Oil and Natural Gas Corporation (ONGC) is India's largest oil and gas exploration and production company, producing around 69% of India's crude oil. It is headquartered in Dehradun and is a Public Sector Undertaking owned by the Government of India. ONGC has discovered 6 of India's 7 major sedimentary basins and owns and operates over 11,000 km of pipelines. It is involved in oil and gas exploration projects in 26 sedimentary basins in India as well as 17 international projects through its subsidiary ONGC Videsh. The Ahmedabad asset of ONGC receives power from Torrent Power and distributes it to nearby locations using equipment such as transformers, circuit breakers,

1. 1
Chapter 1
INTRODUCTION TO COMPANY
Oil and Natural Gas Corporation Limited (ONGC) is an Indian multinational oil and gas
company headquartered in Dehradun, Uttarakhand, India. It is a Public Sector Undertaking
(PSU) of the Government of India, under the administrative control of the Ministry of Petroleum
and Natural Gas. It is India's largest oil and gas exploration and production company. It produces
around 69% of India's crude oil (equivalent to around 30% of the country's total demand) and
around 62% of its natural gas .On 31 March 2013, its market capitalization was INR 2.6 trillion
(US$48.98 billion ), making it India's second largest publicly traded company. In a government
survey for FY 2011–12, it was ranked as the largest profit making PSU in India. ONGC has been
ranked 357th in the Fortune Global 500 list of the world's biggest corporations for the year 2012.
It is ranked 17th among the Top 250 Global Energy Companies by plats’ . ONGC was founded
on 14 August 1956 by Government of India, which currently holds a 68.94% equity stake .
It is involved in exploring for an exploiting hydrocarbon in 26 sedimentary basins of India, and
owns and operates over 11,000 kilometers of pipelines in the country. Its international subsidiary
ONGC Videsh currently has projects in 17 countries. ONGC has discovered 6 of the 7
commercially producing Indian Basins, in the last 50 years, adding over 7.1 billion tones of In-
place Oil & Gas volume of hydrocarbons in Indian basins. Against a global decline of production
from matured fields, ONGC has maintained production from its brown fields like Mumbai High,
with the help of aggressive investments in various IOR (Improved Oil Recovery) and EOR
(Enhanced Oil Recovery) schemes. ONGC has many matured fields with a current recovery
Fig 1.1 logo of company

2. 2
factor of 25–33%. Its Reserve Replacement Ratio for between 2005 and 2013, has been more
than one. During FY 2012–13, ONGC had to share the highest ever under-recovery of INR 494.2
million (an increase of INR 49.6 million over the previous financial year) towards the under -
recoveries of Oil Marketing Companies (IOC, BPCL and HPCL).
Maharatna ONGC is the largest producer of crude oil and natural gas in India, contributing
around 70 percent of Indian domestic production.
I got training from Ahmedabad asset, Sabarmati Gujarat
Fig 1.2 Ahmedabad asset, Sabarmati

3. 3
Chapter 2
MAINTENANCE AND FAULT ANALYSIS
2.1 Definition:
A combination of any actions carried out to retain an item in or restore it to, an acceptable
condition is called maintenance. It ensures the quality, reliability, availability and safety of
equipment’s for optimum level of performance.
Maintenance management:
Maintenance management is the art of getting things done through people to maintain and
enhance the useful service life of equipment at acceptable condition with minimum cost.
Types of maintenance
1. Breakdown maintenance
It means that people waits until equipment fails and repair it. Such a thing could be used when
the equipment failure does not significantly affect the operation or production or generate any
significant loss other than repair cost.
2. Preventive maintenance
It is a daily maintenance (cleaning inspection, oiling and re- tightening), design to retain the
healthy condition of equipment and prevent failure through the prevention of deterioration
periodic inspection or equipment condition diagnosis to measure deterioration.
3. Corrective maintenance
It improves equipment and its components so that preventive maintenance can be carried out
reliably equipment with design weakness must be redesigned to improve reliability or improving
maintainability.
4. Maintenance prevention

4. 4
It indicates the design of a new equipment. Weakness of current machines are sufficiently
studied /on site information leading to failure prevention, easier maintenance and prevents
defects, safety and case of manufacturing and are incorporated before commissioning a new
equipment.
2.2 Fault analysis:
1. Electrical faults
Stator winding short circuit, broken rotor bar, broken end rings, bearing jam, inverter failure etc.
With electrical faults it sends to the electrical workshop.
2. Mechanical faults
Rotor eccentricity, bearing faults, shaft misalignment, load faults
(unbalance gearbox or general failure) etc.
With mechanical faults machine send to the mechanical workshop.
Theoretical study of mechanical fault effects on stator current. The key assumption for the
development of the theoretical models is that mechanical faults mainly produce two effects on
induction machines additional torque oscillations at characteristics frequency or air gap
eccentricity.

5. 5
Chapter 3
UNDER REPAIR
3.1 Motor
Principle:
(Rotating magnetic field) When rotating magnetic field cuts the rotor
conductors, hence circulating current induced in these short circuited
rotor conductors. Due to interaction of the magnetic field and these
circulating currents the rotor starts rotates and continuous its rotation.
This is induction motor which is known as asynchronous motor runs at a
speed lesser than synchronous speed, the rotating torque, and speed is
governed by varying the slip which gives the difference between
synchronous speed Ns, rotor speed Nr S= Ns-Nr/Ns
Squirrel cage induction motor & application:
A squirrel-cage rotor is the rotating part (rotor) used in the most common form of AC induction
motor. It consists of a cylinder of steel with aluminum or copper conductors embedded in its
surface. An electric motor with a squirrel-cage rotor is termed a squirrel-cage motor
Applications:
Fig 3.1 motor under
maintenance
Fig 3.2 motor under repair Fig 3.3 300hp motor

6. 6
1. Cranes
2. Hoist
3. Pumps
4. Fans and blowers
5. Conveyors
6. Domestic purposes
3.2 Alternators
Principle: Induced e.m.f
A. C. (Alternating Current) Generators: An Electrical Generator is a device that produces an
Electromotive Force (e.m.f.) by changing the number of Magnetic Flux Lines (Lines of Force),
Φ, passing through a Wire Coil
3.3 Autotransformer
Principle:
ATS uses an auto transformer to reduce the voltage applied to a motor during start. The auto
transformer may have a number of output taps and to be setup to provide a single stage starter
typically.
Specification:
285 HP transformers
3Ph-RYB
3N-N1, N2, N3
Having capacity for voltage drop upto 40%, 60%, 80%.
Voltage drop can be vary as per load provided to it.
Fig 3.4 hoist (2 tones crane)
Fig 3.5 Autotransformer

7. 7
3.4 Welding transformers
Principle
A welding transformer is a step down transformer that has thin Primary winding with a large
number of turns and its secondary has more area of cross-section and less number of turns
ensuring less voltage and very high current in the secondary. The welding transformer reduces
the voltage from the source voltage to a lower voltage that is suitable for welding. Usually
between 15 and 45 volts. The secondary current is quit high and it may be typically 200A to
600A, but it could be much higher.
They are of two types basically used.
1. Oil Welding Transformer
2. Dry Welding Transformer
3.5 Battery charger
Principle and working:
Fig 3.6 dry welding transformer Fig 3.7 oil welding transformer

8. 8
It is the equipment by which we can charge the batteries of the
vehicles, electrical machines etc. it have two meters first is
ammeter and second is voltmeter. On the backside of charger,
it has 4 power diodes with one step down transformer. The
transformer transfers the power to the power diodes so that the
diodes will change the AC power to DC power. In the battery
charger we always try to take first series connection because it
gives as earthing to the charger. After checking that earthing is
there or not we can use parallel connection directly without
the series connection.
3.6 Oil Test
We know that oil is used for cooling and insulation purposes in transformer and other electrical
equipments to ensure that they are still fit for working. The
machine used for testing the oil which will use in a lubrication
process in a machine. Before pouring of oil in the machine first
it should tested. In the range of 0 to 10 KV then we can call, it
is as a fail, or if the oil sparks in the range 10 to 40 KV then we
call it as a pass. If it will pass then we can use it for the
lubrication. Generally the ideal oil or fresh oil pass range goes
up to 40KV. Another point for the fail oil is we can again use
by heating it at a high temperature so that the impurities from
the oil will be removed.
3.7 Starter /Engine Self Starter
1. Lucas:- 12V, need one battery for starting of the engine.
2. Delcoremy: - 24V, need two batteries for starting of engine.
Fig 3.8 battery charger under
repairing
Fig 3.9 oil test machine

9. 9
Parts: armature, commutator, auxiliary winding, main field winding, brush gear assembly and
solenoid switch.
In Lucas self starters auxiliary winding helps pinion to come out. Having less capacity to do
work than delcoremy self starter automatically pinion comes out from the auxiliary winding.
Having more capacity to do work than Lucas self starter.
3.8 Dimmer (Oil Auto Transformer)
Three phase oil cooled type continuously adjustable auto
transformer to check out the supply given to any building
transformer. It has handle to change the supply voltage according to
our need and have the walls type pipelines which is used to circulate
the air in between the pipes so that the oil in the pipes can be cooled
for better life of the transformer.
3.9 Air Compressor
An air compressor is a device that converts power (using an electric motor, diesel or gasoline
engine, etc.) into potential energy stored in pressurized air (i.e., compressed air). By one of
several methods, an air compressor forces more and more air into a storage tank, increasing the
pressure. When tank pressure reaches its upper limit the air compressor shuts off. The
Fig 3.10 delcoremy type starter Fig 3.11 pinion
Fig 3.12 dimmer

10. 10
Compressed air, then, is held in the tank until called into use. The energy contained in the
compressed air can be used for a variety of applications, utilizing the kinetic energy of the air as
it is released and the tank depressurizes. When tank pressure reaches its lower limit, the air
compressor turns on again and re-pressurizes the tank.
3.10 Fan rewinding machine
It is the machine used for rewinding of rotor of the fan
coil. First the coil is settled on machine or fixed on the
rewinding machine. Then from the bunch of the wires
some of the wires comes out and rolling on the coil as
per our requirement (12 pole-24 wires and 2 pole-4
wires). First the machine is checked by the series
connection for the checking of the earthing then after it
will be connect in parallel connection. We can also go
reverse and can stop at any time in emergency.
Fig 3.13 air compressor
Fig 3.14 fan rewinding machine

11. 11
3.11 Induction Heater for Bearing
Induction heater for bearing is used to rearrange
the bearing of rotor or machine. It can change
the size or the shape of the bearing. Firstly the
bearing is fixed in the rod then the required
temperature is set on the electric. Arc is
produced to heat the bearing, if bearing is jam
this machine is useful for it.
3.12 Winding Machine
It is a machine for making coil for the machines like-fan, cooler, motor etc. One terminal of coil
connects to the secondary of the coil but in the anticlockwise direction. In fan we using 2coil (12
poles) and in the hanging fan we are using 4 coil (24 poles)
Fig 3.15 induction heater for bearing
Fig 3.16 fan rewinding machine

12. 12
Chapter 4
ELECTRICAL PORTION
ONGC Ahmedabad asset got power from Torrent Power supply and workshop only distribute it
to three different places nearby it. SF6 circuit breaker is installed by torrent power supply.
4.1 Torrent power
Torrent Power Limited is an India- based company engaged
in the electricity generation, transmission and distribution.
Its current operations are in the states of Gujarat and
Maharashtra and Uttar Pradesh.
The company is the sole distributor of electricity to
consumers in the cities of Agra, Ahmedabad Gandhinagar
and Surat.
4.1.1 Circuit Breakers
A circuit breaker is an automatically operated electrical switch designed to protect an electrical
circuit from damage caused by over current or overload or short circuit. Its basic function is to
interrupt current flow after protective relays detect a fault. Unlike a fuse, which operates once
and then must be replaced, a circuit breaker can be reset (either manually or automatically) to
resume normal operation. Circuit breakers are made in varying sizes, from small devices that
protect an individual household appliance up to large switchgear designed to protect high voltage
circuits feeding an entire city.
SF6 circuit breaker is used to reduce sparking here.
4.1.2 HT meter
Tension is a French word for Voltage. A low-tension line is a low voltage line and a high-tension
line is a high voltage line. In India LT supply is of 400 Volts for three-phase connection and 230
Fig 4.1 supply from torrent power
limited

13. 13
Volts for single-phase connection. High tension or HT supply is applicable for bulk power
purchasers who need 11 kilo-Volts or above. Most small consumers of electricity like individual
houses, shops, small offices and smaller manufacturing units get their electricity on LT
connection. HT is applicable for bulk purchasers of electricity like industries (big manufacturing
units), big offices, Universities, hostels and even residential colonies (if the apartment complexes
purchase together in bulk). The tariff structures of most state distribution companies are different
for LT and HT.
4.1.3 VCB (Vacuum circuit breaker)
In this asset VCB is installed by ONGC, for the protection.
Vacuum circuit breakers, vacuum is used as the arc quenching
medium. Vacuum offers the highest insulation strength. So it has
far superior arc quenching properties than any other medium. For
example, when contacts of a breaker are opened in vacuum, the
interruption occurs at first current zero with dielectric strength
between the contacts building up at a rate thousands of times
higher than that obtained with other circuit breakers.
4.1.4 Battery charger
Fig 4.2 HT meter
Fig 4.3 VCB

14. 14
It charges the batteries connected to it in case if fault occurs or
circuit trips batteries supplies the power. Its one terminal is
connected to VCB and other is connected to batteries, charging can
be removed. In case if fault occurs or in case of overload, there is a
hooter present on the device started to sound loudly then VCB can
be operated manually.
It has two digital meters one is showing approximate power
charging of batteries(i.e. voltmeter) and other is ammeter.
Red light is showing it is in on condition.
4.1.5 Battery connection
There are 55 batteries connected in parallel, in case if supply is cut
batteries are used to supply power each battery is of 2.2 volts (DC
type). There are two methods of charging the batteries by battery
charger. First trickel method and second is boost method.
Total supply by the batteries = (voltage of each battery)* (number
of betteries)
= 2.2*55
= 121 volts
4.2 Transformer
Here step down of transformer is used for the supply in the workshop and further distribution
pupose. (750 KV to 433 KV)
A transformer is an electrical device that transfers electrical energy between two or more circuits
through electromagnetic induction. Electromagnetic induction produces an electromotive force
within a conductor which is exposed to time varying magnetic fields. Transformers are used to
increase or decrease the alternating voltages in electric power applications. It requires less
Fig 4.4 battery charger
Fig 4.5 batteries connected in
series

15. 15
maintenance then other equipments.
4.3 Distribution room
It consists of capacitor bank, bus bars, changeover switch (switch to generator), main switch etc.
Power factor should not raise up to a limit so capacitor banks are installed, in case if generator
(440KV) is used for the supply to load then capacitor bank is not required, power factor of
generator is already 0.8 in case capacitor bank may burn the generator due to overload
condition.
Fig 4.6 Transformer
Fig 4.7 capacitor bank

16. 16
CAPACITORS are electrical/electronic components which store electrical energy. Capacitors
consist of two conductors that are separated by an insulating material or dielectric. When an
electrical current is passed through the conductor pair, a static electric field develops in the
dielectric which represents the stored energy. Unlike batteries, this stored energy is not
maintained indefinitely, as the dielectric allows for a certain amount of current leakage which
results in the gradual dissipation of the stored energy. Power factor is defined as the difference in
phase between voltage and current, or simplified as the ratio of the real power (P) and the
apparent power (S). People will often refer to power factor as leading or lagging.
Lagging power factor: when the current lags the voltage, this means that the current waveform
comes delayed after the voltage waveform (and the power angle is positive).
Leading power factor: when the current leads the voltage, this means that the current waveform
comes before the voltage waveform (and the power angle is negative).
Unity power factor: refers to the case when the current and voltage are in the same phase.
Neither lagging nor leading.
A power factor of one or "unity power factor" is the goal of any electric utility company since if
Fig 4.8 Main supply to load (bus bars)

17. 17
the power factor is less than one, they have to supply more current to the user for a given amount
of power use. In doing so, they incur more line losses. They also must have larger capacity
equipment in place than would be otherwise necessary. As a result, an industrial facility will be
charged a penalty if its power factor is much different from 1. In electrical power distribution, a
busbar is a metallic strip or bar (typically copper, brass or aluminum) that conducts electricity
within a switchboard, distribution board, substation, battery bank, or other electrical apparatus.
Its main purpose is to conduct a substantial current of electricity, and not to function as a
structural member. Busbars may or may not be enclosed in a bus duct. Also, bus bars are
important components in electrical power grid because they can reduce the power loss via
reducing the corona effects. This is because busbars have bigger surface areas compared to
wires.
4.4 MCB or MCCB – Difference in IEC Standards (IEC 60898-1 & IEC
60947-2)
Circuit breakers are installed and used for safety purposes in both residential as well as
commercial and industrial areas. In power distribution, we need circuit breakers at different
levels. Depending on the current carrying capacity, breaking capacity and other functions, we
select a suitable circuit breaker according to our needs i.e. VCB, ACB (Air Circuit Breaker),
MCCB and then MCB , this is common hierarchy being followed in power distribution system.
Fig 4.9 Voltmeter and ammeter Fig 4.10 main supply switch

18. 18
MCB or MCCB - Difference in IEC Standards - IEC 60898-1 & IEC 60947-2
4.4.1 What is MCB?
MCB: MCB stands for “Miniature Circuit Breaker”. Rated current under 100 amps.
Interrupting rating of under 18,000 amps Trip characteristics may not be adjusted Suitable for
low current circuits (low energy requirement), i.e. home wiring. Generally, used where normal
current is less than 100 Amps. Generally, used where normal current is more than 100 Amps.
4.4.2 What is MCCB?
MCCB: MCBB stands for “Molded Case Circuit Breaker”. Rated current in the range of 10-2500
amps. Thermal operated for overload and & Magnetic operation for instant trip in SC (Short
circuit conditions) Interrupting rating can be around 10k – 200k amps. Suitable for high power
rating and high-energy i.e. commercial and industrial use. Generally, used where normal current
is more than 100 Amps.
4.4.3 Should I go for MCB or MCCB?
Now the question is that for a situation, where standard current
carrying capacity needed is 100A with breaking capacity of 15KA,
what should be used? An MCB or an MCCB? We assume cost is
not very different. Both are in moulded case and having almost
similar features especially when we are comparing with fixed
thermal setting option of MCCB and they are classified as low
voltage circuit breakers. For magnetic setting, we can select MCB
as per curve and MCCB will have either fixed setting or can be
adjusted.
So what is the criterion to make a selection of MCB or MCCB? Space can be a point of
consideration as MCBs are more compact but it doesn’t make a big point as bigger size of
MCCB brings many advantages too like better fault clearing mechanism. Keep in mind that both
MCB & MCCB are low voltage circuit breakers and created to respond to IEC 947 standards
Fig 4.11 MCCB

19. 19
(We are going to discuss these standards below) actually, there is difference in standards they
follows. An MCB is supposed to function in accordance to IEC 60898-1 (Unless mentioned
otherwise) and so is tested accordingly. While an MCCB is tested in accordance with IEC60947-
2. So to understand the difference between MCB and MCCB we need to get a brief idea of these
two standards.
4.4.4 ELCB
An Earth-leakage circuit breaker (ELCB) is a safety device used in
electrical installations with high Earth impedance to prevent shock.
It detects small stray voltages on the metal enclosures of electrical
equipment, and interrupts the circuit if a dangerous voltage is
detected.
Difference between ICS & ICU in term of Circuit Breakers.
ICS = Service Braking Capacity (means, Circuit breaker can remove the fault, but it may not be
usable afterwards.)
ICU = Ultimate Braking Capacity (means, Circuit breaker can remove the fault and remain
usable)
Fig 4.12 ELCB
Fig 4.13 MCB, MCCB and load busbars

20. 20
4.5 House wiring
4.5.1 Consumer unit:
Consumer Unit (CU)
The Consumer Unit, called a fuse box, contains these things:
1. A main isolating switch. This switches off everything.
2. In most cases at least one RCD
3. A fuse or MCB for each circuit.
4. This cuts the power to the circuit in the event of high fault current.
5. An earth connection block which connects earth to the earth wires of the various circuit
6. 1 or 2 neutral connection blocks which supply the neutral connection to the Neutral wires of
the various circuits
Each fuse or MCB supplies one circuit only. One circuit may supply anything from 1 to a large
number of loads.
4.5.2 Earthing:
Earthing is a fundamental safety system used in electrical installations. It works in co-ordination
with circuit breakers MCBs, Fuses, and RCDs to ensure that an electrical supply can be
disconnected quickly in the event of a fault. This greatly reduces shock risk.
Fig 4.13 house circuit diagram

21. 21
Most houses have an earth connection supplied by the electricity supplier. Those that don't
(generally country houses several miles from the nearest town), use a local earth rod instead.
The supplier's earthing terminal or your own earth rod is connected to the CU earth block. Each
electrical circuit in the house takes its earth connection from the CU earthing block.
4.5.3 Residual Current Devices (RCD)
The 17th Edition of the wiring regulations imposes more frequent requirements to install RCD
(or RCBO) protection than the previous 16th Edition. In general, ANY cable which is buried less
than 50mm below a wall's surface AND is NOT mechanically protected, or wired in one of a
number of specialized cable types that incorporate an earthed screen must have 30mA trip RCD
protection. Such circuit protection may be derived from either an RCD protecting several
circuits, or individual RCD/RCBOs on each circuit.
New installations will have two or more RCDs. Older ones may only have one or none.
(Currently half the properties in the UK have none according to research)
RCDs reduce the risks of injury from electric shock (they don't eliminate it completely), however
they can also introduce reliability and issues of their own if not used in an appropriate way.
Historically RCDs were usually only used on some circuits rather than all.
With a supplier provided earth connection, the most common historical arrangement was a split
CU with a RCD on one side, and no RCD on the other. Generally the RCD side is used to supply
sockets and shower, with most other items on the non-RCD side.
With a local earth rod, the situation is different in that all circuits must be RCD protected, since a
local earth rod is not usually a sufficiently good earth on its own to clear all earth faults. So
RCDs are used on all circuits even in older installations. A common option is to have the supply
fed through a 100mA time delayed RCD, the output of which goes to a split CU with RCD on
one side. This is not an ideal arrangement, as a large earth leakage fault on the non-RCD side
will cause complete power failure, and sometimes inability to reset the power.
4.5.4 RCBOs
An RCBO is a combined RCD and MCB in one module, and is fitted in place of an MCB.
RCBOs allow individual circuits to be protected by their own RCD without any risk that a fault
in an unrelated circuit could cause it to trip. However protecting all circuits like this is more
expensive.
Where RCBOs are used, they are fitted in the non-RCD side of the CU, and supply circuits
needing RCD protection. See 17th Edition Consumer Units for details.
4.5.5 Cable Color changes
Although the UK has used the European standard of Blue / Brown coloring for flexes for a long
time, the same color standard has also now been adopted for fixed wiring as well. Hence you
need to be aware of the changes:

22. 22
1. Old colors:
Red = Live
Black = Neutral
Bare or green/yellow = Earth
2. New Colors:
Brown = Live
Blue = Neutral
Bare or green/yellow = Earth

23. 23
Chapter 5
INSTRUMENTS USED
5.1 For Checking Lumens:
Called as luxmeter, Lumens should be check in a particular level for
every light in the room.
What is a lumen of light?
Watts measure the amount of energy required to light products,
whereas lumens measure the amount of light produced. The more
lumens in a light bulb, the brighter the light. With new light bulbs,
shopping by lumens will be more important than shopping by watts
when choosing which energy-efficient bulb to purchase
5.2 Tachometer
It’s a meter having quality of analysis the speed of moving induction
motor. It’s having one side lock button to set our required range
speed and one side having push button for on the meter. In the small
scale the range is (0-100-200-1000) and for the large scale the range
is (0-1000-5000)
5.3 Clamp meter
It is the gadget having the quality for checking the voltage, current,
resistance, and power simultaneously as per requirement. But the
main disadvantage is we can check the voltage by the wires
connected with on common and another voltage. And there is coil in
the meter which generates the magnetic field by which it can check
the electrical parameter.
Fig 5.1 Luxmeter
Fig 5.2 tachometer
Fig 5.3 clamp meter

24. 24
5.4 Insulation Resistance Tester
Insulation resistance tester having an inbuilt generator to
produce voltage. If we touch the terminals and move the handle
then we get shock and not to move fatly otherwise high
shock400-500 V cause death.
5.5 Timer
A timer is a specialized type of clock for measuring time
intervals. By function timers can be categorized to two main
types. A timer which counts upwards from zero for measuring
elapsed time is often called a stopwatch; a device which counts
down from a specified time interval is more usually called a timer
or a countdown timer
Fig 5.4 insulation resistance
tester
Fig 5.5 Timer

25. 25
Chapter 6
VISIT TO RIG
Main points:
1. 24 hours working
2. Engineers required: Mechanical, Electrical and included many other branches.
3. Rigs established for 6 months (may stretched for 1 year)
4. For excretion of crude oil and natural gas
5. Rigs locators are used
Visit to rig:
Fig 6.1 diagram of rig

26. 26
1. Crown block
An assembly of sheaves or pulleys
mounted on beams at the top of the
derrick. The drilling line is run over the
sheaves down to the hoisting drum.
2. Hoist line
A structural framework erected near the
top of the derrick for lifting material.
3. Drilling line
A wire rope hoisting line, revved on
sheaves of the crown block and traveling
block (in effect a block and tackle). Its
primary purpose is to hoist or lower drill
pipe or casing from or into a well. Also, a
wire rope used to support the drilling
tools.
4. Monkey board
The derrick man’s working platform.
Double board, tribble board, fourable
board; a monkey board located at a height
in the derrick or mast equal to two, three,
or four lengths of pipe respectively
5. Travelling block
An arrangement of pulleys or sheaves through which drilling cable is revved, which moves up or
down in the derrick or mast.
Fig 6.2 construction of rig

27. 27
6. Top drive
The top drive rotates the drill string end bit without the use of a kelly and rotary table. The top
drive is operated from a control console on the rig floor
7. Mast
A portable derrick capable of being erected as a unit, as distinguished from a standard derrick,
which cannot be raised to a working position as a unit.
8. Drill pipe
The heavy seamless tubing used to rotate the bit and circulate the drilling fluid. Joints of pipe 30
feet long are coupled together with tool joints
9. Doghouse
A small enclosure on the rig floor used as an office for the driller or as a storehouse for small
objects. Also, any small building used as an office or for storage.
10. Blowout preventer
One or more valves installed at the wellhead to prevent the escape of pressure either in the
annular space between the casing and the drill pipe or in open hole (for example, hole with no
drill pipe) during drilling or completion operations. See annular blowout preventer and ram
blowout preventer
11. Water tank
Is used to store water that is used for mud mixing, cementing, and rig cleaning
12. Electric cable tray
Supports the heavy electrical cables that feed the power from the control panel to the rig motors.
13. Engine generator set
A diesel, Liquefied Petroleum Gas (LPG), natural gas, or gasoline engine, along with a

28. 28
mechanical transmission and generator for producing power for the drilling rig. Newer rigs use
electric generators to power electric motors on the other parts of the rig
14. Fuel tanks
Fuel storage tanks for the power generating system.
15. Electric control house
On diesel electric rigs, powerful diesel engines drive large electric generators. The generators
produce electricity that flows through cables to electric switches and control equipment enclosed
in a control cabinet or panel. Electricity is fed to electric motors via the panel.
16. Mud pump
A large reciprocating pump used to circulate the mud (drilling fluid) on a drilling rig
17. Bulk mud components storage
Hopper type tanks for storage of drilling fluid components.
18. Mud pits
A series of open tanks usually made of steel plates, through which the drilling mud is cycled to
allow sand and sediments to settle out. Additives are mixed with the mud in the pit, and the fluid
is temporarily stored there before being pumped back into the well. Mud pit compartments are
also called shaker pits, settling pits, and suction pits, depending on their main purpose.
19. Reserve pits
A mud pit in which a supply of drilling fluid has been stored. Also, a waste pit, usually an
excavated, earthen-walled pit. It may be lined with plastic to prevent soil contamination
20. Mud gas separator
A device that removes gas from the mud coming out of a well when a kick is being circulated out
21. Shale shaker

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Series of trays with sieves or screens that vibrate to remove cuttings from circulating fluid in
rotary drilling operations. The size of the openings in the sieve is selected to match the size of
the solids in the drilling fluid and the anticipated size of cuttings. Also called a shaker.
22. Choke manifold
The arrangement special valves, called chokes, through which drilling mud is circulated when
the blowout preventers are closed to control the pressures encountered during a kick
23. Pipe ramp
Angled ramp for dragging drill pipe up to the drilling platform or bringing pipe down off the drill
platform.
24. Pipe racks
A horizontal support for tubular goods.
25. Accumulators
The storage device for nitrogen pressurized hydraulic fluid, which is used in operating the
blowout preventers.
Fig 6.3 visit to rig

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Chapter 7
SAFETY MEASURES
The human body conducts electricity. If any part of the body receives an electric shock, the
electricity will flow through the tissues with little obstruction. Depending on the length and
severity of the shock, injuries can include:
1. Burns to the skin
2. Burns to internal tissues
3. Electrical interference or damage (or both) to the heart, which could cause the heart to stop or
beat erratically.
Always disconnect the power supply before trying to help a victim of electric shock. Symptoms
of electric shock
The typical symptoms of an electric shock include:
1. Unconsciousness
2. Difficulties in breathing or no breathing at all.
3. A weak, erratic pulse or no pulse at all Burns, particularly entrance and exit burns (where the
electricity entered and left the body) Sudden onset of cardiac arrest Sometimes victims of electric
shock may appear to be unhurt, but they should still be treated as a victim of electric shock.
Some injuries and further complications may not yet be obvious. An examination in hospital is
important after any electric shock.
Causes of electric shock
1. Some of the causes of electric shock include:
2. Faulty appliances
3. Damaged or frayed cords or extension leads

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4. Electrical appliances coming in contact with water
5. Incorrect or deteriorated household wiring
6. Downed power lines
7. Lightning strike.
How to help a victim of electric shock
The first thing you must do is disconnect the power supply. Don’t even touch the victim until
you are sure that the power supply is turned off. Be especially careful in wet areas, such as
bathrooms, as water conducts electricity. It may be safer to turn off the electricity supply to the
building if possible to be absolutely sure.
First aid for electrical shock includes:
1. Check for a person’s response and breathing. It may be necessary to commence
cardiopulmonary resuscitation (CPR).
2. Call triples zero (000) for an ambulance.
3. If you are unsure of resuscitation techniques, the ambulance call-taker will give you easy-to-
follow instructions over the telephone, so you can increase the person’s chances of survival
until the ambulance arrives.
4. If their breathing is steady and they are responsive, attend to their injuries. Cool the burns
with cool running water for 20minutes and cover with dressings, if available, that won’t
stick. Simple cling wrap found in most kitchens is very suitable to cover burns as long as it is
not applied tightly.
5. Never put ointments or oils onto burns.
6. If the person has fallen from a height, try not to move them unnecessarily in case they have
spinal injuries. Only move them if there is a chance of further danger from the environment
(such as falling objects).
7. Talk calmly and reassuringly to the person.

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CONCLUSION
I have got practical knowledge of machines, lots of knowledge about so many things related to
my stream such as electrical knowledge as well as machines knowledge. To work with the
experienced engineers and respected seniors was a great experience.
The matter I have included in the file are the things I have learned in my training time period but
beyond this I have seen so many things such as repairing of machines, testing and connections of
motors, repairing of starters, repairing of lights, etc.
Heater Theater is manufacturing of ONGC Company itself.
There were so many GGS offices interconnected to ONGC Company.
I express my gratitude to Mr. H.S. Sehgal (chief electrical engineer) & Mr. A.B. Dave Sir, I am
very thankful to employees of ONGC. They guide me step by step with supportive nature.
I’d visited mechanical rig which is normally called as drilling rig, established for extraction of
crude oil and natural gas.
Overall, it was very good experience to work with experienced engineers and my colleagues.
.