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8/12/2019 02 Pump Sizing 01
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02 Pump Sizing 01
ESP TRAINING
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2,000 bpd Pump Sizing
PUMP SIZING 01
As an Example, Let's say we have a 7" casing well with which we want to produce2000 BPD. We are told that we will need a pump with a total lift of 1850 feet. We will
have 60 Hz power available.
What do we need to do?
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2,000 bpd Pump Sizing
PUMP SIZING 01
The first thing to do is to look in the catalog to see what pumps are available whichwill produce 2000 bpd. For 60 Hz power, we will use the 3500 RPM curves.
Note: If the power were 50 Hz, we would use the 2917 RPM curves.
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2,000 bpd Pump SizingPump Selection
PUMP SIZING 01
In the catalog, we can see that we have four pumps which can produce 2000 bpdwithin the recommended operating range. They are the DN1750, DN2150, GN1600
and GN2100. Let's take a look at each of them.
(We have excluded the AN1500 for now, A series pumps are 375 series and not
appropriate for CNOOC wells)
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2,000 bpd Pump SizingPump Selection
PUMP SIZING 01
The two black lines represent the recommended operating range
DN1750 - 60 Hz
0 500 1000 1500 2000 2500 3000
0
5
10
15
20
25
30
35
Flow Rate - BPD
Head in Feet
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2,000 bpd Pump SizingPump Selection
PUMP SIZING 01
A D series pump is 4.00 inches in diameter
DN2150 - 60 Hz
0 500 1000 1500 2000 2500 3000
0
10
20
30
40
Flow Rate - BPD
Head in Feet
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2,000 bpd Pump SizingPump Selection
PUMP SIZING 01
Notice that G pumps put out more head than D pumps
GN2100 - 60 Hz
0 500 1000 1500 2000 2500 3000 350
0
10
20
30
40
50
60
Flow Rate - BPD
Head in Feet
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2,000 bpd Pump SizingPump Selection
PUMP SIZING 01
A G series pump is 5.13 inches in diameter
GN1600 - 60 Hz
0 500 1000 1500 2000 2500 300
0
10
20
30
40
50
60
Flow Rate - BPD
Head in Feet
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2,000 bpd Pump SizingPump Selection
PUMP SIZING 01
DN1750 - 60 Hz
0 500 1000 1500 2000 2500 30000
5
10
15
20
25
30
35
Flow Rate - BPD
Head in Feet
GN1600 - 60 Hz
0 500 1000 1500 2000 2500 30000
10
20
30
40
50
60
Flow Rate - BPD
Head in Feet
0 500 100
0
150
0
200
0
250
0
300
0
0
10
20
30
40
Flow Rate - BPD
Head in Feet
GN2100 - 60 Hz
0 500 1000 1500 2000 2500 3000 35000
10
20
30
40
50
60
Flow Rate - BPD
Head in Feet
DN2150 - 60 Hz
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2,000 bpd Pump SizingSizing Tips
PUMP SIZING 01
What do we do with four choices?
We could size all four and compare them but that might take more time than we
have. Consider ways to cull them before going too far.
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2,000 bpd Pump SizingSizing Tips
PUMP SIZING 01
Bigger Diameter is almost always better:
Advantages: Disadvantages:
Usually More Efficient Lower Maximum Pressure
Usually Less Expensive Can Interfere w/ Y-Tool
Better in Gas & Viscosity More Downthrust
Handles Higher Hp
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2,000 bpd Pump SizingSizing Tips
PUMP SIZING 01
Based on this, let's eliminate the DN1750 and DN2150 pumps since they are smallerdiameter.
Now compare the GN1600 and GN2100.
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2,000 bpd Pump SizingGN1600 and GN2100
PUMP SIZING 01
GN2100 - 60 Hz
0 500 1000 1500 2000 2500 3000 35000
10
20
30
40
50
60
Flow Rate - BPD
Head in Feet
GN1600 - 60 Hz
0 500 1000 1500 2000 2500 30000
10
20
30
40
50
60
Flow Rate - BPD
Head in Feet
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2,000 bpd Pump SizingGN1600 and GN2100
PUMP SIZING 01
Note that the GN1600 only supplies about 35 feet per stage while the GN2100supplies 45 feet per stage. This means that the GN2100 will take fewer stages to do
the job.
Note also that the GN2100 would be operating closer to the middle of the
recommended range which means that this pump will be more efficient.
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2,000 bpd Pump SizingGN1600 and GN2100
PUMP SIZING 01
GN1600 - 60 Hz
0 500 1000 1500 2000 2500 3000
0
1
0
2
0
3
0
4
0
5
0
6
0
Flow Rate - BPD
Head in FeetGN2100 - 60 Hz
0 500 1000 1500 2000 2500 3000
01020304050
60
Flow Rate - BPD
Head in Feet
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2,000 bpd Pump SizingGN2100
PUMP SIZING 01
The fewer stages and better efficiency will most likely mean that the GN2100 will beless expensive to purchase as well as to operate so let's use it.
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2,000 bpd Pump SizingGN2100
PUMP SIZING 01
Note the head per stage is about 45 feet.
GN2100 - 60 Hz
0 500 1000 1500 2000 2500 3000 3500102030405060
Flow Rate - BPD
Head in Feet
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2,000 bpd Pump Sizing
PUMP SIZING 01
By the way, what is a stage anyway?
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2,000 bpd Pump Sizing
PUMP SIZING 01
The centrifugal pump is made up of distinct units called stages. Each stage consistsof one impeller and one diffuser.
Note the flow direction. The impeller sends it out & the diffuser redirects it upward
Diffuser
of lower
stage
Diffuser
Impeller
Flow Flow
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2,000 bpd Pump Sizing
PUMP SIZING 01
The impeller is attached to the shaft and rotates with it. The Diffuser is stationaryinside the pump housing.
Depending on the stage type, the impeller will have about 7 to 9 curved vanes
which give a nice smooth motion to the fluid as it moves from the entrance (or eye)
of the impeller to the outside edge.
A diffuser also has vanes which curve the fluid upward. The diffuser always has a
different number of vanes than the impeller. How many vanes does it have?
Why?
To prevent vibration!
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2,000 bpd Pump Sizing
PUMP SIZING 01
Impellers come in several different types depending on the diameter and the flowrate.
ESP impellers are basically two types: radial flow (also called pancake impellers)
and mixed flow.
The type of impeller is dictated in the design process of the stage and is constrainedby how much flow and head the impeller is intended to put out as well as the
diameter it has to work with.
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Pump Stage Types
PUMP SIZING 01
Radial flow (pancake)
Francis
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Pump Stage Types
PUMP SIZING 01
Mixed Flow
Axial flow (propeller)
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2,000 bpd Pump SizingGN2100
PUMP SIZING 01
The GN2100 pump has a stage designed to produce flow at a maximum efficiency atabout 2100 BPD. The internal geometry of the stage is what controls this.
A GN1600, for example, has a different geometry and is designed to be most efficient
at about 1600 BPD.
The stage geometry controls how much flow volume can go through it. If one stageof a GN2100 will produce the 2000 BPD in our example, two stages will not produce
4000 BPD - they will still only produce 2000 BPD.
In simpler terms, flow is not additive- it is constant.
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2,000 bpd Pump SizingGN2100
PUMP SIZING 01
The head produced is a different matter. If one stage produces 45 feet, two stageswill produce 90 feet, four stages will produce 180 feet, etc.
Put simply, the head is additive. But why is this the case?
The first impeller takes the fluid and slings it outward imparting a lot of energy to the
fluid. The diffuser takes this outward motion and redirects it upwardly giving headto the fluid.
The next impeller takes this higher head fluid and again slings it outward giving it
even more energy.
The next diffuser takes this additional energy and converts it to even more head and
so on...
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2,000 bpd Pump SizingGN2100
PUMP SIZING 01
But how does this apply to our example?
Remember that we wanted a pump to give 1850 feet of head.
We now know the GN2100 we have chosen will provide 45 feet per stage.
This means we will need a 41 stage GN2100 to do the job.
Now that the hard part is over, look at the other important curve for the GN2100
which is the Brake Horsepower (BHP) curve.
4145850,1
/#
stgheadHeadStages req
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2,000 bpd Pump SizingGN2100
PUMP SIZING 01
Note that the BHP/stage is about 1.05
0 500 1000 1500 2000 2500 3000 35000.6
0.7
0.8
0.9
1.0
1.1
Flow Rate - BPD
BHP per Stage
GN2100 - 60 Hz
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2,000 bpd Pump SizingGN2100
PUMP SIZING 01
1.05 BHP/stage * 41 stages = 43 Horsepower
This means that the pump will require 43 horsepower to do the job.
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2,000 bpd Pump Sizing
PUMP SIZING 01
In Summary:
We needed to design a pump to produce 1850 feet of head at 2000 BPD.
We looked at four possible pumps and, using some simple guidelines, we eliminated
three of them.
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2,000 bpd Pump Sizing
PUMP SIZING 01
In Summary:
We ended up with a 41 stage GN2100 which will draw 43 horsepower.
That's all there is to sizing a pump.
By the way, what is the efficiency?
771,135
BHP
HeadFlowhyd
%4.63771,13543
850,1000,2
hyd
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2,000 bpd Pump SizingGN1600
PUMP SIZING 01
Now that we have mastered sizing pumps, let's go back and size the GN1600 forcomparison. In order to do this we will need to:
1) Read the head per stage
2) Calculate the number of stages required
3) Read the BHP per stage
4) Calculate the total horsepower required
5) Calculate the efficiency
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2,000 bpd Pump SizingGN1600
PUMP SIZING 01
The head per stage is about 35.5 feet
GN1600 - 60 Hz
0 500 1000 1500 2000 2500 30000
10
20
30
40
50
60
Flow Rate - BPD
Head in Feet
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2,000 bpd Pump SizingGN1600
PUMP SIZING 01
This means we will need a 52 stage GN1600 to do the job.
The GN1600 requires about 0.93 BHP/stg at 2000 BPD
0.93 BHP/stage * 52 stages = 48.5 Horsepower
This means that the pump will require 48.5 Hp to do the job.
525.35
850,1
/#
stghead
HeadStages
req
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2,000 bpd Pump SizingGN1600
PUMP SIZING 01
Calculating Efficiency:
Since the only thing in the equation which has changed is the BHP and we are nowdividing by a larger number than before, the efficiency should go down.
The efficiency is 56.2% compared to 63.4 for the GN2100
%2.56771,1355.48
850,1000,2
hyd
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Sizing Comparison
PUMP SIZING 01
For the GN1600:
For the GN2100:
As you can see, regardless of what type of pump we use, the energy required to
pump the fluid is constant
in
outhyd
WorkWork
inhydout WorkWork
HPWorkout 3.275.48562.0
HPWorkout 3.270.43634.0
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Sizing Comparison
PUMP SIZING 01
For the GN1600:
For the GN2100:
Where did it go?
We can see that, as predicted, the GN1600 is less efficient so it will require a larger
motor to be purchased as well as more electricity to run it.
Additionally it took more stages (52 compared to 41) so will probably be a more
expensive pump.
The GN2100 is a better sizing
2.213.275.48 lossesHP
7.153.270.43 lossesHP
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