sucker rod pump

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SUCKER ROD PUMP 1. INTRODUCTION 1.1 WHAT IS OIL WELL? An oil well is a general term for any boring through the earth's surface that is designed to find and acquire petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil. A well that is designed to produce mainly or only gas may be termed a gas well. 1.2 SUCKER ROD PUMP The over ground drive for a reciprocating piston pump installed at a borehole (e.g. an oil well).A special steel pumping rod. Several rods screwed together make up the mechanical link from the beam pump ing unit on the surface to the sucker rod pump at the bottom of a well. Sucker rods are threaded on each end and manufactured to dimension standards and metal specifications set by the petroleum industry. Lengths are 25 or 30 feet (7.6 or 9.1 meters); diameter varies from 1/2 to 1-1/8 inches (12 to 30 millimetres). there is also a continuous sucker rod (trade name: corod).A pump jack (also known as nodding donkey, pumping unit, horse head pump, beam pump, sucker rod pump (SRP), grasshopper pump, thirsty bird and jack pump) is the over ground drive for a reciprocating piston pump installed in an oil well. It is used to mechanically lift liquid out of the well if there is not enough bottom hole pressure for the liquid to S.S.G.B.C.O.E&T Page 1

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Page 1: Sucker Rod Pump

SUCKER ROD PUMP

1. INTRODUCTION

1.1 WHAT IS OIL WELL?

An oil well is a general term for any boring through the earth's surface that is

designed to find and acquire petroleum oil hydrocarbons. Usually some natural gas is

produced along with the oil. A well that is designed to produce mainly or only gas may be

termed a gas well.

1.2 SUCKER ROD PUMP

The over ground drive for a reciprocating piston pump installed at a borehole (e.g.

an oil well).A special steel pumping rod. Several rods screwed together make up the

mechanical link from the beam  pump ing unit on the surface to the sucker   rod   pump  at the

bottom of a well. Sucker rods are threaded on each end and manufactured to dimension

standards and metal specifications set by the petroleum industry. Lengths are 25 or 30

feet (7.6 or 9.1 meters); diameter varies from 1/2 to 1-1/8 inches (12 to 30 millimetres).

there is also a continuous sucker rod (trade name: corod).A pump jack (also known

as nodding donkey, pumping unit, horse head pump, beam pump, sucker rod pump

(SRP), grasshopper pump, thirsty bird and jack pump) is the over ground drive for a

reciprocating piston pump installed in an oil well.

It is used to mechanically lift liquid out of the well if there is not enough bottom hole

pressure for the liquid to flow all the way to the surface. The arrangement is commonly

used for onshore wells producing relatively little oil. Pumpjacks are common in

many oil-rich areas, dotting the countryside and occasionally serving as

local landmarks.

Depending on the size of the pump, it generally produces 5 to 40 litres of liquid at each

stroke. Often this is an emulsion of oil and water. The size of the pump is also

determined by the depth and weight of the oil to be removed, with deeper extraction

requiring more power to move the heavier lengths of sucker rods (see diagram at right).

A pump jack converts the rotary mechanism of the motor to a vertical reciprocating

motion to drive the pump shaft, and is exhibited in the characteristic nodding motion.

The engineering term for this type of mechanism is a walking beam. It was often

employed in stationary and marine steam engine designs in the 18th and 19th centuries.

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2. LITERATURE SURVEY

Gipson and Swaim did an excellent job of summarizing a sucker-rod lift-system

design in The Beam Pump Design Chain with the API RP 11L approach. This

recommended practice should be consulted for continued discussion of this equipment,

along with a review of a sample problem and a recommended solution. In summary, use

the design procedure presented in API RP 11L or a suitable wave equation. Several

commercial wave-equation computer programs are available that many operators have

successfully used.

2.1 BEAM-PUMPING SYSTEMS

Beam pumping, or the sucker-rod lift method, is the oldest and most widely used

type of artificial lift for most wells. A sucker-rod pumping system is made up of several

components, some of which operate aboveground and other parts of which operate

underground, down in the well. The surface-pumping unit, which drives the underground

pump, consists of a prime mover (usually an electric motor) and, normally, a beam fixed

to a pivotal post. The post is called a Sampson post, and the beam is normally called a

walking beam. Figs. 2.1 and 2.2 present detailed schematics of a typical beam-pump

installation.

This system allows the beam to rock back and forth, moving the downhole components

up and down in the process. The entire surface system is run by a prime mover, V-belt

drives, and a gearbox with a crank mechanism on it. When this type of system is used, it

is usually called a beam-pump installation. However, other types of surface-pumping

units can be used, including hydraulically actuated units (with and without some type of

counterbalancing system), or even tall-tower systems that use a chain or belt to allow

long strokes and slow pumping speeds. The more-generic name of sucker-rod lift, or

sucker-rod pumping, should be used to refer to all types of reciprocating rod-lift methods.

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3. THEORY

3.1 PARAMETER FOR SELECTING THE SUCKER-ROD PUMPING

METHOD

Many factors must be considered when determining the most appropriate lift

system for a particular well. Artificial presents a discussion of the normally available

artificial-lift techniques, their advantages and disadvantages, and the selection of a

method for a well installation.

Sucker-rod pumping systems should be considered for new, lower volume stripper wells,

because they have proved to be cost effective over time. Operating personnel usually are

familiar with these mechanically simple systems and can operate them efficiently.

Inexperienced personnel also can operate rod pumps more effectively than other types of

artificial lift. Most of these systems have a high salvage value.

Because of its long history of successfully lifting well fluids, the sucker-rod lift method is

normally considered the first choice for most onshore, and even some offshore,

installations all over the world. This method is limited by:

Size of the casing, tubing, and downhole pump

Strength and size of the various rods

Speed with which they can be reciprocated

Under favourable conditions, approximately 150 BFPD can be lifted from greater than

14,000 ft, while more than 3,000

3.2 COMPONENTS OF SUCKER-ROD LIFT SYSTEM

The major components of a sucker-rod lift system are discussed in separate articles:

Downhole sucker-rod pumps

Sucker rods

Miscellaneous downhole equipment

Sucker-rod pumping units

Prime movers

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3.3 OPERATION OF THE PUMP

A motor and gearbox supply power to turn the power shaft. There is a

counterweight at the end of the crank. A pitman arm is attached to the crank and it moves

upward when the crank moves counter clockwise. The Samson arms support the walking

beam. The walking beam pivots and lowers or raises the plunger. The rod attaches the

plunger to the horsehead. The horsehead (not rigidly attached) allows the joint (where rod

is attached) to move in a vertical path instead of following an arc. Every time the plunger

rises, oil is pumped out through a spout. The pump consist of a four bar linkage is

comprised of the crank, the pitman arm, the walking beam, and the ground.

Here the plunger is shown at its lowest position. The pitman arm and the crank are in-

line. The maximum pumping angle, denoted as theta in the calculations, is shown. L is

the stroke length. After one stroke, the plunger moves upward by one stroke length and

the walking beam pivots. The crank also rotates counter clockwise. At the end of the

upstroke the pitman arm, the crank, and the walking beam are in-line.

For name and location of parts, see Fig.3.1.

1. A motor supplies power to a gear box. A gearbox reduces the angular velocity and

increases the torque relative to this input.

2. As shown in Fig.3.2, (the crank turns counter clockwise) and lifts the

counterweight. Since the crank is connected to the walking beam via the pitman

arm, the beam pivots and submerges the plunger. Figure B also shows the

horsehead at its lowest position. This marks the end of the down stroke. Note that

the crank and the pitman arm are in-line at this position.

3. The upstroke raises the horsehead and the plunger, along with the fluid being

pumped. The upstroke begins at the point shown in Fig.3.2. At the end of the

upstroke, all joints are in-line. This geometric constraint determines the length of

the pitman arm.

4. Figures 3.3 show the plunger and ball valves in more detail. These valves are

opened by fluid flow alone. On the upstroke, the riding valve is closed and the

standing valve is open. Fluid above and within the plunger is lifted out of the

casing while more fluid is pumped into the well. On the down stroke, the riding

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valve is opened and the standing valve is closed. Fluid flows into the plunger and

no fluid is allowed to leave the well.

4. COMPONENTS AND DESCRIPTION

4.1 GEAR BOX ARRANGEMENT:

The simple gear box arrangement is fixed to the frame stand. In front of the stand to

reduce the speed of motor and increase the torque to driven shaft Most modern gearboxes

are used to increase torque while reducing the speed of a prime mover output shaft (e.g. a

motor crankshaft). This means that the output shaft of a gearbox rotates at a slower rate

than the input shaft, and this reduction in speed produces a mechanical advantage,

increasing torque. A gearbox can be set up to do the opposite and provide an increase in

shaft speed with a reduction of torque. Some of the simplest gearboxes merely change the

physical rotational direction of power transmission.

4.2 PULLEY BELT ARRANGEMENT:

A belt is a loop of flexible material used to mechanically link two or more rotating

shafts, most often parallel. Belts may be used as a source of motion, to transmit power

efficiently, or to track relative movement. Belts are looped over pulleys and may have a

twist between the pulleys, and the shafts need not be parallel. In a two pulley system, the

belt can either drive the pulleys normally in one direction (the same if on parallel shafts),

or the belt may be crossed, so that the direction of the driven shaft is reversed (the

opposite direction to the driver if on parallel shafts). As a source of motion, a conveyor

belt is one application where the belt is adapted to continuously carry a load between two

points

V belts (also style V-belts, vee belts, or, less commonly, wedge rope) solved the slippage

and alignment problem. It is now the basic belt for power transmission. They provide the

best combination of traction, speed of movement, load of the bearings, and long service

life. They are generally endless, and their general cross-section shape is trapezoidal

(hence the name "V"). The "V" shape of the belt tracks in a mating groove in the pulley

(or sheave), with the result that the belt cannot slip off. The belt also tends to wedge into

the groove as the load increases—the greater the load, the greater the wedging action—

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improving torque transmission and making the V-belt an effective solution, needing less

width and tension than flat belts. V-belts trump flat belts with their small centre distances

and high reduction ratios. The preferred centre distance is larger than the largest pulley

diameter, but less than three times the sum of both pulleys. Optimal speed range is 1,000–

7,000 ft/min (300–2,130 m/min). V-belts need larger pulleys for their thicker cross-

section than flat belts.

For high-power requirements, two or more V-belts can be joined side-by-side in an

arrangement called a multi-V, running on matching multi-groove sheaves. This is known

as a multiple-V-belt drive (or sometimes a "classical V-belt drive").

V-belts may be homogeneously rubber or polymer throughout or there may be fibres

embedded in the rubber or polymer for strength and reinforcement. The fibres may be of

textile materials such as cotton, polyamide (such as Nylon) or polyester or, for greatest

strength, of steel or aramid (such as Twaron or Kevlar).

When an endless belt does not fit the need, jointed and link V-belts may be employed.

Most models offer the same power and speed ratings as equivalently-sized endless belts

and do not require special pulleys to operate. A link v-belt is a number of

polyurethane/polyester composite links held together, either by themselves, such as

Fenner Drives' Power Twist, or by metal studs, such as Gates' Nu-T-Link. These provide

easy installation and superior environmental resistance compared to rubber belts and is

length adjustable by disassembling and removing links when needed.

4.3 STAND:

This is a supporting frame and made up of mild steel.

4.4 SINGLE PHASE INDUCTION MOTOR WITH PULLEY:-

This is used to drive the wheel by using two pulleys with belt drive mechanism.

4.4.1 SINGLE-PHASE THEORY

Because it has but a single alternating current source, a single-phase motor can only

produce an alternating field: one that pulls first in one direction, then in the opposite as

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the polarity of the field switches. A squirrel-cage rotor placed in this field would merely

twitch, since there would be no moment upon it. If pushed in one direction, however, it

would spin.

The major distinction between the different types of single-phase AC motors is how they

go about starting the rotor in a particular direction such that the alternating field will

produce rotary motion in the desired direction. This is usually done by some device that

introduces a phase-shifted magnetic field on one side of the rotor.

4.5 PULLEYS:

There are two pulleys are used in our project. One is coupled with motor shaft and

another one is coupled to the wheel. These two pulleys are connected by belt drive.

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5. DOMINANT PHYSICS & DESIGN:

Table 5.1: Variable Descriptions, Values and Units

Variable Description Typical Value Units

ϴ Full Pump Angle --- degrees

Fl Total Force Pump must exert --- lbs

Ff Weight of Fluid --- lbs

Fr Weight of the Rods --- lbs

Fc Weight of counterweight --- lbs

Fb Buoyant force on rods --- lbs

W Rod weight per unit length --- lbs/ft

Lr Length of one rod 25 - 30§ ft

Nr Number of Rods --- ---

Pi Input Power 4000§§ psi

H Depth of Well 10,000§§§ ft

ϼ Fluid Density --- lbm/in^3

G Gravitational Acceleration

Constant

~9.8 m/s^2

L Stroke Length 16 - 192§§§§ in

T Required Pumping Torque 6,400 - 912,000§§§§§ in-lb

Vf Fluid Volume per Stroke --- ft^3

Ar Rod Cross sectional area --- psi

Sy Yield Strength of Rod --- psi

Ap Plunger Cross Sectional Area --- psi

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To design a sucker rod pump, the depth of the well must first be determined. This value is

then used to calculate the amount of fluid that can be pumped per stroke. This amount is

the volume of fluid that fits in a cylinder of height L and cross sectional area Ap.

Vf = Ap L

This volume is then multiplied by the density of the fluid and by the g to find the weight

of the column of fluid the pump must lift.

Ff = Mfϼg

The pump must also provide enough power to lift the sucker rods (see Figure A).

Manufacturers specify typical values of weight per unit length, w, for the rods they make.

This number is multiplied by the length of one rod, Lr, and by the number of rods, Nr.

Fr = w Lr Nr

Since the rods are submerged in fluid, a buoyant force is present. This force is found

using Archimedes’ Principle. It states that the buoyant force a submerged object feels is

equal to the weight of the fluid it displaces. Therefore, the volume of displaced fluid is

equal to the submerged volume of the rods. The weight of this fluid is equal to this

volume multiplied by the fluid’s density and g. To obtain the volume of the rods, we

multiply their cross sectional area by their total length.

Fb = Ar Nr Lr ϼ g

Now the total load the pump must lift can be calculated.

Fl = Ff + (Fr – Fb)

Two things must be noted. First, the above analysis is very rough and does not include

additional factors such as impulse forces. Also, the forces described above vary with time

and this must be taken into account.

The stroke length of the pump is the vertical distance the plunger travels in one stroke.

This length depends on the amount of fluid being pumped. Once the stroke length is

known, the geometry of the four bar linkage can be determined. To avoid excessive wear

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of the machinery, it is good engineering practice to reduce the number of cycles the pump

completes per unit of time. In order to do this more fluid should be pumped per cycle. In

order to increase the fluid displacement, the stroke length should be maximized. Typical

values for stroke length vary from 16 to 192 inches. The stroke length can be used to

calculate the torque required to pump the oil according to the following formula.

T = C L Fl

Here, C is a function of the geometry of the four bar linkage and the force the

counterweight exerts on the crank. Typical values for torque range from 6,400 to 912,000

in-lb.

On the upstroke, two forces help pump the oil from the well. The first is

the "force" supplied from the torque produced by the motor and gearbox. The second

force comes from the weight of the counterweight as it falls.

5.2 LIMITING PHYSICS:

Care must be taken to choose a cross sectional area large enough so that the rods do not

yield. This area can be found by dividing the total tensile load by the yield stress of the

material.

Ay = Fl / Sy

The area of the rods must be greater than this area.  This is a minimum.  Fatigue affects

(function of material and loading) will require a larger value.

5.3 EFFICIENCY:

The efficiency of the sucker rod pump can be defined as the volume of oil

it actually pumps divided by the volume it can theoretically pump. When the well is

initially drilled, the oil contains a lot of gas. This gas displaces a small volume of oil at

the beginning. This volume decreases eventually. The volumetric efficiency of this type

of pump is rated at about 80%.

5.4 WHERE TO FIND SUCKER ROD PUMPS:

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Sucker rod pumps are used primarily to draw oil from underground reservoirs. The

mechanisms it employs however are found in a wide variety of machines. The four bar

linkage can be found on door dampers, on automobile engines, and on devices such as the

lazy tong. The Sterling engines manufactured in 2.670 also use a linkage similar to the

one used by the pump.

5.5 Bearing design

Bearing Type = Deep Groove Ball Bearing

(1) d = 6 mm

D = 20 mm

B = 8 mm

Basic load capacity, C

C = 3924 N

Limiting speed, n

n = 20000 rpm

Mass, m

m = 0.020 Kg

Designation - SKF 6001

(2) d = 17mm

D = 35 mm

B = 10 mm

Basic load capacity, C

C = 4562 N

Limiting speed, n

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n = 20000 rpm

Mass, m

m = 0.040 Kg

Designation - SKF 6003

5.6 Design of bearing housing

Name of part – Bearing Housing

Qty – 44

Material – Aluminum

For small bearing

Tolerances on inner race in mm

On mean diameter 120.000−0.008

Circularity -0.011

+0.003

Width 0.000

-0.120

Radial runout 0.010

Tolerances on outer race in mm

On mean diameter 28−0.0110.000

Circularity +0.003

-0.014

Radial runout 0.020

For large bearing

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Tolerances on inner race in mm

On mean diameter 170.000−0.008

Circularity -0.011

+0.003

Width 0.000

-0.120

Radial runout 0.010

Tolerances on outer race in mm

On mean diameter 35−0.0130.000

Radial runout 0.025

5.7 Screw selection

Screw type: Counter sunk screws

(1) Size- M3 (2) Size- M6

d = 3 mm d = 6 mm

l = 10 mm l = 20 mm

(3) Size- M3 (4) Size- M3

d = 3 mm d = 3 mm

l = 6 mm l = 6 mm

(5) Size- M5

d = 5 mm

l = 20 mm

5.8 Gear design

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Given Data:-

Zp = 15 ; Zg = 30

dp = 30mm ; dg = 60mm

Ka = 1 ; Km = 1.6

np = 7.5 rpm ; ng = 15 rpm

T = 367.875 N-m ; σu = 56 N/mm²

Grade 12 ; Φ = 20°

b= 10 mm ; Material – Acetal (Delrin)

Bending Stress σb = σu / 2.5

= 22.4 N/mm²

Yp = 0.289

Yg = 0.358

(σb *Yp) = 6.4736 N/mm²

(σb *Yg) = 8.0192 N/mm²

As (σb *Yp) < (σb *Yg) pinion is weaker in bending hence it is necessary to design

pinion for bending.

Bending Strength:

Fb = σb*m*b*Yp

= 129.472 N

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Wear Strength:

dp = m*Zp

= 30mm

Q =

= 1.33

K = 1.05 N/mm²

Fw = dp*b*Q*K

= 418.95 N

As Fb<Fw gear pair is weaker in bending & hence it should be designed for safety

against pitting failure.

Effective Load:

V = ( *dp*np) / (60*1000)

= 0.0117 m/s

P = (2* *n*T) / (60*1000)

= 577.85 KW

Ft = P/V

= 49.38 N

Kv = 3/ (3+V)

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= 0.996

Feff = (Ka*Km*Ft) / Kv

= 79.31 N

Fb = Nf * Feff

Nf = 1.59

Check for Design:

ep = 79.84*10^-3 mm

eg = 82.68*10^-3 mm

e = ep+ eg

= 165.52*10^-3 mm.

Buckingham’s Equation:

Fd =

Ft = 49.38 N.

Ftmax = Ka*Km *Ft

V = 0.0117 m/s

C = K*e *[ ]

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Fd = 2.1252 N

Feff = 81.10 N

Nf =

= 1.6 1.59

Therefore available Factor of safety is same as required. Therefore the gear pair is safe

against bending failure.

6. LIST OF COMPONENTS

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SL.

NO.

NAME OF THE PARTS MATERIAL(Operation) QUANTITY

1 Frame M.S.(fitting) 1

2 Pendulam M.S.(fitting) 1

3 Pump M.S 1

4 Bearing Steel 2

5 Connecting lever M.S(cutting,welding) 1

6 Valve rubber,plastic 2

7 Frame Stand 0.75 inch angle

M.S(Cutting,Welding

1

9 Screw M.S 1

10 Shaft M.S 1

7. COSTING

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7.1 MATERIAL COST:

SL.

NO.

NAME OF

THE PARTS

MATERIAL(Operation) QUANTITY APPROX

AMOUNT(RS)/each

1 Frame M.S.(fitting) 1 3200

2 Pendulam M.S.(fitting) 1 1900

3 Pump M.S 1 1750

4 Bearing Steel 2 250

5 Connecting

lever

M.S(cutting,welding) 1 950

6 Valve rubber,plastic 2 350

7 Frame Stand 0.75 inch angle

M.S(Cutting,Welding

1 2550

9 Screw M.S 1 250

10 Shaft M.S 1 650

TOTAL COST = 11850

7.2 LABOUR COST

LATHE, DRILLING, WELDING, GRINDING, POWER HACKSAW, GAS CUTTING:

Cost = 2000/-

7.3 OVERHEAD CHARGES

The overhead charges are arrived by “Manufacturing cost”

Manufacturing Cost = Material Cost + Labour cost

= 11850+2000

= 13850

Overhead Charges = 20% of the manufacturing cost

= 2770

7.4 TOTAL COST

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Total cost = Material Cost + Labour cost + Overhead Charges

= 11850+2000 +2770 =16620

Total cost for this project =16620

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8. ADVANTAGES

8.1 Economical aspect:

a) Least maintenance cost.

b) No rent for electricity utilized

c) No fuel required for operation

8.2 Technical aspect:

a) Noiseless operation

b) No person required to operate the system

c) Simple in construction, so easy to fabricate

d) Pollution free

e) Less chance of accidents

9. LIMITATIONS

9.1 Economical aspects

a) High initial installation cost

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10. CONCLUSION

The fabrication of Sucker Rod Pump was successfully completed as per the

specification.

The trial performance of this device provides to be successful, with case of

operation and safety, hence the results has given a clear indication of its commercial

viability. The cost analysis has shown its economic feasibility and we are under the

impression that it can be further reduced, when produced on a mass scale.

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