CONTENTS

1.0 OIL AND NATURAL GAS CORPORATION

2.0 ABOUT THE RIG

3.0 LIST OF COMPONENTS OF OIL DRILLING

4.0 DESCRIPTION OF VARIOUS MECHANICAL COMPONENTS

5.0 MUD CLEANING UNIT

6.0 HOW A WELL IS DRILLED ON LAND

OIL AND NATURAL GAS CORPORATION

INTRODUCTION Oil and Natural Gas Corporation Limited (ONGC) (incorporated on June 23, 1993) is an Indian

public sector petroleum company. It is a Fortune Global 500 company ranked 335th, and contributes 77%

of India's crude oil production and 81% of India's natural gas production. It is the highest profit making

corporation in India. It was set up as a commission on August 14, 1956. Indian government holds 74.14%

equity stake in this company.

ONGC is one of Asia's largest and most active companies involved in exploration and production of oil. It

is involved in exploring for and exploiting hydrocarbons in 26 sedimentary basins of India. It produces

about 30% of India's crude oil requirement. It owns and operates more than 11,000 kilometers of

pipelines in India. Until recently (March 2007) it was the largest company in terms of market cap in India.

FOUNDATION: In August 1956, the Oil and Natural Gas Commission was formed. Raised from mere Directorate status to

Commission, it had enhanced powers. In 1959, these powers were further enhanced by converting the

commission into a statutory body by an act of Indian Parliament.

1960-1990 Since its foundation stone was laid, ONGC is transforming India’s view towards Oil and Natural Gas by

emulating the country’s limited upstream capabilities into a large viable playing field. ONGC, since 1959,

has made its presence noted in most parts of India and in overseas territories. ONGC found new resources

in Assam and also established the new oil province in Cambay basin (Gujarat). In 1970 with the

discovery of Bombay High (now known as Mumbai High), ONGC went offshore. With this discovery

and subsequent discovery of huge oil fields in the Western offshore, a total of 5 billion tonnes of

hydrocarbon present in the country was discovered. The most important contribution of ONGC, however,

is its self-reliance and development of core competence in exploration and production activities at a

globally competitive level.

Post-1990 Post 1990, the liberalized economic policy was brought into effect; subsequently partial disinvestments of

government equity in Public Sector Undertakings were sought. As a result, ONGC was re-organized as a

limited company and after conversion of business of the erstwhile Oil & Natural Gas Commission to that

of Oil and Natural Gas Corporation Ltd in 1993, 2 percent of shares through competitive bidding were

disinvested. Further expansion of equity was done by 2 percent share offering to ONGC employees.

Another big leap was taken in March 1999, when ONGC, Indian Oil Corporation (IOC) and Gas

Authority of India Ltd. (GAIL) agreed to have cross holding in each other’s stock. Consequently the

Government sold off 10 per cent of its share holding in ONGC to IOC and 2.5 per cent to GAIL. With

this, the Government holding in ONGC came down to 84.11 per cent. In 2002-03 ONGC took over

Mangalore Refinery and Petrochemicals Limited (MRPL) from Birla Group and announced its entrance

into retailing business. ONGC also went to global fields through its subsidiary, ONGC Videsh Ltd.

(OVL). ONGC has made major investments in Vietnam, Sakhalin and Sudan and earned its first

hydrocarbon revenue from its investment in Vietnam. In 2009, ONGC discovered a massive oil field,

with up to 1 billion barrel reserves of heavy crude, in the Persian Gulf off the coast of Iran. Additionally,

ONGC also signed a deal with Iran to invest US$3 billion to extract 1.1 billion cubic feet of natural gas

from the Farzad B gas field.

INTERNATIONAL RANKING

ONGC has been ranked at 198 by the Forbes Magazine in their Forbes Global 2000 list for

the year 2007.

ONGC has featured in the 2008 list of Fortune Global 500 companies at position 335, a climb

of 34 positions from rank of 369 in 2007.

ONGC is ranked as Asia’s best Oil & Gas Company, as per a recent survey conducted by

US-based magazine ‘Global Finance’.

2nd biggest E&P company (and 1st in terms of profits), as per the Platts Energy Business

Technology (EBT) Survey 2004

Ranks 24th among Global Energy Companies by Market Capitalization in PFC Energy 50

(December 2004).

Economic Times 500, Business Today 500, Business Baron 500 and Business Week

recognized ONGC as most valuable Indian corporate, by Market Capitalization, Net Worth

and Net Profits.

LIST OF COMPONENTS OF OIL DRILLING

LIST OF ITEMS

1. Mud tank

2. Shale shakers

3. Suction line (mud pump)

4. Mud pump

5. Motor or power source

6. Vibrating hose

7. Draw-works

8. Standpipe

9. Kelly hose

10. Goose-neck

11. Traveling block

12. Drill line

13. Crown block

14. Derrick

15. Monkey board

16. Stand (of drill pipe)

17. Pipe rack (floor)

18. Swivel (On newer rigs this may be replaced by a top drive)

19. Kelly drive

20. Rotary table

21. Drill floor

22. Bell nipple

23. Blowout preventer (BOP) Annular type

24. Blowout preventer (BOP) Pipe ram & blind ram

25. Drill string

26. Drill bit

27. Casing head or Wellhead

28. Flow line

DESCRIPTION OF VARIOUS MECHANICAL COMPONENTS

1. MUD TANK

A mud tank is an open-top container, typically made of square steel tube and steel plate, to store drilling

fluid on a drilling rig. They are also called mud pits, because they used to be nothing more than pits dug

out of the earth.

Mud tanks play an important role in solids control system. It is the base of solids control equipments, and

also the carrier of drilling fluids. Solids control equipments that are all mounted on the top of mud tanks

include the followings:

Shale Shaker

Vacuum Degasser

Desander

Desilter

Centrifuge

Mud Agitator

Vertical slurry pump

Drilling fluids flow into the shale shaker directly after it returns to the surface of the well, and the solids

that are removed by the screen would be discharged out of the tank, and the drilling fluids with smaller

solids would flow through the screen into mud tank for further purification. A centrifugal pump would

suck the shaker-treated fluids up to the desilter or mud cleaner for further purification. And vertical slurry

pump is used to pump the drilling fluids up to the centrifuge, and mud pump would pump the drilling

fluids from mud tank into the borehole after it is treated by centrifuge. And the circulation system would

continue.

The number of the mud tanks that are needed on the drilling rig depends on the depth of the well, and also

the mud demands of drilling. Normally the shale shaker and vacuum degasser and desander are mounted

together on the same mud tank as the first tank at the oilfield, while desilter and centrifuge on the second

tank. Also the drilling rig has other different tank as reserve tank, emergency tank, etc.

Mud tank is an important part in the solids control system. Based on functions, mud tank includes:- Trip tank

Settling tank

Suction tank

Intermediate tank

Reserve tank

2. MUD PUMP

A mud pump is a reciprocating piston/plunger device designed to circulate drilling fluid under high

pressure (up to 7,500 psi (52,000 kPa)) down the drill

string and back up the annulus.

It can be classified as follows:-

According to the acting type

Mud Pumps can be divided into single-acting pump

and double-acting pump according to the completion

times of the suction and drainage acting in one cycle

of the piston's reciprocating motion

According to the quantity of liners (piston/plunger)

Mud Pumps come in a variety of sizes and configurations but for the typical petroleum drilling rig, the

triplex (three piston/plunger) Mud Pump is the pump of choice. Duplex Mud Pumps (two piston/plungers)

have generally been replaced by the triplex pump, but are still common in developing countries. Two later

developments are the hex pump with six vertical pistons/plungers, and various quintuplex's with five

horizontal piston/plungers. The advantages that these new pumps have over convention triplex pumps is a

lower mud noise which assists with better MWD and LWD retrieval.

The "normal" Mud Pump consists of two main sub-assemblies, the fluid end and the power end.

Fluid End: - The fluid end produces the pumping process with valves, pistons, and liners. Because these

components are high-wear items, modern pumps are designed to allow quick replacement of these parts.

To reduce severe vibration caused by the pumping process, these pumps incorporate both a suction and

discharge pulsation dampener. These are connected to the inlet and outlet of the fluid end.

Power End:-The power end converts the rotation of the drive shaft to the reciprocating motion of the

pistons. In most cases a crosshead crank gear is used for this.

Mud Pump Parts

A Mud Pump is composed of many parts including Mud Pump liner, Mud Pump piston, modules,

hydraulic seat pullers, and other parts.

Parts of Mud Pump: 1.Piston rod, 2.Connecting rod, 3.Piston extension rod, 4.Piston and Liner (61/2”

&

51/2”

), 5.Suction valve and Discharge valve with their seats, 6.Oil filter, 7.Magnetic filter, 8.Oil cooler,

9.Safety valve, 10. Pulsation dampener, 11.Compensating balloon, 12.Chains, 13.Wear plate, 14.Flushing

Pump, 15.Rubber bushing.

3. DRAW WORKS A draw-works is the primary hoisting machinery that is a component of a rotary drilling rig. Its main

function is to provide a means of raising and lowering the traveling blocks. The wire-rope drilling line

winds on the draw works drum and extends to the crown block and traveling blocks, allowing the drill

string to be moved up and down as the drum turns. The segment of drilling line from the draw-works to

the crown block is called the "fast line". The drilling line then enters the sheaves of the crown block and

is makes several passes between the crown block and traveling block pulleys for mechanical advantage.

The line then exits the last sheave on the crown block and is fastened to a derrick leg on the other side of

the rig floor. This section of drilling line is called the "dead line". A modern draw-works consists of five main parts: the drum, the motor(s), the reduction gear, the brake,

and the auxiliary brake. The motors can be AC or DC-motors, or the draw-works may be connected

directly to diesel engines using metal chain-like belts. The number of gears could be one, two or three

speed combinations. The main brake, usually operated manually by a long handle, may be friction band

brake, a disc brake or a modified clutch. It serves as a parking brake when no motion is desired. The

auxiliary brake is connected to the drum, and absorbs the energy released as heavy loads are lowered.

This brake may use eddy current rotors or water turbine- like apparatus to convert to heat the kinetic

energy of a downward-moving load being stopped.

Power catheads (winches) located on each side provide the means of actuating the tongs used to couple

and uncouple threaded pipe members. Outboard catheads can be used manually with ropes for various

small hoisting jobs around the rig.

The draw-works often has a pulley drive arrangement on the front side to provide turning power to the

rotary table, although on many rigs the rotary table is independently powered.

4. ROTARY TABLE (DRILLING RIG)

A rotary table is a mechanical device on a drilling rig

that provides clockwise (as viewed from above)

rotational force to the drill string to facilitate the process

of drilling a borehole. Rotary speed is the number of

times the rotary table makes one full revolution in one

minute (rpm).

Most rotary tables are chain driven. These chains resemble very large bicycle chains. The chains require

constant oiling to prevent burning and seizing. Virtually all rotary tables are equipped with a rotary lock'.

Engaging the lock can either prevent the rotary from turning in one particular direction, or from turning at

all. This is commonly used by crews in lieu of using a second pair of tongs to makeup or break out pipe.

The rotary bushings are located at the center of the rotary table. These can generally be removed in two

separate pieces to facilitate large items, i.e. drill bits, to pass through the rotary table. The large gap in the

center of the rotary bushings is referred to as the "bowl" due to its appearance. The bowl is where the

slips are set to hold up the drill string during connections and pipe trips as well as the point the drill string

passes through the floor into the wellbore. The rotary bushings connect to the kelly bushings to actually

induce the spin required for drilling.

5. DRILLING MUD CENTRIFUGAL PUMP

Centrifugal pumps are a sub-class of dynamic axis symmetric work absorbing turbo machinery. Centrifugal pumps are used to transport fluids by the conversion of rotational kinetic energy to the

hydrodynamic energy of the fluid flow. The rotational energy typically comes from an engine or electric

motor. The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the

impeller, flowing radially outward into a diffuser or volute chamber (casing), from where it exits.

Common uses include water, sewage, petroleum and petrochemical pumping. The reverse function of the

centrifugal pump is a water turbine converting potential energy of water pressure into mechanical

rotational energy.

Applications of Drilling Mud Centrifugal Pump: - Drilling mud centrifugal pump is used for transporting

drilling fluids. It can be used as oilfield drilling feeding centrifugal pump for drilling mud desander,

drilling fluids desilter, or used as mixing pump for jet mud mixer. Also it can be used as trip pump and

supercharging pump for drilling rig mud pump.

Parts of Centrifugal Pump: - 1.Casing (6” *8” *14”), 2.Impeller, 3.Shaft, 4.Wear plate, 5.Vane,

6.Discharge Nozzle, 7.Bearing Housing

6. STAND (DRILL PIPE)

A stand (of drill pipe) is two or three joints of drill pipe

connected and stood in the derrick vertically, usually while

tripping pipe. A stand of collars is similar, only made up of

collars and a collar head. The collar head is screwed into

the collar to allow it to be picked up by the elevators.

Stands are emplaced inside of the "board" of the drilling

rig. They are usually kept between "fingers". Most boards

will allow stands to go ten stands deep and as much as fifty

stands wide on land based rigs. The stands are further held

in place using ropes in the board which are tied in a shoe

knot by the derrickman.

Stands are emplaced on the floor of the drilling rig by the

chain hand. When stands are being put onto the floor the

chainhand is said to be "racking stands". After the bottom

of the stand is placed on the floor, the derrickman will unlatch the elevators and pull the stand in either

with a rope or with just his arms. When stands are being put back into the hole, the derickman will slam

the stand into the elevators to force them to latch. The chainhand will brace against the stand to control it

when the driller picks it up. This is referred to as "tailing the pipe" as the chain hand will hold the pipe

and allow it to semi-drag them back to the hole. The chain hand then passes it off to the tong hand, which

then "stabs" the stand into the pipe already in the hole.

Rigs are generally sized by how many stands they can hold in their derrick. Most land based rigs are

referred to as "triples" because they hold three joints per stand in their derrick. "Singles" generally do not

hold any pipe in the derrick and instead require pipe to be laid down during a pipe trip.

7. SWIVEL (DRIL RIG)

A Swivel is a mechanical device used on a drilling rig that hangs

directly under the traveling block and directly above the kelly

drive, that provides the ability for the kelly (and subsequently the

drill string) to rotate while allowing the traveling block to remain

in a stationary rotational position (yet allow vertical movement up

and down the derrick) while simultaneously allowing the

introduction of drilling fluid into the drill string.

8. MOTOR

An electric motor is an electric machine that converts electrical energy into mechanical energy. In normal

motoring mode, most electric motors operate through the interaction between an electric motor's magnetic

field and winding currents to generate force within the

motor. In certain applications, such as in the

transportation industry with traction motors, electric

motors can operate in both motoring and generating or

braking modes to also produce electrical energy from

mechanical energy.

Found in applications as diverse as industrial fans,

blowers and pumps, machine tools, household

appliances, power tools, and disk drives, electric motors

can be powered by direct current (DC) sources, such as

from batteries, motor vehicles or rectifiers, or

by alternating current (AC) sources, such as from the

power grid, inverters or generators. Small motors may be

found in electric watches. General-purpose motors with highly standardized dimensions and

characteristics provide convenient mechanical power for industrial use. The largest of electric motors are

used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching

100 megawatts. Electric motors may be classified by electric power source type, internal construction,

application, type of motion output, and so on.

Devices such as magnetic solenoids and loudspeakers that convert electricity into motion but do not

generate usable mechanical power are respectively referred to as actuators and transducers. Electric

motors are used to produce linear force or torque (rotary).

9. BLOW OUT PREVENTER

A blowout preventer is a large, specialized valve

or similar mechanical device, usually installed

redundantly in stacks, used to seal, control and

monitor oil and gas wells. Blowout preventers

were developed to cope with extreme erratic

pressures and uncontrolled flow (formation kick)

emanating from a well reservoir during drilling.

Kicks can lead to a potentially catastrophic event

known as a blowout. In addition to controlling

the downhole (occurring in the drilled hole)

pressure and the flow of oil and gas, blowout

preventers are intended to prevent tubing (e.g.

drill pipe and well casing), tools and drilling

fluid from being blown out of the wellbore (also known as bore hole, the hole leading to the

reservoir) when a blowout threatens. Blowout preventers

are critical to the safety of crew, rig (the equipment

system used to drill a wellbore) and environment, and to

the monitoring and maintenance of well integrity; thus

blowout preventers are intended to provide fail safety to

the systems that include them.

The term BOP (pronounced B-O-P, not "bop") is used in

oilfield vernacular to refer to blowout preventers. The

abbreviated term preventer, usually prefaced by a type

(e.g. ram preventer), is used to refer to a single blowout

preventer unit. A blowout preventer may also simply be

referred to by its type (e.g. ram).

The terms blowout preventer, blowout preventer stack

and blowout preventer system are commonly used

interchangeably and in a general manner to describe an

assembly of several stacked blowout preventers of

varying type and function, as well as auxiliary

components. A typical subsea deepwater blowout

preventer system includes components such as electrical and hydraulic lines, control pods, hydraulic

accumulators, test valve, kill and choke lines and valves, riser joint, hydraulic connectors, and a support

frame.

Two categories of blowout preventer are most prevalent: ram and annular. BOP stacks frequently utilize

both types, typically with at least one annular BOP stacked above several ram BOPs.

Blowout preventers are used at land and oil platform offshore rigs, and subsea. Land and subsea BOPs are

secured to the top of the wellbore, known as the wellhead. BOPs on offshore rigs are mounted below the

rigdeck.

10. CROWN BLOCK A crown block is the stationary section of a block and tackle that

contains a set of pulleys or sheaves through which the drill line (wire

rope) is threaded or reeved and is opposite and above the traveling

block.

The combination of the traveling block, crown block and wire rope

drill line gives the ability to lift weights in the hundreds of thousands

of pounds. On larger drilling rigs, when raising and lowering the

derrick, line tensions over a million pounds are not unusual.

11. DRILL BIT

A Drill bit is a device attached to the end of the

drill string that breaks apart, cuts or crushes the

rock formations when drilling a wellbore, such as

those drilled to extract water, gas, or oil.

The drill bit is hollow and has jets to allow for the expulsion of the drilling fluid, or "mud", at high

velocity and high pressure to help clean the bit and, for softer formations, help to break apart the rock. A

tricone bit comprises three conical rollers with teeth made of a hard material, such as tungsten carbide.

The teeth break rock by crushing as the rollers move around the bottom of the borehole. A polycrystalline

diamond compact (PDC) bit has no moving parts and works by scraping the rock surface with disk-

shaped teeth made of a slug of synthetic diamond attached to a tungsten carbide cylinder.

12. DRILL STRING

A drill string on a drilling rig is a column, or string, of drill pipe that transmits drilling fluid (via the mud

pumps) and torque (via the kelly drive or top drive) to the drill bit. The term is loosely applied as the

assembled collection of the drill pipe, drill collars, tools and drill bit. The drill string is hollow so that

drilling fluid can be pumped down through it and circulated back up the annulus (the void between the

drill string and the casing/open hole).

Drill string components

The drill string is typically made up of three sections:

Bottom hole assembly (BHA)

Transition pipe, which is often heavyweight drill pipe (HWDP)

Drill pipe

Bottom hole assembly (BHA):-The BHA is made up of: a drill bit, which is used to break up the rock

formations; drill collars, which are heavy, thick-walled tubes used to apply weight to the drill bit; and

drilling stabilizers, which keep the assembly centered in the hole. The BHA may also contain other

components such as a downhole motor and rotary steerable system, measurement while drilling (MWD),

and logging while drilling (LWD) tools. The components are joined together using rugged threaded

connections. Short "subs" are used to connect items with dissimilar threads.

Transition pipe :-Heavyweight drill pipe (HWDP) may be used to make the transition between the drill

collars and drill pipe. The function of the HWDP is to provide a flexible transition between the drill

collars and the drill pipe. This helps to reduce the number of fatigue failures seen directly above the BHA.

A secondary use of HWDP is to add additional weight to the drill bit. HWDP is most often used as weight

on bit in deviated wells. The HWDP may be directly above the collars in the angled section of the well, or

the HWDP may be found before the kick off point in a shallower section of the well.

Drill pipe:-Drill pipe makes up the majority of the drill string back up to the surface. Each drill pipe

comprises a long tubular section with a specified outside diameter (e.g. 3 1/2 inch, 4 inch, 5 inch, 5 1/2

inch, 5 7/8 inch, 6 5/8 inch). At the each end of the drill pipe tubular, larger-diameter portions called the

tool joints are located. One end of the drill pipe has a male ("pin") connection whilst the other has a

female ("box") connection. The tool joint connections are threaded which allows for the making of each

drill pipe segment to the next segment.

13. DRILL LINE

In a drilling rig, the drill line is a multi-thread, twisted wire rope that is threaded or reeved through

the traveling block and crown block to facilitate the lowering and lifting of the drill string into and out of

the wellbore.

On larger diameter lines, traveling block loads of over a million pounds are possible. To make a

connection is to add another segment of drill pipe onto the top the drill string. A segment is added by

pulling the kelly above the rotary table, stopping the mud pump, hanging off the drill string in the rotary

table, unscrewing the kelly from the drill pipe below, swinging the kelly over to permit connecting it to

the top of the new segment (which had been placed in the mousehole), and then screwing this assembly

into the top of the existing drill string. Mud circulation is resumed, and the drill string is lowered into the

hole until the bit takes weight at the bottom of the hole. Drilling then resumes.

14. DRILLING FLUID

In geotechnical engineering, drilling fluid is used to aid the drilling of boreholes into the earth. Often used

while drilling oil and natural gas wells and on exploration drilling rigs, drilling fluids are also used for

much simpler boreholes, such as water wells.

Liquid drilling fluid is often called drilling mud. The three main categories of drilling fluids are water-

based muds (which can be dispersed and non-dispersed), non-aqueous muds, usually called oil-based

mud, and gaseous drilling fluid, in which a wide range of gases can be used.

Functions : -

Remove cuttings from well

Suspend and release cuttings

Control formation pressures

Seal permeable formations

Maintain wellbore stability

Minimizing formation damage

Cool, lubricate, and support the bit and drilling assembly

Transmit hydraulic energy to tools and bit

Ensure adequate formation evaluation

Control corrosion (in acceptable level)

Facilitate cementing and completion

Minimize impact on environment

Three factors affecting drilling fluid performance are: -

The change of drilling fluid viscosity

The change of drilling fluid density

The change of mud Ph

15. KELLY DRIVE

A kelly drive refers to a type of well drilling device on an oil or gas drilling rig that employs a section of

pipe with a polygonal (three-, four-, six-, or eight-sided) or splined outer surface, which passes through

the matching polygonal or splined kelly (mating) bushing and rotary table. This bushing is rotated via the

rotary table and thus the pipe and the attached drill string turn while the polygonal pipe is free to slide

vertically in the bushing as the bit digs the well deeper. When drilling, the drill bit is attached at the end

of the drill string and thus the kelly drive provides the means to turn the bit (assuming that a downhole

motor is not being used).

The kelly is the polygonal tubing and the kelly bushing is the mechanical device that turns the kelly when

rotated by the rotary table. Together they are referred to as a kelly drive. The upper end of the kelly is

screwed into the swivel, using a left-hand thread to preclude loosening from the right-hand torque applied

below. The kelly typically is about 10 ft (3 m) longer than the drill pipe segments, thus leaving a portion

of newly drilled hole open below the bit after a new length of pipe has been added ("making a

connection") and the drill string has been lowered until the kelly bushing engages again in the rotary

table.

The kelly hose is the flexible, high-pressure hose connected from the standpipe to a gooseneck pipe on a

swivel above the kelly and allows the free vertical movement of the kelly while facilitating the flow of the

drilling fluid down the drill string. It generally is of steel-reinforced rubber construction but also

assemblies of Chiksan steel pipe and swivels are used.

The name kelly is derived from the machine shop in which the first kelly was made. It was located in a

town formerly named Kellysburg, Pennsylvania.

16. KELLY HOSE

A Kelly hose (also known as a mud hose or rotary hose) is a flexible, steel reinforced, high pressure hose

that connects the standpipe to the kelly (or more specifically to the goose-neck on the swivel above the

kelly) and allows free vertical movement of the kelly while facilitating the flow of drilling fluid through

the system and down the drill string.

17. PIPE RACK

Structural steel pipe racks typically support pipes, power cables and instrument cable trays in

petrochemical, chemical and power plants. Occasionally, pipe racks may also support mechanical

equipment, vessels and valve access platforms. Main pipe racks generally transfer material between

equipment and storage or utility areas.

Storage racks found in warehouses are not pipe racks, even if they store lengths of pipe.

A pipe rack is the main artery of a process unit. Pipe racks carry process and utility piping and may also

include instrument and cable trays as well as equipment mounted over all of these.

Pipe racks consist of a series of transverse bents that run along the length of the pipe system, spaced at

uniform intervals typically around 20 ft. To allow maintenance access under the pipe rack, the transverse

bents are typically moment frames. Transverse bents are typically connected with longitudinal struts.

18. RIG STANDPIPE

A rig standpipe is a solid metal pipe attached to the side of a drilling rig's derrick that is a part of its

drilling mud system. It is used to conduct drilling fluid from the mud pumps to the kelly hose. Bull plugs,

pressure transducers and valves are found on the rig standpipe.

19. TRAVELLING BLOCK

A traveling block is the freely moving section of a block and tackle that contains a set of pulleys or

sheaves through which the drill line (wire rope) is threaded or reeved and is opposite (and under) the

crown block (the stationary section). The combination of the traveling block, crown block and wire rope

drill line gives the ability to lift weights in the hundreds of thousands of pounds. On larger drilling rigs,

when raising and lowering the derrick, line tensions over a million pounds are not unusual.

20. FLOW LINE

A flow line, used on a drilling rig, is a large diameter pipe (typically a section of casing) that is connected

to the bell nipple (under the drill floor) and extends to the possum belly (on the mud tanks) and acts as a

return line, (for the drilling fluid as it comes out of the hole), to the mud tanks.

21. BELL NIPPLE

A Bell nipple is a section of large diameter pipe fitted to the top of the blowout preventers that the flow

line attaches to via a side outlet, to allow the drilling fluid to flow back over the shale shakers to the mud

tanks.

22. DRILL FLOOR

The Drill Floor is the heart of any drilling rig. This is the area

where the drill string begins its trip into the earth. It is

traditionally where joints of pipe are assembled, as well as the

BHA (bottom hole assembly), drilling bit, and various other tools.

This is the primary work location for roughnecks and the driller.

The drill floor is located directly under the derrick.

The floor is a relatively small work area in which the rig crew

conducts operations, usually adding or removing drill pipe to or

from the drill string. The rig floor is the most dangerous location

on the rig because heavy iron is moved around there. Drill string

connections are made or broken on the drill floor, and the driller's

console for controlling the major components of the rig are

located there. Attached to the rig floor is a small metal room, the

doghouse, where the rig crew can meet, take breaks and take

refuge from the elements during idle times.

23. MONKEY BOARD Monkey board is the catwalk along the side of the derrick (usually about 35 or 40 feet above the "floor").

The monkey board is where the derrick man works while "tripping" pipe.

24. GOOSE-NECK Goose-neck is a thick metal elbow connected to the swivel and standpipe that supports the weight of and

provides a downward angle for the kelly hose to hang from.

25. VIBRATING HOSE Vibrating hose is a flexible, high pressure hose (similar to the kelly

hose) that connects the mud pump to the stand pipe. It is called the

vibrating hose because it tends to vibrate and shake (sometimes

violently) due to its close proximity to the mud pumps.

26. AGITATOR An agitator is a device or mechanism to put something into motion by shaking or stirring. There are three

main types of agitation machines the washing machine agitator, which rotates back and forth; the

magnetic agitator, which contains a magnetic bar which rotates about a magnetic field; manual agitation,

such as with a stirring rod.

27. MUD MOTOR A mud motor (or drilling motor) is a progressive

cavity positive displacement pump (PCPD) placed in

the drill string to provide additional power to the bit

while drilling. The PCPD pump uses drilling

fluid (commonly referred to as drilling mud, or just

mud) to create eccentric motion in the power section

of the motor which is transferred as concentric power

to the drill bit (well). The mud motor uses different

rotor and stator configurations to provide optimum

performance for the desired drilling operation,

typically increasing the number of lobes and length of

power assembly for greater horsepower. In certain

applications, compressed air, or other gas, can be used

for mud motor input power. Normal rotation of the bit while using a mud motor can be from 60 rpm, to

over 100 rpm.

Basic principle :- Based on the principle developed by Rene Moineau, the theory states that a helical

rotor with one or more lobes will rotate eccentrically when the stator contains more lobes than the rotor.

The flow of the fluid transmits power allowing the assembly to rotate and turn the bit.

Advantages :- Extremely hard rock formations can be drilled with motors using diamond or PDC bits.

High penetration rates can be achieved since rotation speeds are high. Will allow circulation of the

borehole regardless of the horsepower or torque produced by the motor.

MUD CLEANING UNIT

1. SHALE SHAKER

Shale shakers are components of drilling equipment used in many industries, such as coal cleaning,

mining, oil and gas drilling. They are the first phase of a solids control system on a drilling rig, and are

used to remove large solids (cuttings) from the drilling fluid

("Mud").

Drilling fluids are integral to the drilling process and, among

other functions, serve to lubricate and cool the drill bit as

well as convey the drilled cuttings away from the bore hole.

These fluids are a mixture of various chemicals in water or

oil based solution and can be very expensive to make. For

both environmental reasons and to reduce the cost of drilling

operations, drilling fluid losses are minimized by stripping

them away from the drilled cuttings before the cuttings are

disposed of. This is done using a multitude of specialized

machines and tanks.

Shale shakers are the primary solids separation tool on a rig.

After returning to the surface of the well the used drilling fluid flows directly to the shale shakers where it

begins to be processed. Once processed by the shale shakers the drilling fluid is deposited into the mud

tanks where other solid control equipment begins to remove the finer solids from it. The solids removed

by the shale shaker are discharged out of the discharge port into a separate holding tank where they await

further treatment or disposal.

Shale shakers are considered by most of the drilling industry to be the most important device in the solid

control system as the performance of the successive equipment directly relates to the cleanliness of the

treated drilling fluid.

Mudloggers usually go out and check the shakers for rock samples that have circulated from bottom.

They separate the rock from the drilling fluid and take it into an onsite lab where they dry out the samples

and label them according to depth. They then look at the samples and analyze what kind of rock they have

at a certain depth. This helps determines what depth that type of rock was encountered.

2. DESANDER

Desanders are solid control equipment with a set of hydrocyclones that separate sand and silt from the

drilling fluids in drilling rigs. Desanders are installed on top of the mud tank following the shale shaker

and the degasser, but before the desilter. Desander removes the abrasive solids from the drilling fluids

which cannot be removed by shakers. Normally the solids diameter for desander to be separated would be

45~74μm, and 15~44μm for desilter.

A centrifugal pump is used to pump the drilling fluids from mud tank into the set of hydrocyclones.

Solids control Desanders have moving parts. The larger the internal diameter of the desander is, the greater the amount

of drilling fluids it is able to process and the larger the size of the solids removed. A desander with a (10

inches (250 mm) cone) is able to remove 50% of solids within the 40-50 μm (micrometer) range at a flow

rate of 500 US gallons per minute (32 L/s), while a desilter (4 inches (100 mm) Cone) is able to remove

50% of solids within the 15-20 μm range at a flow rate of 60 US gallons per minute (3.8 L/s). Micro-fine

separators are able to remove 50% of solids within the 10-15 μm range at a flow rate of 15 US gallons per

minute (0.95 L/s). A desander is typically positioned next-to-last in the arrangement of solids control

equipment, with a decanter centrifuge as the subsequent processing unit. Desanders are preceded by gas

busters, gumbo removal equipment (if utilized), shale shaker, mud cleaner (if utilized) and a vacuum

degasser. Desanders are widely used in oilfield drilling. Practice has proved that hydrocyclone desanders

are economic and effective equipment.

3. DESILTER

Desilter is the third stage solids control and fourth stage drilling mud cleaning equipment in the drilling

fluids recycling system. GN Desilter commonly adapts 4” cyclone which could separate the solid phase

particles with size of 15-25 microns. GN Desilter is designed 2 options of with and without underflow

screen for customers’ requirement.

The desilter with underflow shaker is also called Mini cleaner which is applicable for both weighted and

unweighted drilling mud, while traditional desander no underflow vibrating screen only for unweighted

drilling fluids. And comparing with large size desander and desilter assembly, the Mini Desander is cost-

effective. For compact mud system used in HDD, CBM, water well drilling and mining project, Mini

desilter cleaner is an ideal choice.

4. DEGASSER A degasser is a device used in drilling to remove gasses from drilling fluid which could otherwise

form bubbles. For small amount of entrained gas in a drilling fluid, the degasser can play a major role of

removing small bubbles that a liquid film has enveloped and entrapped. In order for it to be released and

break out the air and gas such as methane, H2S and CO2 from the mud to the surface, the drilling fluid

must pass degassing technique and it can be accomplished by the equipment called degasser which is also

a major part of a mud systems.

CASING

Casing is large diameter pipe that is assembled and inserted into a

recently drilled section of a borehole and typically held into place

with cement.

Purpose :- Casing that is cemented in place aids the drilling

process in several ways:

Prevent contamination of fresh water well zones.

Prevent unstable upper formations from caving-in and

sticking the drill string or forming large caverns.

Provides a strong upper foundation to use high-

density drilling fluid to continue drilling deeper.

Isolates different zones, that may have

different pressures or fluids - known as zonal isolation, in

the drilled formations from one another.

Seals off high pressure zones from the surface, avoiding

potential for a blowout.

Prevents fluid loss into or contamination of production

zones.

Provides a smooth internal bore for installing production

equipment.

Design :- In the planning stages of a well a drilling engineer, usually with input from geologists and

others, will pick strategic depths at which the hole will need to be cased in order for drilling to reach the

desired total depth. This decision is often based on subsurface data such as formation pressures, strengths,

and makeup, and is balanced against the cost objectives and desired drilling strategy.

With the casing set depths determined, hole sizes and casing sizes must follow. The hole drilled for

each casing string must be large enough to easily fit the casing inside it, allowing room for cement

between the outside of the casing and the hole. Also, the inside diameter of the first casing string must be

large enough to fit the second bit that will continue drilling. Thus, each casing string will have a

subsequently smaller diameter.

The inside diameter of the final casing string (or penultimate one in some instances of a liner completion)

must accommodate the production tubing and associated hardware such as packers, gas lift mandrels and

subsurface safety valves.

Casing design for each size is done by calculating the worst conditions that may be faced during drilling

and production. Mechanical properties of designed pipes such as collapse resistance, burst pressure, and

axial tensile strength must be sufficient for the worst conditions.

Casing strings are supported by casing hangers that are set in the wellhead, which later will be topped

with the Christmas tree. The wellhead usually is installed on top of the first casing string after it has been

cemented in place.

Typically, a well contains multiple intervals of casing successively placed within the previous casing run.

The following casing intervals are typically used in an oil or gas well:

Conductor casing

Surface casing

Intermediate casing (optional)

Production casing

Production liner

The conductor casing serves as a support during drilling operations, to flow back returns during drilling

and cementing of the surface casing, and to prevent collapse of the loose soil near the surface. It can

normally vary from sizes such as 18" to 30".

The purpose of surface casing is to isolate freshwater zones so that they are not contaminated during

drilling and completion. Surface casing is the most strictly regulated due to these environmental concerns,

which can include regulation of casing depth and cement quality. A typical size of surface casing is 13⅜

inches.

Intermediate casing may be necessary on longer drilling intervals where necessary drilling mud weight to

prevent blowouts may cause a hydrostatic pressure that can fracture shallower or deeper formations.

Casing placement is selected so that the hydrostatic pressure of the drilling fluid remains between In order

to reduce cost, a liner may be used which extends just above the shoe (bottom) of the previous casing

interval and hung off downhole rather than at the surface. It may typically be 7", although many liners

match the diameter of the production tubing.

Few wells actually produce through casing, since producing fluids can corrode steel or form deposits such

as asphaltenes or paraffin waxes and the larger diameter can make flow unstable. Production tubing is

therefore installed inside the last casing string and the tubing annulus is usually sealed at the bottom of

the tubing by a packer. Tubing is easier to remove for maintenance, replacement, or for various types of

workover operations. It is significantly lighter than casing and does not require a drilling rig to run in and

out of hole; smaller "service rigs" are used for this purpose.

Cementing is performed by circulating a cement slurry through the inside of the casing and out into the

annulus through the casing shoe at the bottom of the casing string. In order to precisely place the cement

slurry at a required interval on the outside of the casing, a plug is pumped with a displacement fluid

behind the cement slurry column, which "bumps" in the casing shoe and prevents further flow of fluid

through the shoe. This bump can be seen at surface as a pressure spike at the cement pump. To prevent

the cement from flowing back into the inside of the casing, a float collar above the casing shoe acts as

a check valve and prevents fluid from flowing up through the shoe from the annulus.

Types of Casing Policies :- Generally there are two types of Casing Policies (CP)

1. 3 CP – For lower depths

1st Stage 2

nd Stage 3

rd Stage

Depth(in metre) < 400 < 2000 < 3000

Casing Size(in inch) 13(3/8) 9(5/8) 5(1/2)

Bit Size(in inch) 17(1/2) 9(5/8) 8(1/2)

1. 4 CP – For higher depths

1st Stage 2

nd Stage 3

rd Stage 4

th Stage

Depth 400-450 2000-2500 3000-3500 > 4000

Casing Size(in inch) 20 13(3/8) 9(5/8) 5(1/2)

Bit Size(in inch) 26 17(1/2) 9(5/8) 8(1/2)

HOW A WELL IS DRILLED ON LAND:

Step 1: Digging a Cellar

On land, a majority of wells begin with digging a cellar from three to fifteen feet in depth. The purpose of

a cellar is to align the production Christmas tree at ground level, providing easier access to the valves,

chokes, and other equipment.

Step 2: Running a Conductor Pipe

The first string of pipe used in a well is called the conductor pipe, or drive pipe. The pipe is usually 30-36

inches in diameter. A large diameter hole is drilled to a specified depth, usually one or two hundred feet,

and the pipe is driven into the ground.

Step 3: Connecting the BOP

An adapter flange, or drilling flange, is welded to the conductor pipe to connect a diverter system or a

blowout preventer system to control wellhead pressure.

Step 4: Running the Surface Pipe

A hole is drilled for the well’s first string of pipe, the surface pipe, and the pipe is run in the hole. There

may be several strings of pipe in a well, each run to a different depth. The number of strings is determined

by the number of zones being drilled through. These can include fresh water, salt water, and potential

production zones. Each zone is isolated, or cased off, until it is to be produced.

Step 5: Connecting the Surface Pipe

The surface pipe is cemented in place back to the surface. This holds the pipe in place and seals off the

zone. A cement plug is left in the pipe so that the BOP system may be disconnected safely. The BOP is

then removed from the adapter flange.

Step 6: Cutting the Conductor Pipe and Surface Casing The surface pipe is drained, the adapter flange (or drilling flange) is cut off, and both the conductor pipe

and the surface casing are cut to the proper height to allow the top of the completed wellhead to be at

ground level.

Step 7: Installing the Casing Head Housing and Base Plate The casing head housing is welded in place on the inside diameter and the outside diameter of the surface

casing. The housing is then tested to assure there are no leak paths in the welds.

Step 8: Installing the BOP System The BOP system is installed above the casing head housing and then tested. To test the BOP system, the

test plug is made up on the drill string and lowered through the BOP system onto the casing head bowl.

Pressure is applied from above the plug to test the BOP system

Step 9: Installing the Casing Head Wear Bushing A wear bushing is installed to protect the interior of the casing head from damage by drilling equipment.

Step 10: Installing the Intermediate String A hole is drilled for the intermediate string and the casing is run in the hole and cemented in place. A

cement plug is left in the intermediate casing, just as it was in the surface casing.

Step 11: Installing the Casing Hanger and Casing Spool The intermediate casing is suspended from the block above the rig floor, the BOP is picked up, and the

casing hanger is installed on top of the casing head. Holes are cut in the casing to allow the drilling fluids

to drain out of the casing riser. When the fluid has drained, the casing is cut off to the appropriate height

and the casing spool is installed.

Step 12: Installing the BOP System The BOP system is installed above the casing spool and then tested. To test the BOP system, the test plug

is made up on the drill string and lowered through the BOP system onto the casing head bowl. Pressure is

applied from above the plug to test the BOP system.

Step 13: Installing the Wear Bushing The wear bushing running tool is made up on the drill string and the wear bushing installed on the

running tool. The wear bushing is then lowered through the BOP system, until it rests in the casing spool

bowl, and then is locked into place. The running tool is removed and drilling resumes.

Step 14: Running the Production Casing String The production casing string is usually run to the total depth of the well. A hole is drilled for the

production casing and the casing is run in the hole and cemented into place. A cement plug is left in the

production casing, as in the previous steps.

Step 15: Installing the Casing Hanger and Tubing Spool The production casing is suspended from the elevators at the rig floor, the BOP is picked up, and the

production casing hanger is installed in the same way as the previous casing hanger. The tubing spool is

installed in the same way as the casing spool. After the spool has been installed, the seals and connections

are tested, and the BOP system is reinstalled.

Step 16: Running the Production Tubing The production tubing is installed inside the production casing. Unlike casing, the production tubing is

not cemented in the well so it may be removed later, if necessary

Step 17: Installing the Down hole Packer Assembly A down hole packer assembly (a type of seal assembly) is run and installed in the production casing to

seal the reservoir from all strings of pipe, except the production tubing.

Step 18: Installing the Tubing Hanger The tubing hanger is installed on the tubing at the rig floor, and then lowered into the bowl of the tubing

spool. The packer seals are tested, and a backpressure valve is installed in the tubing hanger so that the

BOP can be removed safely. After the valve has been installed the BOP is removed.

Step 19: Installing the Christmas Tree The production Christmas tree, sometimes called the flow assembly, controls the flow of the well. It is

made up of a seal flange, or tubing head adapter, a series of valves, and a choke. The valves are stacked

vertically and horizontally to provide backup should a valve fail. Each Christmas tree has at least one

actuated surface safety valve to shut down the well in an emergency and prevent damage to equipment

downstream. The Christmas tree is connected to a flow line, which transports the well’s fluid or gas.

The Christmas tree is oriented properly, picked up, lowered over the neck of the tubing hanger, and

connected to the tubing spool. The connections and seals are tested, and the well is now ready for

production testing.

REFERENCES

1. MD Totco Manuals

2. Wikipedia

3. Google

4. Sensor Manuals

5. National Oil Varco (nov.com)