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

1

Fig 1.1 logo of company

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

2

Fig 1.2 Ahmedabad asset, Sabarmati

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

3

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.

4

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:

1. Cranes

5

Fig 3.1 motor under

maintenance

Fig 3.2 motor under repair Fig 3.3 300hp motor

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.

3.4 Welding transformers

6

Fig 3.4 hoist (2 tones crane)

Fig 3.5 Autotransformer

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:

It is the equipment by which we can charge the batteries of the

vehicles, electrical machines etc. it have two meters first is

7

Fig 3.6 dry welding transformer Fig 3.7 oil welding transformer

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.

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

8

Fig 3.9 oil test machine

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

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

9

Fig 3.10 delcoremy type starter Fig 3.11 pinion

Fig 3.12 dimmer

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.

3.11 Induction Heater for Bearing

10

Fig 3.13 air compressor

Fig 3.14 fan rewinding machine

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)

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

11

Fig 3.15 induction heater for bearing

Fig 3.16 fan rewinding machine

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

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.

12

Fig 4.1 supply from torrent power

limited

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

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

13

Fig 4.2 HT meter

Fig 4.3 VCB

Fig 4.4 battery charger

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

maintenance then other equipments.

14

Fig 4.5 batteries connected in

series

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.

15

Fig 4.6 Transformer

Fig 4.7 capacitor bank

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

16

Fig 4.8 Main supply to load (bus bars)

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.

17

Fig 4.9 Voltmeter and ammeter Fig 4.10 main supply switch

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

18

Fig 4.11 MCCB

(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)

19

Fig 4.12 ELCB

Fig 4.13 MCB, MCCB and load busbars

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 RCD3. 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 circuit6. 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.

20

Fig 4.13 house circuit diagram

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:

21

1. Old colors:

Red = Live

Black = Neutral

Bare or green/yellow = Earth

2. New Colors:

Brown = Live

Blue = Neutral

Bare or green/yellow = Earth

22

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.

23

Fig 5.1 Luxmeter

Fig 5.2 tachometer

Fig 5.3 clamp meter

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

24

Fig 5.4 insulation resistance

tester

Fig 5.5 Timer

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:

25

Fig 6.1 diagram of rig

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.

26

Fig 6.2 construction of rig

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

27

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

28

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.

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Fig 6.3 visit to rig

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.

.

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