continue to flow. However, if
something goes wrong, the safety valve senses the loss of control and closes. The closed valve
prevents the further escape of fluids. For this reason, the SCSSV is the most important
component of the tubing. It’s tested every 6 months to ensure it’s working properly. The
acceptable SCSSV leak rate is 900 scf/ hr and the engineers are notified if this rate is exceeded.
Wellheads and Pipelines
The wellhead is the equipment used to confine and control the flow of fluids from the well. It is
the surface equipment visible at a well location. It supports and seals the casing and tubing and
provides openings for flow as well as access to the wellbore. A typical wellhead is made up of a
casing head, tubing head, and Christmas tree. The Christmas tree is a group of valves and fittings
that controls the flow of fluids. These valves (wing valve, crown/swab valve, upper master valve
and lower master valve) are regularly tested with pressure gauges on it to ensure that they do not
leak beyond the acceptable limit. Another important device in the Christmas tree is the choke. It
is a restriction in the line through which well fluids exit the tree. It is used to control flow rate
with a small diameter constriction and is attached to the wellhead. Just downstream of the choke
is the well’s flow line. A production manifold is the assembly of piping and valves used to
commingle different wells’ fluids into a pipe header feeding a separator. Flow from a gas lift
compressor or pipeline, or from a water injection pump or supply line, can be distributed to
different wells from an injection manifold. Produced fluid is a multiphase mixture of gas and
liquid (oil, condensate, or water) flowing up the tubing, through the pipeline, and to the gas-
liquid separation point. Phase behavior and physical properties of the fluids are required to
properly size both the lines and the process equipment.
What is a Refinery?

Crude oil in its raw state is of little or no value until we take it through the refining processes and
transform it into various usable products. An oil refinery is an industrial installation where crude
oil is converted into useful products. In other words, it is an industrial site consisting of several
buildings and machinery for manufacturing petroleum products such as petrol, diesel, kerosene
and the likes.

Although each refinery has its own unique features, it is usually a massive structure with
different components including the processing units such as the boiler as well as the distillation
unit, storage facilities where refiners store crude oil and refined petroleum products. Running a
refinery does not only require employing several number of people to monitor different units in
the plant but also, enough manpower to cope with its continuous operations.

Petroleum refining is a process by which crude oil is separated into several fractions using
distillation and other chemical processes. The crude oil produced from underground reservoirs, is
a complex mixture of hydrocarbons of varying molecular weights and is of limited use to
industries in its raw state. However, when refined or separated into several components, the
crude oil produces a wide variety of hydrocarbon materials essential to our daily and modern day
requirement. The basic process that cuts across all refineries is that of crude distillation. This is a
physical process that separates the crude into primary products, some of which may have to
undergo further processing in conversion units to upgrade their quality to target specifications.
These conversion units ensure maximization of the products yield and quality improvement. The
number or types of these units differ from refinery to another. All refineries are therefore not the
same in terms of complexity and the number of installed facilities.
 3.2.1 TYPES OF REFINERIES

Topping Refineries

Topping refinery in not complex in nature but a processing plant with simple configuration.  A
refining plant with no processing units (to reduce sulfur levels, or other chemical reactions)

Hydro-skimming Refineries

Hydro-skimming refineries consists of hydro treating and reforming units to basic configuration
that makes up a topping refinery.

Produces high octane gasoline and Hydrogen

Conversion Refineries

Also known as cracking refineries, conversion refineries are refining plants that have all basic
units that make up both topping and hydro-skimming refineries as well as gas oil conversion
units. It includes reduction in production of residual fuels. In other words, conversion oil refining
plant produces lighter fuels such as gasoline, jet fuel and diesel. It worth mentioning that light
products are more profitable and environment friendly.

Deep Conversion Refineries

Deep conversion refineries comprise of the all units in conversion refineries with an additional
unit known as the coking unit. This unit allows treating and conversion of the heaviest crude oil
fraction also known as residual fuels into lighter products.

Other type of refinery includes: Greenfield refinery and Brownfield refinery

3.2.2 EQUIPMENT USED IN A REFINERY

The equipment in the refinery are divided into static and rotary equipment. Examples of static equipment
include; columns, valves, drums, condensers, ejectors, heat exchangers, desalters, strippers etc. while
examples of rotary equipment include; fin fans, pumps, turbines, compressors, generators etc.
USES OF EQUIPMENT
 Spray balls: are mainly used for cleaning tanks and vessels e.g. storage tanks etc.
 Stirrer: is used to agitate the liquid for speeding up the reaction or improving mixture.
 Fans: are widely used with air-cooled heat exchangers for process temperature control.
 Conveyor wheel: is commonly employed for loading and unloading trucks and moving
packages, pallets etc., through facilities or along assembly lines.
 Heat exchangers: are used to transfer heat from one medium to another. Also used for
cooling, condensing a very wide range of fluid.
 Kettle reboiler: is also a heat exchanger.
 Air coolers: are used for processing cooling and/or condensing.
 Fixed sheet heat exchanger: is used where even the slightest intermixing of fluid cannot be
tolerated.
 Plate exchangers: uses metal plates to transfer heat between two fluids.
 Double pipe heat exchanger: is used for sensible heating or cooling of process fluids in
application of small heat transfer.
 Boiler: is used in the production of steam.
 Vessels: are used to hold gas or liquid at a pressure above atmospheric pressure.
 Knock out drum: is used to remove any oil or water from the relived gases.
 Tray column: is used to carry out unit operations where it is necessary to transfer mass
between a liquid phase and gas phase.
 Packed column: is used to perform separation processes, such as absorption, stripping and
distillation.
 Open tank: is used to store petroleum products.
 Fixed roof tank: is used for products with vapor pressures less than 1.5psia.
 Sealed tank: is used to prevent gases from escaping into the environment.
 Storage sphere is used to store below ambient temperature liquids and pressurized gases.
 Centrifugal pump: is used to transport fluids by mechanical action.
o Ejector: is used to create a vacuum.
o Valve: is used to control the flow of liquid.
 Compressor: is used to supply high-pressure clear air to fill gas cylinders
3.2.2 THEORETICAL DISTILLATION UNIT

Types of Crude in Nigeria

• Bonny light
• Qua Ibae
• Escravo blend
• Forcados
• Pennington Anfani

Imported Crude Oil to Kaduna Refinery

• Venezuela Igomar crude oil
• Arabic light crude oil
• Kuwait crude oil

Major Refinery Products

• LPG
• PMS
• KEROSENE
• DIESEL
• LUBE OIL
• FUEL OIL
 • OTHER PETROCHEMICAL FEEDSTOCK
3.2.4 WARRI REFINING AND PETROCHEMICAL COMPANY (WRPC)

WRPC was incorporated as a limited liability company on the 3rd of November 1988 after the
merger of the then Warri Refinery and the Ekpan Petrochemical Plants.

The first Nigerian government wholly owned refinery was commissioned in 1978. It was built to
process 100,000 barrels of crude oil per day but was later de-bottlenecked to process 125,000
barrels per day in 1987. It was essentially built to add value to some of the refinery by-products
such as propylene rich stock and decant oil.

The operability of these plants is contingent on the availability and reliability of the following
facilities:

Electric Power and Utilities: These are produced within WRPC and are critical to the steady
processing of crude oil into petroleum and petrochemical products. They include among others:

 Steam
 Electricity
 Various types of water quality such as (firewater, process water, portable water, boiler
feed water and cooling water)
 Water treatment plants
 Nitrogen Plants
 Compressed air systems for instrument and plant air
 Effluent Water Treatment Plant

Figure #: Picture of a Part of WRPC

3.2.5 KADUNA REFINING AND PETROCHEMICAL COMPANY (KRPC)

KRPC was initially designed for capacity of 60,000 BPSD as a Hydro Skimming Plant
Due to the economics of scale, capacity for any refinery in Nigeria should not be below 100,000
BPSD.
The Refinery project was completed and the Fuels Plant was commissioned in 1980
However, this would have led to the production of large quantity of heavy ends. And one
practical and viable solution is reprocessing the heavy fuel oils. So that what initially was
planned to be simply a hydro skimming type refinery, developed into an integrated refinery.
The refinery would now be able to produce a wider variety of petroleum products, some of
which should be lubricating base oils. Hence, it became necessary to import suitable paraffinic
based crude oil from Venezuela, Kuwait or Saudi Arabia.
Products from the Refinery include; Fuels for use as Liquefied Petroleum Gas (LPG), Premium
Motor Spirit (PMS), Automotive Gas Oil (AGO) or Diesel oil, Kerosene, Fuel Oil, Sulphur and
those from the lubricating oils complex are Base Oils, Asphalt (Bitumen) and Waxes.

FINISHED PRODUCTS FROM THE REFINING & PETROCHEMICAL PLANTS

• PREMIUM MOTOR SPIRIT (PMS)
• KEROSENE (AVIATION AND DOMESTIC)
• LIQUEFIED PETROLEUM GAS (LPG)
• AUTOMOTIVE GAS OIL (AGO-DIESEL)
• LOW POUR FUEL OIL (LPFO)
• HIGH POUR FUEL OIL (HPFO)
• LUBE BASE OILS
• HYDRO-FINISHED WAX
• ASPHALT
 • LINEAR ALKYL BENZENE
• BENZENE
• HEAVY ALKYLATE
• KERO SOLVENT
• NORMAL PARAFFINS
• TOLUENE
• AROMATIC SOLVENT
• HEAVY PARAFFINS
• SULPHUR FLAKES

3.2.6 PORT HARCOURT REFINERY (PHRC)

PHRC Limited is made up of two refineries. The old refinery commissioned in 1965 with current
nameplate capacity of 60,000 barrels per stream day (bpsd) and the new refinery commissioned in 1989
with an installed capacity of 150,000 bpsd This brings the combined crude processing capacity of the Port
Harcourt Refinery to 210,000 bpsd.
The refinery used to be sufficient in power and utilities generated from the Power Plant & Utilities.
However, the refinery currently buys power from a private power plant situated in the refinery premises.
There are four (4) turbo-generators each with a capacity of 14MW of electricity per hour and four (4)
Boilers, capable of generating 120 tons of steam per hour each. The section also generates cooling/service
water, plant/instrument air and nitrogen.
PHRC produces the following products: - Liquefied Petroleum Gas (LPG), Premium Motor Spirit (PMS),
Kerosene (aviation and domestic), Automotive Gas Oil (AGO - diesel), Low Pour Fuel Oil (LPFO) and
High Pour Fuel Oil (HPFO).
PHRC boasts of newer process technologies that are not only state of the art but also not
available in the other NNPC refineries in Kaduna and Warri. These give us the ability to produce
lead free motor gasoline, a great step in Nigeria’s march toward joining the world in the clean air
efforts. For example:
1. The Catalytic Reforming Units of the Continuous Catalyst Regeneration (CCR) type
2. The Refinery has a Dimersol Unit
 3. It also incorporates a Butamer Unit
Like the other refineries, it has Fluid Catalytic Cracking and HF Alkylation Units
PHRC plants are grouped into sections; called an “AREA”.

PRINCIPAL FINISHED PRODUCTS

The products must attain certain specification before introduction into the market. These specifications
mark the quality of the refined products. For example, RON (Research Octane Number) is used for PMS,
SMOKE Point for DPK and Cetane Index for AGO, specialty products can also be produced, e.g.
unstenched LPG used in the vegetable oil extraction plants, ATK used in aviation, etc.

3.3 REFINERY PROCESSES

3.3.1 ATMOSPHERIC CRUDE DISTILLATION UNIT (CDU)
Raw crude oil is pumped to the unit after settling and dewatering at the tank farm. It passes through a heat
exchanger train, the desalter (for removal of salt and sediments), the pre-flash drum (for removal of lighter
ends), the main crude heater where it is heated up, when the main fractionator column. This is also called
the distillation tower in which the distillation trays ensure thorough mixing and separation of liquids from
vapors. The vapors are removed from the top of the fractionator, condensed and sent to the Saturated Gas
Concentration Unit (SGCU) for further separation and production of fuel gas; LPG/propane or cooking gas.

The liquids are withdrawn from the side of the fractionator, based on the boiling point ranges as products,
which includes:

• Whole Naphtha

• Straight Run Kerosene

• Gas oil (Light and Heavy Diesel Oil)

• Atmospheric Residue

These products are classified as either finished or semi-finished products. The semi-finished
products are further subjected to secondary processing to obtain finished products.

The whole naphtha is stabilized by stripping it further into lighter components (methane, ethane,
propane and butane), then split into Straight Run Gasoline (SRG) and Straight Run Naphtha
(SRN). The SRG is sent to intermediate product storage as one of the component to be blended
to produce Premium Motor Spirit (PMS).

The SRN is sent to Naphtha Hydro-treating and Catalytic Reforming Units (NHU/CRU) to
produce reformate used as component for PMS blending. The reformate is of a much higher
Octane Number (a critical measure of PMS quality) than Straight Run Naphtha.

The straight run kerosene, also known as Dual Purpose kerosene (DPK) is used either directly as
Household Kerosene or as Aviation Fuel after further processing and introduction of addictive.

The Lighter Diesel oil is finished product and used directly as Automotive Gas Oil (AGO) or
Diesel. The heavy Diesel Oil forms a part of the feedstock for the Fluid Catalytic Cracking Unit
(FCCU) and is sent to storage.

The last fraction is the Atmospheric Residue is sent to the Vacuum Distillation Unit to obtain
feedstock for FCCU.
3.3.2 VACCUM DISTILLATION UNIT (VDU)

The Atmospheric Residue is processed in this unit under low pressure. The products from this
unit are Light Vacuum Gas Oil (LVGO) and Heavy Vacuum Gas Oil (HGVO) and Vacuum
Residue.

The LVGO and HGVO are combined to form a composite product- Vacuum Gas Oil (VGO),
which is the feedstock for the FCCU. The bottom product of this unit, Vacuum Residue is sent to
storage for the blending of Fuel Oil.

3.3.3 NAPHTHA HYDROTREATING UNIT (NHU)

The purpose of this unit is to chemically treat the Straight Run Naphtha from the crude
distillation unit to remove compounds of lead, Sulphur, nitrogen, oxygen etc., little amounts of
which in the naphtha constitute poisons to the highly expensive catalyst of the Catalytic
Reforming Unit. The product of this unit is called Hydro-treated Naphtha which is the feedstock
for the Catalytic Reforming Unit

Hydro treating Reactions

1. Desulphurization
a. Mercaptanes:
 Using catalyst such as;
Cobalt molybdenum on Alumina, Co – Mo/ Alumina
Nickel molybdenum on Alumina, Ni – Mo/ Alumina

3.3.4 CATALYTIC REFORMING UNIT (CRU)

The purpose of the catalytic reforming unit is to upgrade the low octane straight run naphtha to
the high octant product, called reformate which is used as a blending component for PMS.
Excess hydrogen is also produced in the reaction and this is purified and stored for use at the
NHU, KHU, Butamer, etc. A small amount of off- gas is produced and sent to the refinery fuel
gas header. The catalyst used in this unit is Platinum Ranium Oxide on Alumina.

3.3.5 KERO HYDRO-TREATING UNIT (KHU)

This unit is principally to upgrade Straight Run Kerosene to specifications acceptable for
aviation use. The operation is similar to that the NHU in terms of removal of Sulphur, nitrogen
and oxygen, and improves the quality of the smoke and freezing points of the product.
The raw kerosene from the CDU is mixed with hydrogen and catalytically treated to produce
Aviation Turbine Kerosene (ATK).
3.3.6 FLUID CATALYTIC CRACKING UNIT (FCCU)
This is a very important unit in the refinery. The purpose of this unit is to catalytically convert
Heavy Diesel Oil from CDU and Vacuum Gas Oil from VDU into more valuable products such
as LPG, FCC Gasoline. Light Cycle oil and Decanted oil. The feedstock is heated in a series of
heat exchangers, then atomized by steam and injected into the Riser Reactor where catalytic
cracking reaction occurs. The reaction product and catalyst flow up to the cyclones in the Riser
Disengager where the hydrocarbons separate from the catalyst (zeolite, liquid).
The spent catalyst flows downwards the Riser to the Regenerator where the coke deposited on
the catalyst during the reaction is burnt off and re-circulated back to the Riser.
The Gas Concentration Unit (GCU) is an integral part of FCCU which processes gas streams
from the FCCU itself, Alkylation, Merox and Butamer Units to produce propane and butane.