7. Wellflo - ESP Design and Analysis

7/22/2019 7. Wellflo - ESP Design and Analysis

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Example 7

FloSystem User Course

ESP Design and Analysis


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ESP Design and

Analysis Modes

Design Mode

Entering a Setting depth, max. OD, Op. frequency, Wear factors and

Efficiency.

A selection of the Pump/Motor is made

Selection is made from a internal database of five manufacturers dataAnalysis Mode

The Pump/Motor (ESP) has been selected

Performance of the ESP can be analysed running sensitivities :

Pump variables e.g. Operating Frequency

Reservoir parameters e.g. Water cut


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ESP Design Mode

Open ESP.WFL - Review Reservoir, Deviation, and Equipment Data

The completion string contains an ESP at the bottom of the tubing (i.e. 14632 ft)

Select Data Preparation - ESP Data...

Revise the Pump Environment box :

Note the Measured depth is the pump depth

OD and ID are chosen considering the casing ID

Operating frequency is a typical value

Upstream temperature used only in manual mode calculations (leave as

default)


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ESP Data... :

Design Mode only


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ESP Data... :

Design Mode only

Revise the values of Wear factors/Efficiencybox

Note the wear factor are set to 1 for the pump and

motor (i.e. no wear assumed)

The efficiency of the gas separator is 100% i.e. nofree gas through the pump

Revise the Calculations options box

The viscosity and gassiness are switched on

TheAnalysis equipmentbox can not be edited in

this mode


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ESP Design... :


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ESP Design Rate :

Liq. = 450 stb/day Select Analysis - Operating Point...

Select Calculate, Results and Plot

Note Operating Pressure = 3547 psia and Liquid rate = 110 stb/day

(very low for this well)

SelectAnalysis - Pressure Drop

select Edit Rates... and set the design rate of 450 stb/day. Select

calculate, results and plot

note that the pressure at pump depth is 3226 psia

Select Analysis - ESP Design...

Note the Design liquid rateis set at 450 stb/day

Verify with Choose ESP...that the list is empty

Revise the Correlations...options


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ESP Design... Box

Select Calculateand then Choose ESP...


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ESP Design:

Choose Pump

Revise the suitable list of Pump - Motor

Choose Pump T4-500, motor T5 Series from

manufacturer ESP Inc. and Cable #2

Select Plot toobtain the ESP performance


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ESP Pump Performance


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ESP Optimisation Pump Performance

Select Optimise... to optimise theconfiguration in terms of

Frequency,

Number of stages or

Three performance criteria (minimum,

maximum flowrate, or most efficient operating

point)Cable size powerlosses will be included

in the Electrical Powerresults


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Frequency: design calculations repeated to obtainoptimum number of stages and flowrate

Number of Stages: the new operating frequency is

estimated by reiteration (equations not shown)

Performance: the operating frequency and number

of stages are computed by iteration such that the

operating rate (P and T from mid-point of pump

depth) corresponds to the minimum, maximum orbest efficiency value


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As exercise optimise using the followingparameters:

70 Hz

reduce the number of stages to 103

change the performance to best efficiency

Review the impact of these changes on other

design parameters

ESP D i


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ESP DesignInstall...

ESP A l i


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ESP Analysis

Mode

Note that the switch Design mode only is

switched off indicating that the Analysis

modeis on

TheAnalysis equipmentbox is now editable

and displays the pump and motor parameters

installed

Select OK if satisfied with pump selected. SelectAnalysis - Operating Point (Edit rates -

Fill)

Note that the new Operating Pressure is 3240


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ESP Analysis

ESP Analysis:


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ESP Analysis:

Sensitivity Studies

Once optimum parameters: Setting depth, Tubingsize, FHTP and a Pump/Motor has been selected

Check sensitivity to

Changing Reservoir Pressure

Increasing watercut

Check Sensitivity to

Increase no of stages to increase flexibility if requiredOperating frequency

ESP A l i O


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ESP Analysis: Op.

Frequency (VFD)

Return toAnalysis - Operating Pointand selectSensitivities...

Note that Sensitivity 2 is set to Operating

frequency with values: 30, 45, 60, 75 and 90 Hz


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ESP VFD Sensitivity


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ESP VFD Sensitivity

minimum rate

maximum rate

best efficiency

rate


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WaterCut

Sensitivity Return toAnalysis - Operating pointand select

Sensitivities...

Note that sensitivity one is set to water cut with

values : 0, 25, 50, 75, 99 %


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WaterCut

sensitivity

0 % Water cut

99% Water cut

ESP & Simulation


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ESP & Simulation

VFP Tables

After all sensitivity runs have been done select Analysis - Export VFP

file... to input VFP tables to a simulator. Following are typical

requirements:

Rate FTHP w.c. GOR Frequency

b/d psia frac MSc/bbl Hz

100 50 0.0 0.49 30200 100 0.1 45

300 200 0.25 60

500 300 0.5 75

750 500 0.75 90

1000 750 0.99

6 x 6 x 6 x 1 x 5 = 1080 runs

ESP Design:


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ESP Design:

Manual Intervention

Manual Calculations required for :

Packer Selection

Protector Design

Tubing Stresses

Junction Box, transformers, switchboard

Documents

7. Wellflo - ESP Design and Analysis