BEAM PUMPING UNITS BEAM PUMPING UNITS

The Beam Pumping units (pumpjack or surface pumping unit) is used to stroke the bottom hole

pump up and down so that it will pump reservoir fluids to surface

This is accomplished by converting rotary motion to reciprocating vertical motion.

Rotary power is supplied to a gearbox by an

electric motor or gas engine.

The gearbox uses a series of gears to convert

this high speed power to low speed power. (Usually a ratio of approximately 30 to 1 on a

double reduction unit.)

the gearbox turns the cranks and the cranks lift the pitman arms up and down (rotary to reciprocating).

The pitman arms move the walking beam up and down consequently the horses head on the opposite

end of the walking beam has to go up and down.

This action causes the bridle cable to move the carrier bar up and down which in turn moves the sucker rod system up and down and consequently

the traveling valve which connect to plunger.

Pumping units Components

The smallest API jack has a gearbox that can

handle 6400 inch pounds of torque. It is a structure that can handle 3200 pounds polish

rod load and has a maximum stroke length of 16".

The API designation of this jack is 64-3.2-16.

On the other end of the scale, the largest unit On the other end of the scale, the largest unit

has a 3,648,000 inch pound gearbox, can has a 3,648,000 inch pound gearbox, can

handle 47,000 pound load and has a 300" handle 47,000 pound load and has a 300"

maximum stroke length! maximum stroke length!

The API designation of this jack is 3648The API designation of this jack is 3648--470470--

300. 300.

PUMPING UNIT DESIGNATIONSPUMPING UNIT DESIGNATIONS

PUMPJACK CONFIGURATION

There are numerous There are numerous

pumping unit configurations pumping unit configurations

�� A A -- Air BalanceAir Balance

�� B B -- Beam BalanceBeam Balance

�� C C -- ConventionalConventional

�� M M -- Mark IIMark II

�� LP LP -- Low Profile Low Profile

�� RM RM -- Reverse Mark Reverse Mark

�� CM CM -- Conventional PortableConventional Portable

The "Conventional" unit has the sampson post

in the middle and is the most common jack configuration

Conventional unit

Conventional Pumping unitConventional Pumping unit

�� The classical Conventional geometry is organized so that The classical Conventional geometry is organized so that when the walking beam is horizontalwhen the walking beam is horizontal, the , the equalizer equalizer bearingbearing lies directly over the lies directly over the center of the crankshaft. center of the crankshaft.

�� As a direct result of this arrangement, the As a direct result of this arrangement, the upstroke upstroke occurs in approximately 180occurs in approximately 180°°of crank rotation, and the of crank rotation, and the downstrokedownstroke occurs in the remaining 180occurs in the remaining 180°°of crank of crank rotation. rotation.

�� This geometry is truly a byThis geometry is truly a by--directional machine. That is, directional machine. That is, its its performance in both the clockwise and counter performance in both the clockwise and counter clockwiseclockwise rotation is approximately the rotation is approximately the same.same.

Conventional pumping unit Conventional pumping unit

( class one)( class one)

Some of conventional pumping Some of conventional pumping

units configurationsunits configurations

Mark II pumping unitMark II pumping unit

Mark II" has the Sampson post at the back of Mark II" has the Sampson post at the back of

the unit and the gearbox in the middle. the unit and the gearbox in the middle.

Mark II pumping unitMark II pumping unit

The advantage is that the rods are The advantage is that the rods are travellingtravellingslower on the upstroke than on the slower on the upstroke than on the downstrokedownstroke so torque is more even.so torque is more even.

This speed variance is good in light oil or This speed variance is good in light oil or high high watercutwatercut shallow wells but in heavier shallow wells but in heavier viscosity wells, the rods hang up more viscosity wells, the rods hang up more easily. Higher torque can result. easily. Higher torque can result.

�� The Mark II pumping unit is a The Mark II pumping unit is a class three leverclass three leversystem, system,

�� It is differs from a Conventional geometry in that the It is differs from a Conventional geometry in that the walking beam pivots off of the rear end of the beam walking beam pivots off of the rear end of the beam rather than about the center of the beam as does a rather than about the center of the beam as does a Conventional unit. Conventional unit.

�� Mark II geometry lifts the well through a pitman Mark II geometry lifts the well through a pitman arrangement that pushes up on the front end of the arrangement that pushes up on the front end of the walking beam as apposed to the Conventional walking beam as apposed to the Conventional pitman, which pulls down on the rear end of the pitman, which pulls down on the rear end of the walking beam.walking beam.

Mark II Pumping UnitsMark II Pumping Units

why the Mark II generally has lower why the Mark II generally has lower

polished rod loads than the polished rod loads than the

Conventional unit.Conventional unit.

�� The characteristics of the Mark II geometry The characteristics of the Mark II geometry

cause the polish rod to begin the upstroke cause the polish rod to begin the upstroke

portion of the cycle at a low acceleration and portion of the cycle at a low acceleration and

come down off the top of the stroke at a come down off the top of the stroke at a

higher acceleration. higher acceleration.

�� The Mark II geometry, having the class three The Mark II geometry, having the class three lever system, phased counterbalanced, lever system, phased counterbalanced, gearbox offset from under the equalizer, and gearbox offset from under the equalizer, and preferred direction of rotation , generally preferred direction of rotation , generally reduces the torque due to the well load over reduces the torque due to the well load over that of a Conventional geometry. that of a Conventional geometry.

�� the class three lever system creates an even the class three lever system creates an even lower off bottom acceleration. lower off bottom acceleration.

why the Mark II generally has lower why the Mark II generally has lower

polished rod loads than the polished rod loads than the

Conventional unit.Conventional unit.

• Placing the equalizer between the horsehead and the Samson post creates a “push-up” or “Class 3”lever system.

• The 195°upstroke, coupled with the front mounted geometry, reduces the acceleration at the beginning of the upstroke where the load is greatest, thereby effecting a reduction in polished rod load.

Air Balanced UnitsAir Balanced Units

Air Balanced UnitsAir Balanced Units

�� counterbalance can be achieved using an air counterbalance can be achieved using an air cylinder instead of metal counterweights. cylinder instead of metal counterweights.

�� This configuration requires an air compressor This configuration requires an air compressor to maintain proper air pressure for correct to maintain proper air pressure for correct counterbalance. counterbalance.

�� Maintenance is always higher on machinery Maintenance is always higher on machinery (compressors, air seals, etc.) than on pieces (compressors, air seals, etc.) than on pieces of steel (like counterweights).of steel (like counterweights).

Air Balanced UnitsAir Balanced Units

�� it is easier to adjust the air pressure for it is easier to adjust the air pressure for balancing a jack than it is to move balancing a jack than it is to move counterweights on a conventional unit.counterweights on a conventional unit.

�� Care must be taken to ensure that no Care must be taken to ensure that no hydrocarbons enter the air cylinder because hydrocarbons enter the air cylinder because an explosive mixture can result. an explosive mixture can result.

�� The air compressor suction point should The air compressor suction point should therefore be located at a point which therefore be located at a point which prevents this.prevents this.

AIR BALANCEDAIR BALANCED

�� it is also a class three lever system, it is also a class three lever system,

�� It differs from the Mark II in the method of It differs from the Mark II in the method of counterbalance. counterbalance.

Air Balance unitAir Balance unit

�� The Air Balance unit is the only beam The Air Balance unit is the only beam pumping unit which lends itself to automatic pumping unit which lends itself to automatic counterbalance. counterbalance.

�� There is available today an electronic "Black There is available today an electronic "Black Box" which is capable of sensing torque Box" which is capable of sensing torque unbalance.unbalance.

�� The electronics correct that situation by The electronics correct that situation by turning on an air compressor to increase the turning on an air compressor to increase the air pressure in the air system or open a air pressure in the air system or open a solenoid valve to decrease the air pressure solenoid valve to decrease the air pressure in the air tank, thus, adjusting the in the air tank, thus, adjusting the counterbalance to an optimum.counterbalance to an optimum.

�� The biggest disadvantageThe biggest disadvantage of the Air Balance of the Air Balance

pumping unit is that it required routine pumping unit is that it required routine

proper maintenance. proper maintenance.

�� The Air Balance method of counterbalance The Air Balance method of counterbalance

permits the manufacture of the worlds permits the manufacture of the worlds

largest beam and sucker rod pumping unit largest beam and sucker rod pumping unit

in the Air Balance Ain the Air Balance A--25602560--470470--240.240.

Beam Balanced Pumping Beam Balanced Pumping

Unit Unit

Beam Balanced Pumping Beam Balanced Pumping

UnitUnit

�� The counterweights are placed on The counterweights are placed on

the walking beam on this unit. the walking beam on this unit.

�� The largest beam balance unit is a The largest beam balance unit is a

5757--109109--48 so it is used on shallow 48 so it is used on shallow

low productivity wells low productivity wells

Low Profile pumping unit Low Profile pumping unit

CONVENTIONAL PORTABLECONVENTIONAL PORTABLE

�� is an entirely self contained pumping is an entirely self contained pumping

unit, mounted on its own integral unit, mounted on its own integral

trailer trailer

�� These units are available in sizes These units are available in sizes

varying from a CMvarying from a CM--160D160D--173173--74 74

through a CMthrough a CM--456D456D--305305--120.120.

CONVENTIONAL PORTABLECONVENTIONAL PORTABLE

STRUCTURESSTRUCTURES

For the purpose of the following discussion, we will divide the beam

pumping unit into the structural components and the gearbox

components.

The structural components are, in general, made up of

•horsehead,

•walking beam,

•samson post,

• equalizer,

•pitmans,

•unit base, and

•prime mover base.

HorseheadHorsehead

•The function of the horsehead, is to allow the pumping unit to

pull the polished rod vertically through the center of the well

head

•There are a number of ways of attaching the horsehead to the

walking beam .

• As an additional safety feature, most pumping unit

manufactures provide a safety bar that also attaches the

horsehead to the walking beam.

•The safety bar prevents the horsehead from falling off the

walking beam during those instances when the well load is not

attached to the horsehead or during a high rod part that could

throw the horsehead off the walking beam and perhaps injure

someone.

HorseheadHorsehead

CRANK PIN BEARING CRANK PIN BEARING

ASSEMBLYASSEMBLY

crank pin bearing assembly

a crank pin bearing assembly is made up of a

•tapered crank pin,

•bearing housing and seal,

•a double row spherical bearing

•The crank pin is tapered so that it can be fit into a

matching taper on the crank to allow for a fit between the crank and the pin that is both tight and, yet, relatively easy to disassemble to allow for stroke changing.

• It is extremely important that the taper on the crank pin as well as the taper in the crank be the same

equalizer bearing assembly equalizer bearing assembly

componentscomponents

equalizer bearing assembly equalizer bearing assembly

components components

Center Bearing For a Center Bearing For a

Conventional Pumping Unit Conventional Pumping Unit

GEAR TRANSMISSIONGEAR TRANSMISSION

•It is the more complex and vital parts of the pumping unit is the gear transmission.

•Because of its complexity, the transmission represents approximately 50% of the manufacturing cost of the pumping unit.

•The purpose of a gear reduction unit is to both reduce the speed of the prime mover to the desired pumping speed

COMMON GEAR TYPESCOMMON GEAR TYPES

•The gearing used in pumping units is divided into two types. For the larger gearing (40 API rating and larger), the herringbone gear design dominates. The smaller, less

expensive, lighter duty pumping unit usually uses the single helical design

WHERE:

SPM = PUMPING SPEED

R = GEAR RATIO

RPM = MOTOR SPEED

d = DIA- OF SMALL SHEAVE. IN

D = DIA-OF LARGE SHEAVE, IN

TORQUETORQUE

�� Torque is expressed as "distance x force" and Torque is expressed as "distance x force" and the accepted units for gearbox torque are the accepted units for gearbox torque are inch pounds. inch pounds.

�� In other words, the torque on a given In other words, the torque on a given gearbox will be the result of what forces the gearbox will be the result of what forces the crank arm sees multiplied by the length of crank arm sees multiplied by the length of the force arms doing the work.the force arms doing the work.

�� ..

TORQUETORQUE

�� The gearbox torque consists of The gearbox torque consists of

two components. two components.

–– One is the force created by the One is the force created by the

well load andwell load and

–– the other is the force created by the other is the force created by

the counterweights, crank arms the counterweights, crank arms

and unit imbalanceand unit imbalance

By formula Torque can By formula Torque can

be expressed as be expressed as

Gear box torque = well load Gear box torque = well load

torque torque -- counterbalance counterbalance

torquetorque

TORQUETORQUE

Unit loading and gearbox torque will be Unit loading and gearbox torque will be

altered as a result of any of the following altered as a result of any of the following

condition changes:condition changes:

�� Bottom hole pump size.Bottom hole pump size.

�� Unit speed (SPM).Unit speed (SPM).

�� Counterbalance adjustment.Counterbalance adjustment.

�� Fluid level (Fluid level (downholedownhole).).

�� Flow line pressure.Flow line pressure.

�� Unit stroke length.Unit stroke length.

TORQUETORQUE

GEAR BOX TORQUEGEAR BOX TORQUE

�� Gearbox torque is the Gearbox torque is the

instantaneous torque for a given instantaneous torque for a given

crank angle displayed in crank angle displayed in

thousands of inch pounds. thousands of inch pounds.

* Indicates Maximum Torque.* Indicates Maximum Torque.

18752187527833778337--6067260672195.0195.0

18349183494182741827--5646556465210.0210.0

1956419564320343203417831783225.0225.0

204752047527579275798028080280240.0240.0

21404214042521425214168552168552255.0255.0

20799207992389523895186875186875* 270.0* 270.0

19917199172319223192178194178194285.0285.0

18518185182298822988138266138266300.0300.0

17484174842348023480109922109922315.0315.0

167771677725546255468780387803330.0330.0

162701627033417334176073060730345.0345.0

154911549120890220890222947229470.00.0

Actual LoadActual LoadPermissible Permissible

LoadLoadTorqueTorqueCrank AngleCrank Angle

UPSTROKEUPSTROKE

Torque Calculations for Conventional Unit Counterbalance Effect Torque Calculations for Conventional Unit Counterbalance Effect = =

17207 Pounds 17207 Pounds

Gear Box Rating of 320000 InchGear Box Rating of 320000 Inch--PoundsPounds

* Indicates Maximum Torque.* Indicates Maximum Torque.

1498814988--1045210452--107501075015.015.0

148301483013751375--363183631830.030.0

150591505950015001--493904939045.045.0

151881518869736973--280582805860.060.0

174311743183878387--7286572865*75.0*75.0

185681856894119411--558525585290.090.0

18456184569869986963046304105.0105.0

1843618436935593553933739337120.0120.0

1841918419717071704223542235135.0135.0

1869118691176417641511315113150.0150.0

1877418774--1278212782--1857318573165.0165.0

1877018770--121257121257--4786647866180.0180.0

Actual LoadActual LoadPermissible Permissible

LoadLoadTorqueTorqueCrank AngleCrank Angle

DOWNSTROKEDOWNSTROKE

Maximum Torque

When Counterbalanced 112714 112714

CBE Required toCounterbalance Unit 19133 19133

If the counterbalance effect is increased to 19 133 from 17 207 inch pounds then the unit would be in balance and the peak torque would be reduced to 112 714 inch

pounds.

، ، " " How fast can I run my How fast can I run my

pumping unitpumping unit ؟ ؟ ""

Since the pumping unit is connected to the polished rod through a flexible wire line, it cannot push the rods into the well. The limiting speed of the pumping unit is set by the fall of the rods into the well, and the fall of the rods into the well is set by the retarding forces in the well. Some of those forces are:

A. Friction from the stuffing boxB. Piston/Coupling effectC. Friction between the rods and the tubingD. Friction between the pump plunger and pump barrelE. Friction of fluid on the rods

PUMPJACK SIZE DETERMINATION

A pumping system has to be properly designed taking into consideration all the variables.

These variables include:

•Potential well productivity.•Well depth.

•Pump size.•Pumping speed.•Fluid viscosity.

•Sucker rod and tubing size etc