CHAPTER ONE

1.0 INTRODUCTION
Students’ Industrial Work Experience Scheme (SIWES) is a human capital
formation programme through industrial attachment for which students are
expected to have a practical experience on the basis of theories and principles
acquired in the teaching-learning process. However, the prevalence of the
inability of participants of SIWES to secure employment after the programme
casts doubt on the continuing relevance of SIWES to the contemporary
industrial development drive in Nigeria.

This technical report is a succinct documentation of my exposure and

experience gained in the area of borehole drilling supervision during my
industrial work experience scheme (SIWES) with a company called Pee drilling
company Nigeria limited Awka, Anambra State. The programme started on 10th
January and ended in 12th May.

1.1 HISTORICAL DEVELOPMENT OF SIWES

The students industrial work experience scheme (SIWES) came into
establishment of the industrial training fund (ITF) under the degree No 47 of 8th
October, 1971, in a bid to boost indigenous capacity of the nation’s industrial
need, the fund in its policy statement No.1 published in 1973 inserted a clause
dealing with the issues of practical skills which states that “the seek will seek to
work out cooperative machinery with industry, where student in institution of
higher learning may acquire training in industry or mid- career attached by
contributing to the allowance payable to the student’’

The fund identified a great gap between theory and practice of Engineering and
technology of higher learning and has come to an effort to eliminate this gap.
The fund initiated work experience scheme (SIWES) in 1973.SIWES is a skill
training programme designed to expose and prepare students of universities,

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polytechnics and college of education to real life work situations including
environmental, technical and business students in higher institution of training
in Nigeria.

1.2 AIMS AND OBJECTIVE OF THE SIWES

 To provide students with industrial skills and needed experience while the
course of study.
 To create conditions and circumstances, which can be as close as possible
to the actual workflow.
 To give students the ability to try and apply the given knowledge
 To teach students the techniques and equipment that may not be available
within the walls of an educational institution.
 To provide student with an opportunity to applied their theoretical
knowledge in real work situation thereby bridging the gap between
theories and practical.
 To provide avenue for students for institutions in higher learning to
acquire industrial skills and experience in their course of study while in
school.
 To expose students to work methods and techniques in handling
equipment and machineries that may not be available in some educational
institutions.
 To enhance and strengthened employers involvement in the education
process and preparing student for employment in the industries.
The objectives of SIWES programme are all about strengthening future
employees. Such program is successful attempt to help students to understand
the underlying principles of their future work. After passing the programs, the
students can concentrate on the really necessary factors of his or her work

1.3 THE SCOPE OF THE SCHEME

The scope of this programme varies from one department to another. The
regular students in Agric and bio resources engineering department of Nnamdi
Azikiwe university observe this programme in 400level 2nd semester for a
period of six months. This is observed by all institution of higher learning
offering Agric Engineering and related disciplines.

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The scheme therefore is a pre-requisite to graduating students from institution
of higher learning most especially earth related courses like soil and water
engineering, mining, petroleum engineering, applied hydrology etc. Its scope
revolves around practical experience on site.

1.4 CONTRIBUTION OF THE SCHEME

The scheme is making a good impact in the economy and technological
development of the country especially on human resources development. The
summary of some of the contribution of the scheme are;

I. It has contributed to the improved quality of skilled man power in

Nigeria

II. It creates more relationship between institutions and industries

III. It offers students an opportunity to associate themselves with workers

at various levels in the industries.

IV. It assures the institutions that the quality of the student produced by
them are to standard after going through the SIWES programme as it
forms a part of the assessment of the award of certificate and degree.

V. It prepares the students so that they can fit into employments in the
industries.

1.5 PROBLEMS AFFECTING THE SCHEME

The program (SIWES) has encountered a lot of problems in recent times and
this has affected its growth and development. Below are some of the problems;

I. Employers hardly have time to impact knowledge to the students.

II. There is inadequate supervision due to inadequate funding which

makes students unserious.

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III. The funding system is inadequate and that reduces the student’s
capability and motivation to work.

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 CHAPTTER TWO

BRIEF HISTORY OF THE COMPANY

2.1 PEE DRILLING COMPANY NIGERIA LIMITED

Pee drilling is a privately owned company established in the year 2002 and
incorporated in 2003 by a geoscientist and engineer for the sole purpose of
providing consultancy services in the field of earth science. The company was
founded by Mr Chinedu Egwuekwe and managed by Mr Onyekuba Peter.

Pee drilling as an engineering company is actively involved in services such as

building, civil maintenance / mechanical and spare parts, consultancy and
general contractor. As an industrial venture, the management of the company
are aware of the dangers and hazards to which workers and even equipment are
exposed to. The company is concerned about the community affairs, safety,
health environment and security policy of its workers. The preservation of the
environment and its inhabitants is an object of concern to the company.

2.2 PURPOSE AND OBJECTIVES

(1) Provision of water and sanitation facilities in the community

(2) Hygiene and health education of local communities

(3) Increased access to safe water sources through provision of water

facilities.

2.3 PROFESSIONAL SERVICES

1. General contract administration

2. Onsite supervision of contract handling projects

3. Borehole drilling services

4. Construction services

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5. Provision of operational report for ongoing projects

6. Provision of independent geo-science services, reconnaissance,

feasibility and projects expansion surveys.

2.4 ORGANISATIONAL STRUCTURE

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 CHAPTER THREE
INTRODUCTION AND GENERAL OVERVIEW ONGROUND WATER
OCCURRENCE AND EXPLORATION

3.0 OVERVIEW OF HYDROGEOLOGIC CYCLE

Figure 2: HYDROLOGIC CYCLE

The hydrologic cycle is defined as the set of reservoirs and fluxes which hold
and move water through the atmosphere, on the surface, and in the subsurface
of the Earth with the exception of minor amounts of extraterrestrial water
brought in by comets, and small amounts of water vapour that are lost to outer
space at the upper reaches of the atmosphere, there is a constant volume of
water in the entire water cycle.

Within the cycle, there are various reservoirs holding water and various
processes that move water within reservoirs and from one reservoir to the next.

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Reservoirs in the water cycle include the oceans, atmosphere, rivers, freshwater
lakes, the unsaturated soil moisture, the saturated groundwater, connate water
in deep sedimentary rocks, magmatic water from the mantle, water in the ice
caps and glaciers (the cryosphere), and water in plants and animals (the
biosphere).

The fluxes are all the processes that move water from one reservoir to the next
(eg. Evaporation, infilteration) or within a reservoir (e.g. groundwater flow,
ocean currents).

3.1 GROUND WATER OCCURENCE

Ground water is water which exists beneath the surface in the open pore space,
and fractures in rocks. It is water which permeates from the top surface and
stored in porous subsurface lithology.

3.2 AQUIFER

An aquifer is a body of saturated rock through which water can easily move.
Aquifer must be both permeable and porous and include such rock types as
sandstone, conglomerates, fractured limestone and unconsolidated sand and
gravel. Fractured volcanic rocks such as columnar basalts also make good
aquifer. In other for a well or borehole to be productive, it must be drilled into
an aquifer. Rocks such as granite and schist are generally poor aquifers because
they have very low porosity. However, if these rocks are highly fractured, they
make good aquifers.

3.2.1 TYPES OF ACQUIFERS

1) CONFINED ACQUIFER

This aquifer is also known as artesian aquifers. This is an aquifer that is overlain
and underlain by relatively impermeable rock layer that limits ground water

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movement into or out of the aquifer, and is under pressure greater than the
atmospheric pressure.

2) UNCONFINED ACQUIFER

This aquifer unlike the confinedaquifer is located near the surface and is not
overland by an impermeable layer above the water table but is seated on top of
an impermeable layer. Thisaquifer is more prone to contamination from the
surface and the level of the water table varies from the rate of recharge or
discharge and permeability of the aquifer.

3) AQUITARD

This is a semi permeable rock formation that transmutes water in a very slow
rate. Its rate of transmission of water is slow and yield insufficient thereby,
making pumping of water impossible.

4) ACQUIFUGE: This is a geologic formation that is neither permeable nor

porous. The pour spaces are not connected, therefore can neither transmute store
water.

5) AQUICLUDE

These are low porosity and permeability rocks that acts as a barrier to the flow
of groundwater. They have good storage capacity and poor transitivity.

3.2.2 PROPERTIES OF AN AQUIFER

1) POROSITY: Total porosity (n) is the ability of an aquifer to store water so

that it is expressed by ratio in percent of the volume of void space to the total
volume of sediments or total rock volume. i.e., n%= total volume – volume of
solids * 100. Generally, total porosity is expressed as a percentage. The voids
are not necessarily interconnected and the water is not always free to flow
within the rock

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2) STORATIVITY: Storativity or storage co-efficient is the volume of water
released from storage per unit decline in hydraulic head in the aquifer. It is a
dimensionless quantity and ranges between 0 and the effective porosity of the
aquifer. For unconfined aquifer or aquitard, storativity is the vertically
integrated specific storage value. For an unconfined aquifer, storativity is
approximately equal to the specific yield
3) TRANSMISSIVITY: it is a measure of amount of water that can be
transmitted horizontally through an aquifer unit by the full saturated thickness
of the aquifer under a hydraulic gradient of 1.

T =Kb

3.3 BOREHOLE DRILLING

A borehole is a well drilled hole into the depth of the earth in the view of
exploring underground water for domestic or industrial use. It can also be
defined as a narrow shaft bored in the ground vertically or horizontally for
extraction of water or other liquids such as petroleum or naturals gas. Borehole
can be drilled by manual and mechanical means using chemicals and drill bits
which breakup earth materials while the chemicals push the cuttings outside to
the surface .A lot of process and precautions are normally put in place to
achieve a successful borehole.

3.4 PREDRILLING PROCESSES

These are the early work or the early stages of drilling process which are been
done on an area before the main drilling commences, these includes;

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fig.. starting the drilling engine

3.4.1 SITESELECTION: the procedure for this process involves,

 Surveying of area to know the best location for the borehole for easy
access to the people.
 Locating nearby sucker pits in the area and if it’s around the borehole
location, checking for pre-existing pits or holes in the environment in
other to prevent any sort of contamination to the borehole.

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3.4.2 GEOPHYSICAL SURVEY
Geophysical surveying provides a relatively, rapid and cost-effective means of
deriving aerially distributed information of the subsurface geology. Many
geophysical methods finds application in locating and defining subsurface water
(groundwater resources). They provide rapid information on the geological
structure and the prevailing lithology of a region. Commonly used methods for
groundwater investigations are the;

I. Electrical resistivity method

II. Seismic refraction
III. Electromagnetic (EM)
IV. Very low frequency (VLF) EM method
3.5 GEOPHYSICAL EMPLOYED AT PEE DRILLING.

At Pee drilling, electrical resistivity is employed and adopted in the delineation

of horizontal and vertical discontinuities in the electrical properties of the
ground.

Electrical resistivity method is useful to investigate the nature of subsurface

formations by studying the variations in their resistance to flow of electrical
current and hence determine the occurrence of groundwater. The objectives of
this method in the field of groundwater exploration are to locate groundwater
bearing formations, estimation of depth to the water table, thickness and lateral
extent of aquifers, depth to bed rock, delineation of weathered zone, structures
and stratigraphic conditions.

Two main types of procedures are employed in Electrical resistivity survey

 Vertical Electrical Sounding

 Horizontal Profiling
Vertical Electrical sounding technique is employed in pee drilling to determine
groundwater potential. In this technique, vertical variations in the ground
apparent resistivity are measured with respect to a fixed centre of array. The
survey is carried out by gradually expanding or increasing the electrode spacing
about a fixed centre of the array. Information like the resistivity value,
thickness, depth and structural deformation of the study area are revealed and
based on these geoelectric parameters recommendations are made.

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3.5.1 BASIC PRINCIPLES OF ELECTRICAL RESISTIVITY METHOD

Basically, the electrical resistivity method involves the passage of electricity

current (using D.C or low frequency A.C current) into the subsurface, through
two electrodes (the current electrodes). The potential difference is measured
between another pair of electrode (the potential electrodes), which may or may
not be within the current electrodes depending on the electrode array in use.
Actual resistivity of subsurface layer is determined from ground apparent
resistivity, which is computed from the measurement of current and potential
difference between the electrodes pair placed on the surface. In which the
apparent resistivity can be calculated as

Pa = KR Where:

ρa = Apparent resistivity in (Ωm)

K = Geometric factor.

R = Resistance in (Ω)

3.5.2 SCHLUMBERGER CONFIGURATION

In this array, all the four electrodes are placed along a common line as with the
Wenner array but they are not spaced equally where the distance between the
inner two, which are used to

measure voltage is kept less than one fifth the distance between the current
electrodes. this survey measure vertical variation of Earth resistivity as a

function of depth, and symmetrical array method is adopted.

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Fig.2schlumberger configuration

electric constant t
Where: ρa apparent resistivity

AB=Current electrode
V/I= resistance

MN=potential difference electrodes

a= Electrode spacing

X=Point of investigation (Midpoint)

3.5.3 IMPORTANT OF ELECTRICAL RESISTIVITY METHOD IN

GROUNDWATER EXPLORATION

Important of this method to groundwater exploration are as follows;

 are to locate groundwater bearing formations, estimation of depth to the

water table, thickness and lateral extent of aquifers, depth to bed rock,
delineation of weathered zone, structures and stratigraphic conditions.
 Determination of saline zones and fresh/saline water interface in the
coastal areas.
 Mapping of groundwater flow direction.
 Direct location of subsurface water through mapping of the water table.
Indirect location of potential aquifer such as weathered zone, porous and
permeable sandstones, alluvium deposits and sand gravel within clay
deposit, Etc. mapping of geological structures that are favourable to
groundwater accumulation, such as fractures, basement depressions,
buried channels, sand lenses and network of joints.
3.5.4 INSTRUMENTS AND THEIR USE IN GEOPHYSICAL SURVEY

TERRAMETER: This is an instrument used in carrying out electrical

resistivity survey of an area of interest, basically both in the sedimentary and
basement complex. It is used to read the resistivity of the rock or any viable
material in the subsurface when a current direct or low voltage frequent current
is sent into the earth. The CAMPUS OMEGA Terrameter was used during the
period of my training.

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 Fig.2.1
campus omega resistivity meter

CABLE REELS: These are used for connecting the electrodes to the
terrameter. Usually four cables are used, two for current and the other two for
potential difference. The current cables are usually black or blue colour while
the potential cables are red in colour. The cables are reeled around a wheel of
steel; the cables are fitted with crocodile clips for easy and firm connection.

Fig.2.2 cable reels.

TAPE RULE/MEASURING TAPES: A round narrow band of woven fabric,

which is used for linear measurement, each type rule is about 50cm long

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Fig.2.3 measuring tape

ELECTRODES: These are rods which are about 45cm to 55cm long made of
metal. They are four in number, two for current and the other two potential.
They have a very sharp pointed end for easy penetration into the earth with the
other end flat and blunt. The electrodes are placed strategically during
geophysical survey, which also depend on electrode configuration used.

Fig.2.4: electrodes

HAMMERS: An handheld tool consisting of a solid, heavy metal which is used

in driving electrodes into ground. The handle is usually light and it is made of
wood. The metal head weigh about 2kg.

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Fig.2.5: hammer

3.5.5 SITE PREPARATION: After the final site for the borehole has been
selected, the site is prepared before drilling commences in the following ways.

a) CLEARING OF THE DRILLING SITE: This is done by cutting the bush

and stumping in order to create chance for movement of the rig or the tripod
machine and equipment to the site.

b) TRANSPORTATION OF THE DRILLING EQUIPMENT: This can be

done manually or by using towing van to drag the equipment to the site like in
the case of the rig of M&W 100 and 250 models and the tripod is carried to the
site. The rig is motorised and is driven down to the site.

c) CONSTRUCTION OF MUD PIT, SETTLING PIT, SAMPLE PIT AND

MUD CHANNEL OR FLOW LINE:

 THE MUDPIT. The mud pit is a four dimensional pit, about 8ft long,7ft
wide and 6ft deep, which is dug using a shovel. It's where the mud is
mixed with chemicals before it is pumped into the well through the
swevil head and into the drill pipes. The walls of the mudpit is plastered
with cement to prevent loss of water to the surrounding.The suction hose
and the mud mixing hose are always lowered into it.
 THE SETTLING/SAMPLE PIT. The settling and sample pit are
smaller versions of the mud pit which may or may not be plastered, they
are for accumulation of cuttings and to avoid them going into the mud
pit. The cuttings settle into the settling pit and samples are collected from

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 the sample pit.

FIGURE 3: Mud pit/flow channel

3.6 DRILLING PROCESS: Drilling is an act of combining mechanical action

with hydraulic action to produce a hole of given diameter.

It is important to know the reason or purpose why the borehole/well is being

constructed before the construction of a borehole/well, therefore by determining
the type and size of the well to be constructed. The construction of a borehole
depends on the following factors;

I. Purpose of the borehole

II. Geological factors

III. Economic factors

IV. The quantity of water required and ground water depth of the area

3.6.1 BOREHOLE DRILLING METHOD

There are two major methods of drilling boreholes.

 Mud rotary drilling method: In mud rotary drilling, fluid is pumped down
the hollow drill pipe called kelly, and forced out of jets in the drill bit,
that fluid then carries the cuttings or cut materials through hole and up to

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 the surface and mud is reused through a pit, and this drilling method is
done on unconsolidated rocks.
 Air rotary drilling method: is a method used to drill deep boreholes in
rock formations (consolidated rock). Borehole advancement is achieved
by rapid rotation of a drill bit which is mounted at end of the drill pipe.
The drill bit cut the formation into pieces called cuttings. This method
utilizes air as a circulating medium to cool the drill bit, bring drill
cuttings to the surface and maintain borehole integrity

This can be excavated by simple hand drilling method or machine drilling

methods.

(1) Simple hand drilling methods like:

I. Driving

II. Jetting

III. Hand percussion

IV. Sludging

V. Angering method

(2) Machine drilling methods like:

I. Rotary method

II. Percussion

During the period of my industrial training, the rotary method was used,
using Giant rig and manual (Tripod) type.

The drilling method that will be suitable for the construction of a borehole
depends on the geologic conditions at the proposed site. It is known that the
rotary method of drilling is most suitable where there is an unconsolidated
formation e.g. south-eastern Nigeria. However it is recommended to study
the lithology of the proposed site before the commencement of the borehole
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 construction. It is important to note that the number of days required to
construct a borehole depends on the efficiency of the machine, depth to be
drilled and lithology of the site.

 ROTARY METHOD
Rotary method is of two types and it is based on their sources of power though
they have the same mechanism of operation. They are;

(1) Manual (Tripod) type; this has human beings as the power source that
rotates the drilling bit.

(2) Machine type; this method has the ‘’RIG’’ as the power source that
rotates the drilling bit.

In this method, drilling is done by rotating a drill pipe with a drill bit attached
to it by the help of a hydraulic driving force. When the bit penetrates the
formation with the drill pipe fixed to it, it cuts and breaks up the rock materials
(cuttings). Mud pump is used to pump the drilling fluid from the mud pit into
the hole. This helps to bring cuttings up to the surface.

However there may be modification of methods to improve the efficiency of the

machine as the terrain gets harder.

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fig.... sample collection

3.7 BOREHOLE DRILLING EQUIPMENT AND THEIR USES

These are the machinery, equipments and materials used to carry out the
drilling, pump testing, headwork construction etc.They are to be mobilized,
handled, transported and stored in accordance with recommendation for the
work.

1. DRIILING RIG: drilling rig is a machine that creates holes in the earth’s
subsurface. Drilling rigs can be mobile equipments mounted on trucks,
trailers, tracks etc. They are used to drill water wells, oil wells, or natural gas
extraction wells.

There are of four main categories.

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 Mechanical rig- the rig uses torque converters, clutches, and
transmissions powered by its own engines, often diesel.
An example is the tripod

Figure 4:Mechanical Rig

 Manual rig
 Hydraulic rig- uses hydraulic power primarily.
 Electric rig- the major terms of machinery are driven by electric
motors, usually internal with power generated on-site using
combustion engine.

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fig; Towing rig

2. DRILL BIT:
Drill bit is a heavy tool designed to cut into the subsurface using a
mechanical force.
They are of different types
 Diamond drill bit: they have a single fixed head that contains many
small diamonds, as the bits turns, the diamond cuts the rock, they also
have nozzle to wash away the broken pieces of the rock.

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 Figure 5: diamond drill bit
 Drag bit: it has a shearing action which is widely used in cutting of sand,
clay and soft materials, and does not work well in coarse gravel or hard
rock formation they have short blades that can be replaced.
 Reamer bit: is later used to widen the hole to about 6 inches, attached to
the drill pipe screwing just above the drill bit, used in sandy soil or clay.
 Fixed cutter bits: a set of blades with very hard cutting elements mostly
natural or synthetic diamond to remove material by scraping or grinding
action as it is being rotated.
3. Rotary System: wells and boreholes are drilled by pipes and bits rotation;
therefore it is very important to have a very efficient rotation system which
includes the swivel head, Kelly, rotary drive and rotary table. The working
principle of the rotary system is the Kelly connected to the drill pipe drove
by the rotary table and then to the drill strings and can be rotated for drilling.

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fig.. turning table

 Swivel head: this is attached to the bottom of the travelling block

and allows the drill strings to rotate smoothly.

 Kelly: this is a rectangular or hexagonal shaped section of pipe that

is attached to the swivel and fits to the matching slot in the rotary
table. It is also the first pipe that lowered into the hole during
drilling.

4. Rotary Table: this is a mechanical device on a drilling rig that provides a

clockwise rotational force to the drill string to facilitate the process of
drilling a borehole

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5. Drill Stems: are round steel tubes about 30feet long with a diameter from 4
to 5 inches, it has threaded connections on each end that allows the pipes to
be joined together to form longer sections.

Figure 6: Drilling pipe

6. Pipe wrench: this is a type of adjuster that is used for gripping, loosening
and tightening of the drill pipes to the drill bits and then to other pipes during
drilling.
7. Mud Pump: A mud pump is a reciprocating pump design to circulate
drilling fluid under high pressure down the drill string back to the annulus
and out.

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 Figure 7: Mud Pump

8. Sample Box: this is a large box in which has compartments or an empty

box in which drill cuttings from the annulus of the hole are collected at
different feet and packed at intervals for noting the formations until the
aquifer zone is reached and also to make other important reference as to the
casing of the hole etc.

Figure 8: Sample box

9. Marine Rope: a very strong hard material of variable length used in sending
down pipes and submersible pumps.

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Figure 9: Marine rope

10.Rig Mast: This is used in setting or positioning drilling rods or pipe

11.Chain Turn: This is used in turning the rods in other to remove or install
another rod.
12.Kelly hose: also known as mud or rotary hose, which is flexible, steel
reinforced, high pressure hose that connects the stand pipe to the Kelly pipe
and allows free vertical movement of the Kelly while facilitating the flow of
drilling fluid through the system.

13.Mixing bucket: used to mix chemicals in definite proportions before

transferring into the mud pit.

14.Casing pipes: This is used for post drilling operation, it functions as a

channel through which water gets to the surface and also helps to hold the
wall of the hole to prevent collapse of the hole after drilling. They are of two
main types; the steel pipes with Johnson stainless screen and the
polyvinylchloride (PVC) casing pipes with PVC screen.

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 Figure 10: Casing Pipe

15.Spade: used for digging the pits.

16.Shovel: for sample collections from the mud pit

17.Submersible Pump: This has a hermetically sealed motor close-coupled to

the pump body. The whole assembly is submerged in the fluid pump out
water.

Figure 11: Submersible Pump

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18.Clamp: is a fastening device used to hold and secure the drill pipes when
applying inward pressure to it

19. Rig Hammer: Helps in setting the rods into the drilling spot.

20. Jack: this is used for raising

21. Riser pipes: This is a long tube made out of plastic or metal used on
carrying water to surface

Figure 12: RISER PIPES

3.8CHEMICALS USED IN DRIILING

Some chemicals are used during drilling as they help the drilling process.
These chemicals are:

1)BENTONITE (Aquagel): it is a brownish fine solid particle; it increases the

viscosity of the drilling fluid.

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Figure 13: Bentonite

2)EXTENDER (Magnoflux): it helps in making the slurry (drilling fluid/mud)

thick for higher pressure as you drill when other chemicals becomes in active. It
is also a whitish fine solid particle.

Figure 14: Extender

3) ANTISOL: It is milky in color, fine solid particles. This chemical helps in
flushing out the drilling cuttings and sealing the walls of the mud pit

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 Figure 15: Antisol

3.9 GUIDLINES TO STOP DRILLING

Careful observation to drilling sometimes reveals one or more of the following

signs indicating that a good water-bearing layer has been reached:

1)Characteristics of the cutting

The cutting may indicate the drill bit has hit a zone of sand and/or gravel
(formations which usually produce abundant volumes of water if they are
saturated). This is the most widely used indicator and requires continuous,
careful sampling of drill cuttings.

2) Rate of penetration:

There’s often significant increase in the speed with which the hole is being
drilled when permeable sand aquifer is released.

When drilling into the gravel aquifer, the gravel will often cause the bit to
bounce.

3) Depth comparison to other previously dug aquifer.

4) Characteristics of the drilling fluid (it becomes thinner) and the temperature
of the drilling fluid drop drastically.

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3.10POST DRILLING OPERATION
When the drilling has been completed then the post drilling process commences.
This is done to make the borehole ready for both domestic and industrial use.
Post drilling operations include:

3.10.1 FLUSHING AND REMOVAL OF DRILLING STEMS.

When the aquifer has been reached, the drilling stems are pulled out and
flushing is done to remove any remaining cuttings in the borehole.

3.10.2 BLIND CASING AND SCREEN INSTALLATION

This process is done to create a channel for the tapped water to flow upwards. It
is divided into two which are screen installation and blind casing installation.
The blind casing installation prevents the sides of the hole from caving and
unwanted fluid from entering the borehole and contaminating the water while
the Screen installation serves as a means through which sand free water enters
the borehole.

 CREATIMG THE BOTTOM SUMP

Before the process of installation occurs, the bottom sump is constructed

locally by cutting the pipe in triangular teeth like shape, melting the PVC pipe
in order to close the pipe. The bottom sump is filled with cement and allowed to
set a hole is made at the both ends of the bottom sump and the marine rope is
attached to it before lowering it.

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  INSTALLATION OF SCREEN AND BLIND CASING

Screen is casing pipe that has been suited/sliced (with a diameter 0.05mm) to
prevent sand or contamination in other words it serves as a filter. Screen casing
includes PVC screen pipes, metal screens and Johnson filter screen. The screen
ranges from 14ft to 20ft in length and the width varies between 0.25mm and
4mm while the diameter is selected based on the desired well yield and
saturated aquifer thickness. Screens to be used are calculated to the static water
level of the well.

After the screen casings are lowered down into the borehole, then the
installation of the blind casing pipes until the entire length of the borehole has
been screened and cased. The blind casing has no openings. They are connected
to the screen and do not allow passage of water from the water bearing zone .It
serves as a channel for water coming from the aquifer zone through the screen.
Borehole screens should be placed next to the water producing horizon for the
effective performance of the borehole. It is vital to get the calculations right in
order not to seal the water producing horizon

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3.10.3BACKWASHING

This is done to improve for efficiency of the borehole and open the pores of the
screen. This operation is carried out by connecting the hose of the tanker that
has a compressor to the Kelly that is inserted into the hole; water is forced into
the borehole using a sack or sacks of cement bag to close the space between the
annulus and Kelly to increase the pressure of the water. With the help of
pressure of the water, cuttings and chemicals are forced out from the borehole
hole to the surface. This operation/process is continued for a period of time (2-3
hours).

3.10.4INSTALLATION OF FILTER PACK (GRAVEL PACKING)

This is done by using small grained gravel into the annular space and then
allowed to settle into the upward flowing water. It helps the filtered materials
from bridging and keeps the fines from settling. The feeler is being used to
know when the filter pack has reached the desired depth which can be 3m above
the screen or 10-20ft below the ground surface. Filter pack is used to make sure
that fine particles do not enter the borehole and also to increase the effective
hydraulic diameter of the well. . The filter pack consists of graded gravel; we
used standard gravel called WHITE RIVER RICE GRAVEL found in the
bottom of the river. They are standard because they are rounded in shape and do

35
not react with the water (that is they can’t cause contamination or cause
coloration.

Fig. 3.1.2 driller gravel packing the borehole

3.10.5 GROUTING
This is the mixture of sand, cement and water used to seal the space between
the casing and the borehole walls. This cement grouting is to prevent damage or
contamination of the borehole by surface materials.

36
3.10.6PUMP INSTALLATION

This involves lowering the pump lifts into the well. The depth at which the
pump is being installed in the well is basically determined by the aquifer static
water level gotten from the well. A marine rope and riser pipes is used to lower
the pump into the well. Reduction in yield might occur if the pump is not
installed at a considerable depth which is the static water level of the well.

lowering pump and raisers into the well

37
PRECAUTION WHEN INSTALLING THE PUMP
(1) A good power source was connected to the pump border to maximize its
efficiency and prevents the burning of the pump.

(2) We ensured that the static water level of the well is known.

(3) We ensured that the pump was not lowered into the screen.

3.10.7PUMP TEST: This is the continuous pumping of the borehole water for
a period of time in order to make the borehole water clean enough for usage.
This process is carried out after the installation of the submersible pump.
3.11ADVANTAGES OF BOREHOLE CONSTRUCTION

I. Quick and cheaper to sink than hand dug wells.

II. Less susceptible to contamination.
III. No dewatering during sinking required.
IV. Less lining material required.
V. Safer in construction and use.

3.12 DISADVANTAGES OF BOREHOLE CONSTUCTION

I. Over exploitation may have adverse effect on the environment

II. Lack of skilled staff and experts required for drilling
III. Arsenic pollution may occur

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 CHAPTER FOUR

FIELD OPERATIONS (SITE WORKED ON)

4.1 SITE ONE

LOCATION Book foundation ifite awka

FORMATION IMO SHALE
DEPTH DRILLED 868ft
NO OF CASING PIPES USED 54
NO OF SCREENS USED 2
NO OF RISER PIPES USED 13
WORK DURATION Three weeks

Depth(ft) Lithology type

0-57 Laterite
57-85 Coarse grained

85-356.7 Medium grained

356.7-678 Fine sand

678-868 Very fine sand

4.2 SITE TWO

LOCATION Chief Anunobi drive behind stanel agu awka

FORMATION IMO SHALE
DEPTH DRILLED 744.7ft
NO OF CASING PIPES USED 51
NO OF SCREENS USED 2
NO OF RISER PIPES USED 11
WORK DURATION TWO WEEKS

DEPT(FT) LITHOLOGY TYPE

39
 COARSE GRAVEL
0-22

CLAY + SAND
22-42.4

SHALE
42.4-661.7

FINE SAND
661.7-744

4.3 SITE THREE

LOCATION New york road behind glass house amaenyi

FORMATION IMO SHALE
DEPTH DRILLED 170ft
NO OF CASING PIPES USED 14
NO OF SCREENS USED 6
NO OF RISER PIPES USED 11
WORK DURATION TWO WEEKS

DEPT (FT) LITHOLOGY

0-22 COARSE SAND
22-64.1 SHALE+CLAY+IRONE
STONE
64.1-170 Very fine sand
------------- -----------------
-------------- -----------------

4.4 SITE FOUR

LOCATION Unizik at faculty of education

FORMATION IMO SHALE
DEPTH DRILLED 544.3ft
NO OF CASING PIPES USED 37
NO OF SCREENS USED 2
NO OF RISER PIPES USED 12
WORK DURATION Three weeks

40
 Depth(ft) Lithology type

0-57 Laterite
57-85 Coarse grained

85-356.7 Medium grained

356.7-478 Fine sand

478-544.3 Very fine sand

4.5 SITE FIVE

LOCATION Udi Enugu state

FORMATION IMO SHALE
DEPTH DRILLED 550ft
NO OF CASING PIPES USED 38
NO OF SCREENS USED 2
NO OF RISER PIPES USED ---
WORK DURATION TWO WEEKS

DEPT(FT) LITHOLOGY TYPE

COARSE GRAVEL
0-22

CLAY + SAND
22-42.4

SHALE
42.4-330

FINE SAND
330-550

4.6 SITE SIX

LOCATION Unizik Deeper life church unizik behind st

teresa
FORMATION IMO SHALE
DEPTH DRILLED 551.7ft
NO OF CASING PIPES USED 42

41
 NO OF SCREENS USED 2
NO OF RISER PIPES USED 13
WORK DURATION TWO WEEKS

DEPT (FT) LITHOLOGY

0-22 COARSE SAND
22-64.1 SHALE+CLAY+IRONE
STONE
64.1-220 SAND
220-415.5 FINE SAND
415.5-551.7 VERY FINE SAND

4.7 PROBLEMS ENCOUNTERED AND SOLUTIONS

1)LOSS OF CIRCULATION

This is a situation of excessive loss of fluid and it happens when the drill bit encounters a
vacuum or a cave. Here the drilling mud runs into the vacuum or cave and this stops cutting
from being carried out which will lead to the pipe being stuck.

SOLUTION

Material like fibre, sawdust, are mixed in the mud pit with bentonite and sent into the hole
to seal the pore spaces, cave or vacuum created in the formation.

2)PIPE STUCK

This occurred where the normal rotation of the drilling string stopped due to expansion of
clay materials surrounding the bit in the hole, backfilling or reduction in the pressure of the
mud.

SOLUTION

Introduction of more drilling fluid thickened by gel or polymer and reintroduced into the
well and then rotate and pulled gradually. The mud lubricates the bit to remove the cuttings
holdings it.

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3)BRIDGING IN WELL

This takes place where the casing pipe and the screen could not reach the desired depth due
to blockage. This can as well be caused by the swelling of the clay in the well or using of the
wrong diameter of casing pipe.

SOLUTION

The borehole is rimmed with diameter of large bit.

4) BREAKAGE OF PIPE IN THE BOREHOLE

During drilling, the drilling pipe broke inside the borehole making it impossible to drill
further.

SOLUTION

A fishing barrel was used to fish out the broken pipe from the bor

43
 CHAPTER FIVE

5.1 CONCLUSION

My industrial training with Pee drilling company Nigeria limited has exposed me to the
practical application of soil and water engineering principles to borehole drilling, well
development and completion.

In conclusion, my borehole drilling experience has been both enlightening and rewarding.
Throughout the process, I gained a deep appreciation for the intricacies and challenges
involved in accessing groundwater resources. From the initial site assessment to the actual
drilling and installation of the borehole, every step required careful planning, technical
expertise, and a dedicated team.

Witnessing the drilling rig in action, penetrating the earth's surface and reaching depths
previously unexplored, was a remarkable sight. The anticipation and excitement grew as we
neared the desired aquifer, knowing that this borehole would provide a sustainable and
reliable water source for years to come.

The collaborative efforts of geologists, hydrologists, engineers, and drilling personnel were
instrumental in ensuring the success of the project. Their knowledge and experience helped
mitigate potential risks and maximize the efficiency of the drilling process. It was evident
that their commitment to delivering a high-quality borehole was unwavering.

Beyond the technical aspects, the borehole drilling experience taught me the value of water
as a precious resource. Seeing firsthand the challenges faced by communities without access
to clean water underscored the importance of such projects. The provision of a borehole
not only enhances the quality of life but also promotes health, sanitation, and economic
development.

Moreover, this experience highlighted the need for responsible water management. It
emphasized the significance of monitoring and maintaining the borehole to ensure its long-
term functionality. Regular water quality testing, maintenance of the pump system, and
community involvement are vital for sustaining the benefits derived from the borehole.

44
In retrospect, my borehole drilling experience has been an eye-opening journey. It has
deepened my understanding of water resource management, enhanced my appreciation for
the expertise of professionals in the field, and reinforced the significance of sustainable
solutions to address water scarcity.

As I reflect on this experience, I am inspired to continue supporting initiatives that promote

access to clean water. Borehole drilling is not merely a technical endeavor; it is a catalyst for
positive change, improving lives, and empowering communities. I am grateful for the
opportunity to be part of this transformative process, and I look forward to contributing to
future endeavors aimed at ensuring water security for all.

RECOMMENDATION

It is recommended that federal government should make appropriate funds available for the
program

It is recommended that the university management to review the duration of the program

It should be legislated that only licensed contractors and professionals are to drill boreholes in
the country. This will help in the collation of litho-logs and proper documentation of the
available geological and geophysical data for detailed and comprehensive academic work on
our aquifers.

It is also recommended that groundwater monitoring should be conducted regularly to assess

the aquifer.

To the University

The university should form a strong link with the industry via the departments to solve the
problem of student’s placement

It is recommended that federal government should make appropriate funds available for the
program

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