Pump Sizing

Example 1

Pump Sizing Procedure(High Water cut well)

1. Collect data (well, production, fluid, electrical)

2. Determine the production capacity of the well

3. Calculate Total Dynamic Head (TDH) and determine tubing size

4. Select pump stage type

5. Calculate the number of pump stages required

6. Check pump shaft loading and pump

housing pressure

Pump Sizing Procedure(High Water cut well)

7. Calculate motor horsepower requirements and select a suitable motor

8. Calculate the protector thrust bearing load

and select a suitable protector

9. Determine the correct cable size and select a

suitable cable type.

10. Calculate the surface voltage and KVA

requirements and select a suitable switchboard

and transformer

1. Collect Data

• Casing size

• Perforation depth

• S.G. of produced fluid

• Tubing sizes available

• Pump setting depth

• Static Fluid Level

• Productivity Index

• Bottom Hole Temperature

• Wellhead Pressure required

• Desired Flowrate

1. Collect Data

• Casing size 5.5 inch

• Perforation depth 6000 ft.

• S.G. of produced fluid 1.0

• Tubing sizes available 2 3/8 inch

• Pump setting depth 5500 ft

• Static Fluid Level 1820 ft

• Productivity Index 0.9 BPD/psi

• Bottom Hole Temperature 260 deg F

• Wellhead Pressure reqd. 100 psi

• Desired Flowrate 1300 BPD

2. Determine the production Capacity of the well

• Flowing fluid level = Static fluid level + Drawdown

• Max Drawdown possible = 6000 ft – 1820 = 4180 ft.

• Max Drawdown (psi) = 4180 x 0.433 psi/ft = 1810 psi

(Gradient = 0.433x S.G.)

• Maximum possible flow (drawing fluid right down to the perforations = 1810 psi x 0.9 BPD/psi =

1629 BPD

3. Calculate TDH @ 1300 BPD

• Flowing Fluid Level @ 1300 BPD = SFL + DD

• Draw Down (psi) = 1300 BPD/ 0.9 BPD/psi = 1444 psi

• Draw Down (feet) = 1444 psi/ .433 psi/ft = 3335

ft.

• Flowing Fluid Level = 1820 ft + 3335 ft = 5155 ft

• Friction Loss = 31 ft per 1k ft x 5500 ft = 171 ft

3. Calculate TDH @ 1300 BPD (cont.)

• WHP = 100 psi / 0.433 psi/ft = 231 ft.

• Total Dynamic Head = Static Lift + WHP + Friction

TDH = 5155 + 231 + 171 = 5557 Ft

4. Select Pumps Stage type

• Select a pump suitable for installation in 5.5 inch casing and also capable of

producing 1300 BPD

Select a DN1300

5. Calculate the number of stages required

• At 1300 BPD the DN 13000 generates 20.4 ft per stage

(please review the DN1300 curve in the catalog)

• Number of stages required = 5557 ft/ 20.4 ft per

stage

= 272 stages

• Utilising the next standard Housing size = 276 stages

6. Check shaft loading and Housing Pressure limitations

• Pump Hp = .315 HP/stage x 276 x 1.0 (SG) = 87 HP

• Maximum shaft HP rating = 125 HP (see curve)

• Therefore the standard shaft is O.K.

• Maximum head in operating range =24 X 276 =

6624 ft.

• Maximum pressure in range = 6624 ft x .433 = 2868 psi

• Housing pressure rating = 5000 psi (see curve)

• Therefore the housing is O.K

7. Select Motor

• Motor HP required = pump HP = 87 HP

• Select a motor suitable for installation in 5.5 inch well

Therefore select a 456 series motor (4.56 inch

O.D.)

• Select a 456 series 100 HP, 1350 volt, 50 amp Intermediate motor (Remember BHT = 260

deg F)

8. Calculate Protector thrust bearing load and choose protector type

• Maximum pressure in operating range = 2868 psi

Cross sectional area of Pump shaft = 0.371 sq. in.

• TB load for floater pumps = 2868 psi x .371 sq. in =1064 lbs

• Select Bronze Bearing bearing rated at 3750 lbs @

260 deg F (information in protector section of catalog)

9 Determine cable size

• Motor is rated 100 HP, 60 HZ. , 50 Amp

• Pump Load is 87 HP

• Motor operating current = 87/100 x 50 = 43.5 amp.

• Choose a cable size with a volts drop < 30v/1000

ft

• Choose No 4 AWG cable

Calculate Surface voltage and size switchboard and transformer

• Voltage drop at 43.5 amps = 18.6 volts/1000 ft

• We have 5600 ft of cable allowing for 100 ft at surface

• Voltage drop = 5.6 x 18.6 = 104 volts

• Surface Voltage required = 1350 (motor) +104 =

1454 v.

Calculate Surface voltage and size switchboard and transformer (cont.)

• Surface Voltage required = 1350 (motor) +104 = 1454 v.

• Therefore use a 1500 volt rated Switchboard.

• Surface KVA = 1454 (volts) x 43.5 (amps) x 1.73 = 110 KVA

1000

• Therefore use a 125 KVA 3 phase dual wound

transformer with Multi tapped secondary

Pump Sizing

Example 2

Pump Sizing Procedure(High Water cut well)

• 1. Collect data (well, production, fluid, electrical)

• 2. Determine the production capacity of the well

• 3. Calculate Total Dynamic Head (TDH) and determine tubing size

• 4. Select pump stage type

• 5. Calculate the number of pump stages

required

• 6. Check pump shaft loading and pump housing pressure

Pump Sizing Procedure(High Water cut well)

• 7. Calculate motor horsepower requirements and select a suitable motor

• 8. Calculate the protector thrust bearing load

and select a suitable protector

• 9. Determine the correct cable size and select a suitable cable type.

• 10. Calculate the surface voltage and KVA

requirements and select a suitable switchboard and transformer

1. Collect Data

• Casing size

• Perforation depth

• S.G. of produced fluid

• Tubing sizes available

• Pump setting depth

• Static Fluid Level

• Productivity Index

• Bottom Hole Temperature

• Wellhead Pressure required

• Desired Flowrate

1. Collect Data

• Casing size 7.0 inch

• Perforation depth 5000 ft.

• S.G. of produced fluid ?

• Tubing sizes available 3.5 inch OD EUE, 9.3 LB.

• Pump setting depth ? ft

• Static Fluid Level ?

• Static Bottom Hole Pressure 2000 psi

Oil Cut 30 %

• Water S.G. 1.05

• Oil API Gravity 30

1. Collect Data

• Productivity Index 3.5 BPD/psi

• Bottom Hole Temperature 250 deg F

• Wellhead Pressure reqd. 50 psi

• Desired Flowrate 6000 BPD

We have an Oil and Water mixture

• In this example we have a mixture of oil and water

• Therefore we need to calculate an average SG

for the fluid mixture.

• Ave S.G. = ((0.7 x 1.05) + (0.3 x 0.876))

= 0.735 + 0.263 = 0.998

• Fluid Gradient = 0.433

We also have to calculate the Static Fluid Level

• What do we know to help us

• 1. Fluid Gradient = 0.433 as we have just calculated

• 2. SBHP – which has been given at the depth of

5000 ft.

Calculating the Static Fluid Level

SBHP = 2000

psi

Surface

Static Fluid level

2000 / 0.433 = 4619

ft

5000 ft

381 ft

@

2. Determine the production Capacity of the well

• Flowing fluid level = Static fluid level + Drawdown

• Max Drawdown possible = 5000 ft – 381= 4619 ft.

• Max Drawdown (psi) = 4619 x 0.433 psi/ft = 2000 psi

(Gradient = 0.433x S.G.)

• Maximum possible flow (drawing fluid right down to the perforations = 2000 psi x 3.5 BPD/psi =

7000 BPD

3. Calculate TDH @ 6000 BPD

• Flowing Fluid Level @ 6000 BPD = SFL + DD

• Draw Down (psi) = 6000 BPD/ 3.5 BPD/psi = 1714 psi

• Draw Down (feet) = 1714 psi/ .433 psi/ft = 3958

ft.

• Flowing Fluid Level = 381ft + 3958 ft = 4339 ft

• Friction Loss = 100 ft per 1k ft x 4841 ft = 484 ft

3. Calculate TDH @ 6000 BPD (cont.)

• WHP = 50 psi / 0.433 psi/ft = 115 ft.

• Total Dynamic Head = Static Lift + WHP + Friction

TDH = 4339 + 115 + 484 = 4938 Ft

4. Select Pumps Stage type

• Select a pump suitable for installation in 7.00 inch casing and also capable of

producing 600 BPD

Select a GN 5600

5. Calculate the number of stages required

• At 6000BPD the GN 5600 generates 28 ft per stage

(please review the GN 5600 curve in the catalog)

• Number of stages required = 4938 ft/ 28 ft per

stage

= 176 stages

• Utilising the next standard Housing sizes

• Select 2 x 68 stg housings and 1 x 40 stg = 176 stages

6. Check shaft loading and Housing Pressure limitations

• Pump Hp = 1.8 HP/stage x 176 x 1.0 (SG) = 316.9 HP

• Maximum shaft HP rating = 375 HP (see curve)

• Therefore the standard shaft is O.K.

• Maximum head in operating range = 34 X 176 =

5984 ft.

• Maximum pressure in range = 5984 ft x .433 = 2591 psi

• Housing pressure rating = 5000 psi (see curve)

• Therefore the housing is O.K

7. Select Motor

• Motor HP required = pump HP = 316.8 HP

• Select a motor suitable for installation in 7.0 inch well

Therefore select a 540 series motor (5.43 inch

O.D.)

(either a SX or SK (formerly 90-0) type desired depending upon insulation type required))

• Select a 540 series 350 HP, 4400 volt, 48 amp

Tandem motor made up of 1 x UT motor and 1

x CT motor – each 2220 volt, 48 amp sections. A UMB is required.

8. Calculate Protector thrust bearing load and choose protector type

• Maximum pressure in operating range = 2591 psi

Cross sectional area of Pump shaft = 0.785 sq. in.

• TB load for floater pumps = 2591 psi x 0.785 sq. in =2033 lbs

• Select standard Bronze bearing rated at 9000 lbs

@ 250 deg F

(information in protector section of catalog)

9 Determine cable size

• Motor is rated 350 HP, 60 HZ. 4400 v , 48 Amp

• Pump Load is 316.8 HP

• Motor operating current = 316.8/350 x 48 = 43.5amp.

• Choose a cable size with a volts drop < 30v/1000

ft

• Choose No 4 AWG cable

Calculate Surface voltage and size switchboard and transformer

• Voltage drop at 43.5 amps = 18.6 volts/1000 ft

• We have 4941 ft of cable allowing for 100 ft at surface

• Voltage drop = 4.94 x 18.6 = 71.8 volts

• Surface Voltage required = 4400 (motor) +72 =

4472 v.

Calculate Surface voltage and size switchboard and transformer (cont.)

• Surface Voltage required = 4400 (motor) +72 = 4472 v.

• Therefore use a Non Standard volt rated Switchboard as

• The 1512 and the RPR2 boards are 3900 volts max.

• Surface KVA = 4472 (volts) x 43.5 (amps) x 1.73 = 337 KVA

1000

• Therefore use a 400 KVA 3 phase dual wound

transformer - with multi tapped secondary

Something tothink about with this sizing

As the motor selected resulted in us having to purchase

a non standard switchboard and transformer, which

may be very expensive we may wish to review the

motor selection .

We could choose to use a tandem 175 HP, 1350 v 78.5 amp

Motor , that is a 350 HP, 2700v, 78.5 amp motor

instead,

If we did so we would have to reselect the cable, and

surface equipment.