3. Modelo de Influjo Complejo

7/28/2019 3. Modelo de Influjo Complejo

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EX 3 1Example 3

FloSystem User Course

Complex Inflow Modelling


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EX 3 2Complex Inflow

Wellflo Inflow models :

Vertical or Horizontal wells.

Multiple layers or compartments (up to 36) each withits own water cut and GOR.

Skin effects of damage, perforations, deviation,partial penetration, gravel packs and fractured wells.

Flow models include normalised pseudo pressure,accounting for relative permeability effects, as wellas simpler Straight line, Vogel and Fetkovitchmodels


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EX 3 3Skin Analysis

Load EXAMPL3A.WFL

This models a single high permeability layer whereconing might be a problem, the example looks at the

effect of increasing the perforated interval.

Double Click on the reservoir node.

Note that only one of the five layers is active.

Note layer is 27ft thick.

Select Edit Layer - Skin Analysis - Model.

The Limited Entry Skin is the section we willexamine.


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EX 3 4Skin Analysis

Total skin is nearly 4 with only 7ft perforated inthe well.

Select OK until you return to the Icon display.

Select Analysis - Operat ing Point.

Select Calculateand then Resultsand Plottosee the Inflow Outflow Curves including thecurve showing the pressure drop across across

the completion. Note that the Pressure Drop across the

completion (lower curve displayed) is onlyavailable for single layer IPRs.


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EX 3 5Skin Analysis

1

2

3

4

A

B


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EX 3 6Skin Analysis

Return to Nodal Analysis and select Sensit iv i t ies.

Select Open Intervalas Sens it iv i ty 1

Editusing the values 2ft, 5ft , 7ft and 10ft.

Return to Nodal Analysis window and switch onSens it iv i ty 1.

Select Calculateand view the Inflow/OutFlow curveswith All Valuesset on Sens it iv i ty 1.

View the Performance Analysis Plot.

What is the optimum perforated thickness (from thevalues given)?


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EX 3 7Skin Analysis

Load EXAMPL3B.WFL

This example models a fractured well and the effectof increasing the fracture half length and the fracture

width.

Look at Reservoir Control - Edit layer - Skin Analysis- Model.

Note that the other options for skin are not allowed

for a fractured well as the model assumes the inflowis dominated by the fracture behaviour itself

Note that infinite conductivity and finite conductivityfractures can be modelled including the conductivityof the proppant.


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EX 3 8Skin Analysis

Return to the Icon display and select Analys is -Operating Poin t - Sens it ivi t ies...

Select Fracture Half Length as Sens it iv i ty 1

EditSensitivity 1 with the values 100ft, 200ft, 300ft, 400ft,500ft and 600ft

Return to Nodal Analysis.

Switch on Sens it iv i ty 1and Calculate.

Select Resultsand Plot.

Examine the Inflow / Outflow and PerformanceAnalysis plots.


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EX 3 9Skin Analysis

Select Fracture Width as Sens it iv i ty 2

Edit Sensit iv i ty 2with the values 0.1in, 0.12in, 0.14in and0.15in

Return to Nodal Analysis and switch on bothSens it iv i ty 2and Sens it iv i ty 1and the run Calculate

Examine the Inflow/Outflow plots and thePerformance Analysis plots.

Note the relative effects of the fracture half lengthand width.

What is the optimum combination ?


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Normalised Pseudo Pressure.

Constant mass inflow model correctly accountingfor :-

Variation of fluid properties with pressure

Accurately represents relative permeability behaviour

w

wrw

o

or o

reff

p

p g

gr g

w

wrw

o

or o

reff

KKC

dp

KKK

C)p(

01


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Normalised Pseudo Pressure

Slight difference in inflow above Pb due to higher fluidmobility.

Below Pb will accurately honour relative permeabilitycurves in Corey Coefficients or Tables - allows reservoirsimulator curves to be used directly in well modelling.

Important application in condensate wells where liquiddropout is modelled and in solution gas drive.

This can be used to accurately model three phase inflow -this has been calibrated against detailed numericalcompositional simulation and found to agree well.


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Oil/Water Relative Permeabilities for M=3.5,n=2

0

0.10.2

0.3

0.4

0.50.6

0.7

0 0.2 0.4 0.6 0.8

Sw (fraction)

Krwo

rKro


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Select OK, Choose IPR..., Normalised PseudoPressure and Plot.

Minimise the graphing window, Select Vogel, Plot

and double click on the graph icon.

Note the difference between the curves abovebubble point as well as below bubble point.

Minimise the graph again, return to the relative

permeability section and change the m and nparameters for Gas-Oil to 1.

Return to the Choose IPR... screen and selectNormalised Pseudo Pressure and Plot - note thethird curve on the Inflow plot.


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Multi-layer Modelling

Load EXAMPL3A.WFL - make all layers activeafter double-clicking on the reservoir

Select Display Composite IPRto display thetotal IPR from all layers (select water cut asadditional curve)

Note the option to plot phase components(IPR) is only available for single layer systems

(certain sensitivity variables are alsounavailable for multi-layer systems)

Return to Fluid Parameters and changeTarbert layer water cut to 90%

Display Composite IPR


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EX 3 16Conclusion

Wellflos Inflow model allows detailed analysis ofSkin effects in single and multilayer systems

Different completions in different layers and

sophisticated analytical Inflow models allow detailedrepresentation of multiphase inflow

All of the above can be modelled with ESPs, gas liftor naturally flowing wells

3. Modelo de Influjo Complejo

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