FE Halliburton

Study of Feedback Controlled Variable

Cone Expansion Process

Prepared for presentation at the

2013 SIMULIA Community Conference

Allan Zhong

John Gano

2/26

Outline

1. Background

2. Preliminaries

3. The FEA model

4. Friction effect on variable cone expansion process

5. Conclusions and remarks

6. Acknowledgement

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Background

Why do we expand pipes?

Open Hole Completion - Expandable screen for sand control

Liner Hanger - Expandable liner hanger

Ref: SPE 101538 Unique Expandable Sand Screen and Expandable Liner Hanger for Saudi Aramco

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Background (continued) What is Variable Cone Expansion?

It is a process that is realized through a two-cone expansion

system with a smaller sized, fixed cone at the front and a variable

cone at the back. The variable cone can be moved between an

expanded position and a retracted position. During expansion, the

variable cone is enlarged to its expanded position and advanced

through the casing until a restriction (e.g. smaller ID wellbore

outside the casing) is reached.

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Background (continued) Feedback Control System

Assume the load on variable cone is F1, then the load on the wedge F2

is related to the F1 in the following way

F2=m F1 when F1 < F_max kips

F2= F_min when F_max < F1

The movement of the variable cone is controlled by a feedback control

system. The hydraulic feedback control process can simply be

described as the force applied on the wedge, controlled by the force

acted on the cone system.

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Background (continued) Why Variable Cone Expansion?

To allow expansion through restrictions without incurring large force

The technology also enables robust performance of expandable liner hanger

Background (continued) Simulation of Variable Cone Expansion

7/26

From numerical simulation point of view, a key feature of the

expansion process is that the force on wedge is dependent of the

force on variable cone. In other words, the load on wedge is feed

back controlled. This type load could not be applied in Abaqus

until a couple of years ago.

To simulate the variable cone expansion, a user defined sensor

can be used.

Note: This work was performed before a user defined sensor was available in

Abaqus, and a user element was developed to achieve the feedback control.

Objectives of This Study

1) Determination of critical friction coefficient

2) Study the influence of friction coefficients

between cone and pipe, and wedge and variable

3) Improve design to prevent self locking

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Preliminary Critical Friction Coefficient

Critical Friction Concept

sincos FF

tanc

Note: The critical friction

coefficient is a structural

property. In this example, the

larger the angle , the larger

the critical friction

coefficient is.

Preliminary Verification of Feedback Control

The verification is performed on a

very simple model with two separate

rectangular blocks: the force on one

block F1, is applied, the controlled

force F2 is applied on the other block.

The control scheme is:

F1= 0 to F_max lb

F2= m*F1 if F1< F_max lb

F2= F0 if F1 >= F_max lb

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Preliminary Verification of Feedback Control (continued)

The blue curve is the active load; the brown curve is the controlled force. There is a

delay in controlled force magnitude. The controlled force varies as specified per the

control scheme except it has a time delayed response. The delay, of course, is expected

for a hydraulic controller. It is noted that the delay can be reduced by a decreased time

increment in the FEA model. 11/26

FEA Model for Variable Cone Expansion

Simplified variable cone - shown one branch only

12/26

FEA Model for Variable Cone Expansion

(continued)

To simulate the loading conditions efficiently:

1) The variable cone is fixed axially by a rigid surface but can

move radially

2) The active load is the force pulling the casing

3) The wedge is pushed under the controlled load

casing

Fixed cone

Variable cone

wedge

F1

F2

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Critical Friction Coefficient for

the Base Design

The critical friction coefficient is determined straight forward, the

wedge/cone friction coefficient is varied from low to high to see when

a variable cannot reach its fully expanded position (i.e. 8 OD)

cone/pipe friction coefficient 0.05

Wedge/cone, cone/cone COF =0.2

Variable cone reached fully expanded state

7.10 7 deg cone expansion at different friction


the Base Design (continued)

cone/pipe friction coefficient 0.05

Wedge/cone, cone/cone COF =0.25

Variable cone did not reach fully expanded state - this leads to

under expansion

7.10 7 deg cone expansion at different friction

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the Base Design (continued)

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The higher the friction the slower the

variable cone reaches 8 OD. At the critical

friction coefficient it will take very long time

for the cone to reach 8

For this case critical friction is ~ 0.2

0.150.2

0.25

7.10 7 deg cone - other friction coefficient

Wedge/cone 0.2, cone/pipe 0.05

Wedge/cone 0.2, cone/pipe 0.03

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Critical wedge/cone friction depends on cone/pipe friction coefficient

Factors that Influence Critical Friction

Coefficient

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7.10 OD X 7 DEGREE X 1.32 RATIO

pipe

0.07 0.05 0.03

critical

0.05 YES NO

0.10 yes

0.15 yes yes

0.20 yes no

0.25 no

0.30

0.35

0.40

0.50

7.10 OD X 7 DEGREE X 1.869 RATIO

pipe

0.07 0.05 0.03

critical

0.05 YES NO

0.10

0.15

0.20

0.25 yes

0.30 yes

0.35 no

0.40

0.50

Increase of load ratio from 1.32 to 1.869 leads ~ 100% increase of critical

friction coefficient, from ~ 0.15 to ~ 0.3

7.10 7 deg cone - load ratio


Coefficient (continued)

Cone/pipe friction 0.03

Critical friction ~ 0.225

7.10 10 deg cone - change fix cone angle


Coefficient (continued)

Increase fix cone angle increase critical friction19/26

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Critical Friction Coefficient - Design

Consideration

7.10 10 deg cone, higher load ratio

Cone/pipe friction 0.03, cone/wedge friction 0.375

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Consideration (continued)


Cone/pipe friction 0.03, cone/wedge friction 0.375

0.375 is approximately the critical friction coefficient as before,

it takes a long stroke for the variable cone to move to max OD

position under critical friction

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Consideration (continued)


7.25 OD X 10 DEG X 1.32 RATIO

pipe

0.03

critical

0.05 yes

0.10 yes

0.15 yes

0.20 yes

0.225 yes

0.25 no

0.30 no

0.40 no

0.50

7.25 OD X 10 DEG X 1.82 RATIO

pipe

0.03

critical

0.05

0.10

0.15

0.20

0.25

0.30 yes

0.375 yes

0.40 no

0.50 no

Critical friction coefficient increased to 0.375

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System Integration Test Observations when variable cone OD

reached 8, pipe OD is 8.75 (8+2*0.375, pipe wall thickness is

0.375) - the final design met all performance requirements

Summary and Concluding Remarks

O.D. - JOINTS 1, 2, & 3

7

7.25

7.5

7.75

8

8.25

8.5

8.75

9

0 10 20 30 40 50 60

SCREENSCONNECTION CONNECTION


(continued)

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1. The method developed for simulation of feedback controlled load is verified

to function as designed.

2. The method is successfully applied to determine critical friction coefficient

for two fixed cone designs under different scenarios.

3. The critical friction coefficient between production cone and wedge is

between 0.2 and 0.25 for cone/pipe friction 0.05; it is between 0.15 and 0.2

for cone/pipe friction 0.03.

4. The modified fixed cone, 7.25/10 deg cone, under same conditions, would

lead to higher critical friction as expected, ~ 0.225 for cone/pipe friction 0.03

5. An effective way to increase critical friction is to increase wedge

force/expansion force ratio. It is shown that under cone/pipe friction 0.03, the

critical friction increased from 0.225 to 0.375.

6. A design with implementations of the design changes considered here was

tested successfully.

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Remarks

a. The limitation of the FEA is that how friction is

changing during the expansion process has to be assumed

currently constant friction is assumed. Pressure dependent

friction coefficient can be included in the FEA model, which

will need to develop another user subroutine.

b. Vibration of the expansion system during operation can

influence the expansion process, which is not accounted for in the

FEA model.


(continued)

Acknowledgement

The authors are grateful to

Halliburton Management

for permission to publish this work.

26/26

FE Halliburton

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