test report on flexible coupling in laboratory -...

Deliverable D4.2

Test report on Flexible Coupling in laboratory

Grant agreement no. 654497

Duration 01.02.2016 – 31.01.2019

Work package WP4 – Flexible Coupling and casing materials

Type R - document, report

Dissemination level PU - public

Due date 31.08.2017

Actual submission date 30.11.2017

Lead author Hans Iver Lange (SINTEF)

Giovanni Perillo (SINTEF)

Contributors

Version 1.0

Report no.

Document status

Change history Version Date Changes

This publication was completed with the support of the European

Commission and European Union funding under Horizon 2020 research

and innovation programme. The contents of this publication do not

necessarily reflect the Commission's own position. The document reflects

only the author's views and the European Union and its institutions are

not liable for any use that may be made of the information contained here.

Innovative materials and designs for long-life high-temperature geothermal wells

SINTEF Materials and Chemistry

Materials Integrity and Welding 2017-10-16

2017:00254- Restricted

Report

Full scale testing of Flexible Coupling for geothermal casings

Mechanical integrity and leakage

Author(s) Hans Iver Lange

Giovanni Perillo

PROJECT NO. 102014946

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Document history

VERSION DATE VERSION DESCRIPTION

00 2017-07-14 Issue of report for client review

01 2017-08-18 Including corrections based on comments from Statoil. Issue of report

02 2017-08-23 Including corrections based on comments from ISOR

03 2017-10-11 Including Test 3

04 2017-10-16 Corrections after review from the client


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Table of contents 1 INTRODUCTION ............................................................................................................................. 4

2 OBJECTIVE ..................................................................................................................................... 4

3 TEST DESCRIPTION AND SETUP ...................................................................................................... 5

3.1 Simplified Test Procedure .............................................................................................................. 5

3.2 Test rig ............................................................................................................................................ 7

3.3 Instrumentation ............................................................................................................................. 8

3.4 Assembly and torque ................................................................................................................... 10

4 TEST RESULTS .............................................................................................................................. 11

4.1 Test 1 ............................................................................................................................................ 12

4.2 Test 2 ............................................................................................................................................ 16

4.3 Test 3 ............................................................................................................................................ 21

5 DISCUSSION ................................................................................................................................ 25

5.1 Limitations of leakage rate........................................................................................................... 25

5.2 Leakage rate measurement ......................................................................................................... 25

5.3 Comparisons of the final rupture loading .................................................................................... 26

6 CONCLUSIONS ............................................................................................................................. 27

7 REFERENCES ................................................................................................................................ 27

APPENDICES

Appendix A: SINTEFs practical interpretation of the Test Procedure

Appendix B: Details of the instrumentation and calibrations

Appendix C: Geometry, dimensions and fabrication of the test specimen and fixtures

Appendix D: Receipt of test material

Appendix E: Detailed results of the strain gauges


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1 INTRODUCTION

High temperature variations during operation of a geothermal well, and especially during start up and cool

down, introduces significant axial thermomechanical loadings to the casing. A method to relax the

thermomechanical loadings is to introduce an element of axial displacement in the casing. The intension of

this prototype of flexible coupling is to open for 20 mm stroke inside the coupling, and still hold the

requirements regarding mechanical integrity and leakage according to the standard ISO/PAS 12835:2013(E).

However, this standard is for none-sliding couplings, so some modifications had to be done in the Test

Procedure.

ISOR has developed the present flexible coupling, which is a prototype, and a request was received from

Statoil to perform a full-scale test program. A test procedure was developed by Statoil, based on the test

facilities at SINTEF combined with relevant parts of the referred test standard. Finally it was agreed on a

instrumentation plan and that water was used for pressurization instead of gas. The latter was a HSE

prerequisite from SINTEF, to be able to perform the tests inside the facilities of the test laboratory.

Larger leakage, compared to the threads of the coupling, were identified from the safety pins and

circumferential transition of the coupling of Test 1 and Test 2. This made it impossible to reach the required

pressure for some of the tensile test conditions due to the unsatisfactory flow rate of the pump. The leakage

rates from the threads on the sliding side of the coupling were monitored during the tests. These are close to

the maximum requirement of the referred test standard, and the leakage is expected to be even higher if water

is exchanged with vapour/gas. The test program was therefore stopped after two tests. The third test was

performed on a modified version of the coupling, and a pump with larger flow rate was used. Significantly

higher leakage was experienced from the circumferential transition of the coupling. Therefore it was decided

to reduce the content of the Test Procedure for this tests.

2 OBJECTIVE

Three full scale tests are performed on a prototype for a flexible coupling, used on 9⅝" casings. The

objective is to verify the mechanical integrity and leakage of the coupling at room temperature. The loadings

consist of tension, compression and bending combined with internal pressure, following a specific Test

Procedure, see ref. /2/.

Figure 1. Principle sketch of the test setup (see also photo in Figure 3).


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3 TEST DESCRIPTION AND SETUP

Three similar flexible couplings, developed and produced by ISOR, were received at the premises of the test

laboratory, together with threaded 9⅝" casings (1 meter long, L80 grade steel). In addition, two 12 meter

long pipes were received for extension piping to the test machine (P110 grade steel). More details of the

coupling are given in ref. /2/ and /3/. The third test was performed on a modified coupling. The intension of

the modification was to reduce the leakage from the safety pins and transition seam of the coupling.

The OD of the casing is 245mm and the WT is 12.3mm (ID 220.4mm). The OD of the extension piping is

253mm and the WT is 16mm (ID 221mm).

The intension of the test setup is to have stiffer and stronger pipes towards the flanges. This prevents plastic

deformations in the extension pipe during testing. A sketch is shown in Figure 1.

3.1 Simplified Test Procedure

The test consisted of application of axial load (tension and compression) to the coupling, with and without

bending. During the test, the sealing capability of the coupling was evaluated by internally pressurizing the

entire test specimen with water up to 165 bar. The tests were performed at room temperature.

The leakage from the threads of the sliding side of the coupling was measured and recorded. No leakage (less

than 0.05 mL/min) was measured from the threads on the fixed side of the coupling. The main source of the

leakage was identified from the safety pins and circumferential transition of the coupling (more details in

section 5.1). In accordance with the customer, this leakage was not measured during the test. A resume of the

leakage location and related information is outlined in Figure 2.

Figure 2: Schematic representation of the leakage experienced on the coupling


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Following a short description of the different stages of the test procedure for Test 1 and Test 2 (the complete

test procedure is reported in the Appendix A).

1. Axial Tension: the coupling was tensioned to 500kN to completely open the coupling and zero the

LVDT measures.

2. Axial Compression: The coupling was then closed and compressed up to -2000kN load.

3. Axial Tension: The coupling was opened and tensioned with 1000kN load

4. Axial Compression: The same as point 2

5. Axial Tension: The same as point 3

6. Compression with 0.17° bending: The same as point 2 with the addition of bending load (applied

curvature of 2.5°/30 m or 0.17°/2m).

7. Tension with 0.17° bending: The same as point 3 with the addition of bending load (applied

curvature of 2.5°/30 m or 0.17°/2m).

8. Compression with 0.33° bending: The same as point 2 with the addition of bending load (applied

curvature of 5°/30 m or 0.33°/2m).

9. Tension with 0.33° bending: The same as point 3 with the addition of bending load (applied

curvature of 5°/30 m or 0.33°/2m).

10. Axial tension until test sample fails: Tension the sample until the final failure

Test 3 was performed with a limited test procedure due to significant leakage from the circumferential

transition of the coupling. See Table 3 for details

During the different stages of the test procedure, the sample was pressurized with internal pressure up to 165

bar for 15 minutes and the leakage from the moving part of the coupling was measured. Due to the high

leakage from sample (from pins and transition area), it was not possible to reach the pressure requirement in

all the defined test conditions. Following a list of the different pressurization conditions during the test:

1. Fully open, 0 kN, 0.0°

2. Half open, 0 kN, 0.0°

3. Fully closed, -1000 kN, 0.0°



6. Fully open, 1000 kN, 0.0°

7. Fully open, 0 kN, 0.0°


9. Fully closed, 0 kN, 0.0°



12. Fully open, 1000 kN, 0.0°

13. Fully open, 0 kN, 0.17°/2m

14. Half open, 0 kN, 0.17°/2m

15. Fully closed, 0 kN, 0.17°/2m

16. Fully closed, -1000 kN, 0.17°/2m

17. Fully closed, -2000 kN, 0.17°/2m

18. Fully open, 1000 kN, 0.17°/2m

19. Fully open, 0 kN, 0.33°/2m

20. Half open, 0 kN, 0.33°/2m

21. Fully closed, 0 kN, 0.33°/2m

22. Fully closed, -1000 kN, 0.33°/2m

23. Fully closed, -2000 kN, 0.33°/2m

24. Fully open, 1000 kN, 0.33°/2m


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Where:

Fully open: Coupling completely open - LVDT coupling measuring 0mm

Half open: LVDT coupling measuring ≈10mm

Fully closed: LVDT coupling measuring ≈20mm

3.2 Test rig

The tests were carried out in a specific test rig located at Sintef's laboratory in Trondheim. The test rig

consists of two side plates connected by three high load hydraulic cylinders (two on the top and one on the

bottom). Both side plates are allowed to rotate around their middle axes while only one is allowed to slide

horizontally (see Figure 1 and Figure 3). The test sample is connected to both plates by using custom-made

flange fixed in place by sixteen M20 bolts. The rig design allows the simultaneous application of axial and

bending load, up to a total force of ≈8000kN. Photos of the test setup is shown in Figure 3 and Figure 4.

In addition, for the specific test requirement, an air operated pump (Hydratron AZ-1-425) was used to apply

the providing the hydraulic internal pressure to the sample during the test.

Figure 3. Test rig with test specimen installed


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Figure 4. Coupling and instrumentation

3.3 Instrumentation

The sample and the test rig were equipped with several sensors and measuring devices according to the client

specifications:

Inclinometer x 2: High accuracy T935-3 (Sherborne Sensors) inclinometers with ±3 deg range (±5V

linear output) were used during the test for recording the applied bending/angle on the sample. Two

inclinometers were placed on the pipe neutral axis close to the welding location, on the side of the

extension pipes. These were placed at 1m distance from the coupling centre position (see Figure 5 for

more details) – total distance 2m.

The total applied angle was measured as:

Total_Angle=ABS(Angle_Right)+ABS(Angle_Left)

LVDT x 2: LVDTs were placed across the coupling to evaluate its opening/closing during the test. Two

LVDTs were positioned at 12- and 6 o'clock. Note that for the first test, 4 LVDTs were used.

Unfortunately the measures at the neutral plane were unusable due their unclamping because of

movements during the test. The average value of the LVDT measures was used for defining the

coupling position.

Strain Gauge x 12: Strain gauges (SG) were placed on the extension pipes and coupling to evaluate the

applied strain induced by the applied load. Three axial locations were selected, see Figure 5 and Figure

6. For each location, four SGs were glued to the sample with 90deg spacing (12-, 3-, 6- and 9 o'clock

circumferential positions). A total of 12 SGs were used for each test, all measuring the strain in the axial

direction. SG type FLA-5-11-1L from Tokyo Sokki Kenkyujo was used for all the tests.

Internal Pressure sensor: The internal pressure in the pipe was measured by an HBM P3 high accuracy

pressure sensor (range 1 to 500Bar) placed in the extension pipe.

Total applied load: the internal cylinder pressures (in all three cylinders) and the relative positions were

measured with the 6 HBM P3IC pressure sensors (range 1 to 1000Bar) and LVDTs available in the test

machine. The pressure values in the cylinders were used to evaluate the applied load during the test.

More details about the calculation is found in Appendix B.


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Acquisition system:

An ad hoc acquisition system was developed in the HBM Catman Easy software for the monitoring and

recording of the measurements. The different measurements were sampled with a frequency of 2 Hz. HBM

MGC Plus amplifiers were used, except for the two LVDTs, where the signal were amplified by using a

HBM Scout 55 amplifier.

All the sensors and acquisition channels were verified and calibrated before the test. The calibration

documents are reported in Appendix B.

In addition to the previous reported instrumentation, during the different pressurization phases of the test, the

leakage on the moving part of the coupling was also measured. A bucket was placed under the connection to

collect the leakage water during the holding time. This was then manually weighted and recorded.

Figure 5. Positions of the instrumentation on the test specimen

Figure 6: Detailed position for SGs location in position 2 (SG2)


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3.4 Assembly and torque

The girth weld assembly of the flange, extension pipe and casing was performed by Technip/Orkanger.

Details of the preheating, type of welding, type of welding wire, weld heat input for the welding passes and

the results of the NDT can be delivered on request. Details of the geometry of the test specimen and flange

are presented in Appendix C.

The coupling was torqued according to the procedure provided by ISOR, see ref. /2/. Following the main

steps used to torque the coupling:

The entire coupling with flanges, casing and extension pipes was installed in the test machine. Only

one side of the pipe was fixed to the side plate, while the other end was kept free to rotate inside the

flange.

A two-plate system with 1m extension bar was used to clamp the free end of the coupling. The

torque was applied by using the available crane with accurate measure of the pulling load. This was

evaluated at 90deg angle (see Figure 7).

The coupling was torqued until reaching the pulling force (reading by the crane weigh sensor) of

approximately 1250 kg with an extension arm of 1m (torque = 12500Nm) as required by the

provided specifications.

Figure 7. Schematic representation of the system used to torque the pipe


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4 TEST RESULTS

Two tests were carried out according to the complete test procedure reported in the Appendix A. The main

results for each test are reported in the following sections.

For both tests, the water leakage during the pressurization phases did not allow the completion of the

required pressurization. For some of the test conditions the max allowed pressure was lower than the

required; consequently, a lower holding time was used in these conditions (2 minutes instead of the required

15 minutes). In Figure 8 some example are shown of the leakage during Test 1 and Test 2.

Figure 8. Leakage from the coupling during the application of the internal pressure for Test 1 and

Test 2, from pins and circumferential transition.

Figure 9. Leakage from the coupling during the application of the internal pressure for Test 3, from

particularly the circumferential transition.


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4.1 Test 1

Figure 10. Measured leakage at the sliding side of the coupling as function of the applied pressure.

Note: the measures were taken in a period of: 15 min when the 165Bar pressure was reached or 2 min

for a lower pressure (indicated by *)

Figure 11. Internal pressure envelope


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Figure 12. Coupling opening and applied force

Figure 13. Measured angle applied to the sample

Figure 14. Average strain measure for each location (the SGs in location three suffered a problem

during the mid part of the test – the related values are not reported here)


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Figure 15. Zoom on the final part of the test with the complete failure

Figure 16. Failure area


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Table 1: Leakage measurements

Measuring

point

Position

[mm]

Force

[kN]

Angle

[°/2m]*

Pressure

[Bar]

Time

[min]

Leakage

[mL/min]

1 - Fully open 0 0 0 115 0 0

2 - Fully closed 20 0 0 144 0 2

3 - Fully closed 20 -1000 0 165 15 1.3

4 - Fully closed 20 -2000 0 165 15 0.3

5 - Half open 10 0 0 165 2 8

6 - Fully open 0 1000 0 96 2 0

7 - Fully open 0 0 0 143 2 0

8 - Half open 10 0 0 158 2 5

9 - Fully closed 20 0 0 155 2 4

10 - Fully closed 20 -1000 0 165 15 0.5

11 - Fully closed 20 -2000 0 165 15 0.4

12 - Fully open 0 1000 0 100 2 0

13 - Fully open 0 0 0.17 146 2 0

14 - Half open 10 0 0.17 155 2 3.5

15 - Fully closed 20 0 0.17 145 2 4

16 - Fully closed 20 -1000 0.17 145 2 2.5

17 - Fully closed 20 -2000 0.17 165 15 0.2

18 - Fully open 0 1000 0.17 80 2 0

19 - Fully open 0 0 0.33 146 2 0

20 - Half open 10 0 0.33 155 2 3.5

21 - Fully closed 20 0 0.33 145 2 4

22 - Fully closed 20 -1000 0.33 145 2 2.5

23 - Fully closed 20 -2000 0.33 165 15 0.2

24 - Fully open 0 1000 0.33 80 2 0

*: Angle per 2m, coupling in the centre.

Comment, Test 1

During the execution of test one, it was noticed that the coupling was sliding (within the sliding part

of the test) when reaching a force of approximately 200kN. The obtained sliding force did not

present any variation even when bending was applied to the coupling.

The final failure happened at a total tensile load of 1837kN. The failure was initiated by shear of the

pins.

The detailed results from the SG measurements are presented in Appendix E.


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4.2 Test 2






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Figure 20: Measured angle applied to the sample

Figure 21. Average strain measure for each location


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Figure 22. Zoom on the final part of the test with the complete failure

Figure 23. Failure area


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Measuring

point

Position

[mm]

Force

[kN]

Angle

[°/2m]*

Pressure

[Bar]

Time

[min]

Leakage

[mL/min]

1 - Fully open 0 0 0 120 1 0

2 - Fully closed 20 0 0 134 2 2

3 - Fully closed 20 -1000 0 165 15 0.3

4 - Fully closed 20 -2000 0 165 15 0.2

5 - Half open 10 0 0 135 1 1

6 - Fully open 0 1000 0 97 1 0

7 - Fully open 0 0 0 117 1 0

8 - Half open 10 0 0 130 1 1.5

9 - Fully closed 20 0 0 130 1 0.5

10 - Fully closed 20 -1000 0 165 15 0.5

11 - Fully closed 20 -2000 0 165 15 0.2

12 - Fully open 0 1000 0 97 1 0

13 - Fully open 0 0 0.17 110 1 0

14 - Half open 10 0 0.17 135 1 1.5

15 - Fully closed 20 0 0.17 127 1 2

16 - Fully closed 20 -1000 0.17 165 15 0.3

17 - Fully closed 20 -2000 0.17 165 15 0.3

18 - Fully open 0 1000 0.17 85 1 0

19 - Fully open 0 0 0.33 101 1 0

20 - Half open 10 0 0.33 120 1 1

21 - Fully closed 20 0 0.33 125 1 1

22 - Fully closed 20 -1000 0.33 145 1 0.5

23 - Fully closed 20 -2000 0.33 165 15 0.2

24 - Fully open 0 1000 0.33 65 1 0

*: Angle per 2m with the coupling in the centre.

Comments, Test 2

Due to the leakage on Test 1, it was decided, in agreement with ISOR, to apply silver soldering on

the main leakage source of Test 2 to try to reduce the water flow during the test. Castolin 1020 XFC

was used for this purpose. This was applied by Oxy-fuel welding after pre-heating the component to

200°C for 2h in an electric oven (see Figure 24). The sealing solution, unfortunately, was not

successfully (too small gap that did not allowed the soldering to penetrate). For this reason, also Test

2 suffered of the same leakage with the consequent impossibility to reach the required pressure for

some of the test conditions.

During the installation of Test 2 it was necessary to force the component in place by applying few

mm of lateral movement. This was probably induced by a small misalignment in the pipes related to

the girth welding.

During the execution of Test 2, it was noticed that the coupling was sliding (within the sliding part of

the test) when reaching a force of approximately 300kN. The obtained sliding force did not present

any variation even when bending was applied to the coupling.

The final failure happened at a total tensile load of 1926kN. The failure was initiated by shear of the

pins.



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Figure 24. Silver soldering on Test 2 to try to reduce the leakage


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4.3 Test 3






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Figure 28: Measured angle applied to the sample

+

Figure 29. Average strain measure for each location

-25

-15

-5

5

15

25

35

-3000

-2000

-1000

0

1000

2000

3000

4000

0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.0 400.0

Co

up

ling

op

enin

g [m

m]

Tota

l Lo

ad [

kN]

Time [Min]

Total Load Coupling Opening


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Figure 30. Zoom on the final part of the test with the complete failure. The curve starts to deviate from

the elastic line (black dotted) at about 2200kN, indicating initial local yielding in the coupling. The test

was performed at a continuous displacement rate of 2mm/min.

Figure 31. Failure by means of rupture (shear) when the moving part of the coupling was pulled out


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Measuring

point

Position

[mm]

Force

[kN]

Angle

[°/2m]*

Pressure

[Bar]

Time

[min]

Leakage

[mL/min]

1 - Fully open 0 0 0 155 2 0

2 - Fully closed 20 0 0 162 2 2.5

3 - Fully closed 20 -1000 0 165 15 3.30

4 - Fully closed 20 -2000 0 165 15 0.46

5 - Half open 10 0 0 165 15 1

6 - Fully open 0 1000 0 125 2 0

7 - Fully open 0 0 0

Test Not Performed

8 - Half open 10 0 0

9 - Fully closed 20 0 0

10 - Fully closed 20 -1000 0

11 - Fully closed 20 -2000 0

12 - Fully open 0 1000 0

13 - Fully open 0 0 0.17

14 - Half open 10 0 0.17

15 - Fully closed 20 0 0.17

16 - Fully closed 20 -1000 0.17

17 - Fully closed 20 -2000 0.17

18 - Fully open 0 1000 0.17

19 - Fully open 0 0 0.33 158 15 0

20 - Half open 10 0 0.33 165 15 12.5

21 - Fully closed 20 0 0.33 165 15 6

22 - Fully closed 20 -1000 0.33 165 15 1.7

23 - Fully closed 20 -2000 0.33 165 15 0.2

24 - Fully open 0 1000 0.33 108 2 0

*: Angle per 2m with the coupling in the centre.

Comments, Test 3

The test 3 was carried out by using a high flow hydraulic pump capable to supply approximately 10

l/min of water at the maximum pressure of 200 Bar (previous tests were carried out with a pump

with maximum flow capacity of 0.5 l/min at 200 Bar). In specific condition, even the use of a high

flow pump did not manage to fully compensate the leakage flow. The leakage measures were carried

out over a period of 2 min instead of the planned 15 min (see Table 3 for more details).

During the execution of Test 3, it was noticed that the coupling was sliding (within the sliding part of

the test) when reaching a force of approximately 320kN. The obtained sliding force did not present

any variation even when bending was applied to the coupling.

Local initial yielding of the coupling occurred at about 2200kN tension force.

The final rupture occurred at a tensile load of 3135kN. The failure was initiated by the pull out of the

moving part of the coupling.



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5 DISCUSSION

5.1 Limitations of leakage rate

Due to the high leakage rates found during the testing for both Test 1 and Test 2, it was not possible to

complete the requirements of the Test Procedure regarding pressure and holding time. The provided test

description required to hold the internal pressure of 165 bar for 15 minutes. Due to the flow limitations of the

available pressure system (maximum flow of ≈0.5 L/min), it was not possible to reach the required pressures

for some cases (leakage rate higher than the maximum flow of the pump). In these cases, a shorter holding

time of 2 minutes was used. Distinctly higher leakage rate was identified for Test 3, located to the

circumferential transition of the coupling. For this test a pump with a maximum flow of about 10 L/min was

used.

Figure 32. Leakage areas of the coupling in red

5.2 Leakage rate measurement

During the test, the leakage rate from the sliding side of the coupling was measured by placing a bucket

under the related side of the coupling. These measures, however, could have been affected by the main

leakage on the coupling (not measured). Water spills coming from the central side of the coupling (safety

pins and circumferential transition), could have reached the measuring bucket and, to a minor extent,

affected the measured value. A conveyor to canalize the water leakage and reduce the possibility of

disturbing the measured values was used for Test 3.


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5.3 Comparisons of the final rupture loading

Test 1 and Test 2 present very similar test results during the final loading to rupture. The rupture load of Test

3 is significantly higher after modifications performed at ISOR. In Figure 33 and Figure 34, the final part of

the test, with the complete failure of the coupling, is reported and compared.

In agreement with the client, the procedure for the final failure of Test 3 was carried out slightly different

than Test 1 and Test 2. For Test 1 and Test 2 the loading was increased stepwise (500kN load increase) and

kept at the reached value for a minimum time of 60 seconds. For Test 3 the loading was carried out

monotonically until failure.

Table 4: Failure loads

Sample Failure Load [kN]

Test 1 1837

Test 2 1926

Test 3 3135

Figure 33. Force envelopes for the final failure of Test 1 (S1), Test 2 (S2) and Test 3 (S3).

Figure 34. Strain envelopes for the final failure of Test 1 (S1), Test 2 (S2) and Test 3 – average strain

measurements at each location.


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6 CONCLUSIONS

A prototype for flexible coupling is tested regarding mechanical integrity and leakage. The flexible coupling

is made for a 9⅝" casing.

A Test Procedure, partly based on the standard ISO/PAS 12835:2013(E), was followed. Tension-,

compression- and bending loadings were applied, in combination with internal pressure. The ranges were

1000 kN tension, 2000 kN compression, 0.33° bending over 2m (coupling in the centre) and 165 bars

pressure (water filled). Finally the coupling was tensioned until rupture. The tests were performed at room

temperature.

Three parallel tests were performed, and the obtained results are consistent. The mechanical integrity is

considered acceptable by means of:

The 20mm of axial sliding of the coupling worked well throughout the Test Procedure for the tests.

o The force for sliding was about 200kN for Test 1 and about 300kN for Test 2 and Test 3.

The obtained sliding forces did not present any variation even when bending was applied to

the coupling.

No damage or plastic deformations was identified during the tests before the final rupture test.

The rupture type of Test 1 and Test 2 are shear fractures of the safety pins, occurring at tension

forces 1837kN and 1926kN respectively

The rupture force of Test 3 was 3135kN when the moving part of the coupling was pulled out. Initial

local yielding inside the coupling started at about 2200kN

A small leakage rate (<0.05 mL/min) was found from the threads on the fixed side of the coupling. Higher

leakage rates was found from the threads on the moving side of the coupling, ranging from 0 up to 12.5

mL/min. The maximum recommended limits of the referred test standard are 1 mL/min under compression

loads and 10 mL/min under tension- or bending loads. However, the requirements for high

temperature geothermal applications still remain to be defined.

Leakages from the safety pins and the circumferential transition of the coupling were significantly higher

than the standard requirement. For Test 3 the flow rate through the circumferential transition was several

litres per minute.

7 REFERENCES

/1/ Test standard ISO/PAS 12835:2013(E).

/2/ Geowell, Technical Report. Gunnar Skúlason Kaldal, Bjarni Steinar Gunnarsson "Guidelines for

Make-up Torque and Testing Procedure for Flexible Couplings", version 2.0, March 2017.

/3/ Geowell, Deliverable D4.1. Gunnar Skúlason Kaldal "Prototype design of Flexible Coupling",

version 1.0, November 2016.

/4/ ISOR Report. Bjarni Steinar Gunnarsson, Ingólfur Þorbjörnsson, Gunnar Skúlason Kaldal "Testing

of the Flexible Coupling", ISOR Report No ÍSOR-2016/059, September 2016.


REPORT NO. 2017:00254

VERSION 04

A - 1

Appendix A

SINTEFs practical interpretation of the Test Procedure


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VERSION 04

A - 2

Phase Action Details

1

Axia

l

ten

sio

n 1.1 In open position:

1.1.1 Pull with a machine displacement rate of 2mm/min

1.1.2 Stop when the load has reached +500±50 kN

2

Axia

l co

mp

res

sio

n

2.1 In open position: 2.1.1 Release tension with a machine

displacement rate of 2mm/min 2.1.2 Stop when the load has reached 0±50 kN;

compensate to keep the load constant (every minute)

2.1.3 Zero Coupling LVDT measure (reference zero position for the coupling)

2.1.4 Pressurize with water to 16.5±0.25 MPa and hold for 15 min

2.1.5 Depressurize in open water channel 2.2 While closing:

2.2.1 Compress at machine displacement rate of 2 mm/min

2.2.2 Stop when reach 20 mm displacement measured at the coupling LDVT


2.2.4 Depressurize in open water channel 2.3 In closed position:

2.3.1 Compress with a machine displacement rate of 2mm/min

2.3.2 Stop when the load has reached -1000±50 kN - compensate to keep the load constant (every minute)

2.3.3 Pressurize with water to 16.5±0.25 MPa and hold for 15 min 1

2.3.4 Depressurize in open water channel 2.3.5 Compress with a machine displacement rate of

2mm/min 2.3.6 Stop when the load has reached -2000±50 kN2 -

compensate to keep the load constant (every minute) – Check the average level of strain is approximately 0.11%

2.3.7 Pressurize with water to 16.5±0.25 MPa

and hold for 15 min. 3

2.3.8 Depressurize and open water channel

1 If no leakage is detected in 2.2.3 then 2.3.3 and 2.3.4 can be skipped and compression can be continued, according to 2.3.5, after 1 min. stop.

3 If no leakage is detected in 2.3.3 (or if it was skipped) then 2.3.7 and 2.3.8 can be skipped and compression can be released, according to


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A - 3

3.1.1, after 1 min. stop.

3

Axia

l te

nsio

n

3.1 In closed position: 3.1.1 Release compression with a machine

displacement rate of 2mm/min 3.1.2 Stop when the load has reached -1000±50 kN

and hold for 1 min 3.1.3 Release compression with a machine

displacement rate of 2mm/min 3.1.4 Stop when the load has reached 0±50 kN

and hold for 1 min

3.2 While opening: 3.2.1 Open at a machine displacement 1-2 mm/min 3.2.2 Stop after 10 mm displacement measured

at the LVDT coupling 3.2.3 Pressurize with water to 16.5±0.25 MPa

and hold for 15 min. 3.2.4 Depressurize in open water channel 3.2.5 Open at 2 mm/min machine displacement rate. 3.2.6 Stop at 0 mm measured at the LVDT

coupling (when coupling is open) and hold for 1 min

3.3 In open position: 3.3.1 Pull with a strain rate of machine displacement 2

mm/min. 3.3.2 Stop when the load has reached +1000±50 kN-





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A - 4

4

Axia

l c

om

pre

ssio

n

4.1 In open position:

4.1.1 Release tension with a machine displacement rate of 2mm/min

4.1.2 Stop when the load has reached 0±50 kN; compensate to keep the load constant (every minute)


4.1.4 Depressurize in open water channel

4.2 While closing:









4.3 In closed position: 4.3.1 Compress with a machine displacement rate of 2mm/min

4.3.2 Stop when the load has reached -1000±50 kN - compensate to keep the load constant (every minute) 4.3.3 Pressurize with water to 16.5±0.25 MPa and hold for 15 min 4


4.3.4 Compress with a machine displacement rate of 2mm/min 4.3.5 Stop when the load has reached -2000±50 kN- compensate to keep the load constant (every minute) 4.3.6 Pressurize with water to 16.5±0.25 MPa and hold for 15 min 5


4 If no leakage is detected in 4.2.7 then 4.3.3 and 4.3.4 can be skipped and compression can be continued, according to 4.3.5, after 1 min. stop. 5 If no leakage is detected in 4.3.3 (or if it was skipped) then 4.3.7 and 4.3.8 can be skipped and compression can be released, according to 5.1.1, after 1 min. stop.


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A - 5

5 A

xia

l te

nsio

n





and hold for 1 min

5.2 While opening: 5.2.1 Open with a machine displacement rate of

2mm/min 5.2.2 Stop at 10 mm displacement measured at the

coupling LDVT and hold for 1 min 5.2.3 Open with a machine displacement rate of

2mm/min 5.2.4 Stop at 0 mm with a machine displacement rate

of 2mm/min (when coupling is open) and hold for 1 min

5.3 In open position: 5.3.1 Pull with a machine displacement rate of

2mm/min 5.3.2 Stop when the load has reached +1000±50 kN-





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A - 6

6

Co

mp

res

sio

n w

ith

ben

din

g


displacement rate of 2mm/min 6.1.2 Stop when the load has reached 0±50 kN 6.1.3 Apply curvature of 2.5°/30 m (0.17°/2m)



6.2 While closing: 6.1.1 Compress with a machine displacement

rate of 2mm/min 6.2.2 Stop at 10 mm displacement measured at

the coupling LDVT 6.2.3 Pressurize with water to 16.5±0.25 MPa

and hold for 15 min 6.2.4 Depressurize and open water channel 6.2.5 Compress with a machine displacement rate of

2mm/min 6.2.6 Stop after 20 mm displacement measured

at the coupling LDVT 6.2.7 Pressurize with water to 16.5±0.25 MPa

and hold for 15 min 6.2.8 Depressurize and open water channel

6.3 In closed position: 6.1.2 Compress with a machine displacement

rate of 2mm/min 6.3.1 Stop when the load has reached -1000±50 kN-



6.3.3 Depressurize and open water channel 6.1.3 Compress with a machine displacement

rate of 2mm/min 6.3.4 Stop when the load has reached -2000±50

kN- compensate to keep the load constant (every minute)


6.3.6 Depressurize and open water channel 6 If no leakage is detected in 6.2.7 then 6.3.3 and 6.3.4 can be skipped and compression can be continued, according to 6.3.5, after 1 min. stop. 7 If no leakage is detected in 6.3.3 (or if it was skipped) then 6.3.7 and 6.3.8 can be skipped and compression can be released, according to 7.1.1, after 1 min. stop.


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A - 7

7

Ten

sio

n w

ith

be

nd

ing





and hold for 1 min












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VERSION 04

A - 8

8

Co

mp

res

sio

n w

ith

ben

din

g


displacement rate of 2mm/min 8.1.2 Stop when the load has reached 0±50 kN 8.1.3 Apply curvature of 5°/30 m (0.33°/2m) 8.1.4 Pressurize with water to 16.5±0.25 MPa

and hold for 15 min 8.1.5 Depressurize and open water channel

8.2 While closing: 8.2.1 Compress with a machine displacement rate of


coupling LDVT 8.2.3 Pressurize with water to 16.5±0.25 MPa and

hold for 15 min 8.2.4 Depressurize and open water channel 8.2.5 Compress with a machine displacement rate of

2mm/min 8.2.6 Stop after 20 mm displacement measured at the

coupling LDVT 8.2.7 Pressurize with water to 16.5±0.25 MPa and

hold for 15 min 8.2.8 Depressurize and open water channel

8.3 In closed position: 8.3.1 Compress with a machine displacement rate of

2mm/min 8.3.2 Stop when the load has reached -1000±50 kN-



8.3.4 Depressurize and open water channel 8.3.5 Compress with a machine displacement rate of

2mm/min 8.3.6 Stop when the load has reached -2000±50 kN-




8 If no leakage is detected in 8.2.7 then 8.3.3 and 8.3.4 can be skipped and compression can be continued, according to 8.3.5, after 1 min. stop. 9 If no leakage is detected in 8.3.3 (or if it was skipped) then 8.3.7 and 8.3.8 can be skipped and compression can be released, according to 9.1.1, after 1 min. stop.


REPORT NO. 2017:00254

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A - 9

9

Ten

sio

n w

ith

be

nd

ing





and hold for 1 min











10 Compression with bending




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A - 10

11

Axia

l te

nsio

n u

nti

l te

st

sam

ple

fails

11.1 In open position: 11.1.1 Release curvature/bending – to

zero (0°/30 m) 11.1.2 Release tension/compression (if present) with a

machine displacement rate of 2mm/min 11.1.3 Stop when the load has reached 0±50 kN 11.1.4 Pull with a machine displacement rate of

2mm/min until a strain of Δ𝜖 = 0.05% has been added (average measure on the SG in the same location at different clock position)

11.1.5 Hold for 1 min 11.1.6 Pull with a machine displacement rate of

2mm/min until a strain of Δ𝜖 = 0.05% has been added (average measure on the SG in the same location at different clock position)

11.1.7 Pressurize with water to 16.5±0.25 MPa and hold for 15 min – Strain level not adjusted

11.1.8 Depressurize and open water channel 11.1.9 Repeat 11.1.4 – 11.1.6 until the sample,

casing or other components fails


REPORT NO. 2017:00254

VERSION 04

B - 1

Appendix B

Details of the instrumentation and calibrations


REPORT NO. 2017:00254

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B - 2

Total applied load calculation

The test rig is not equipped for direct measurement of the applied tensile force; the load is calculated by

measuring the oil pressure in the three double acting cylinders of the test rig (two in the top and one in the

bottom of the test rig).

The pressure values are measure on both faces of each piston by using two separate HBM pressure sensors.

The calibration data for each of the pressure sensors is reported in the attached appendix.

The test rig presents in total three hydraulic cylinders:

Top side: two identical cylinders with piston radius of Rpt=180mm and rod radius of Rrt=90mm

More details in the appendix.

Bottom side: single cylinder with internal diameters of Rpb =280mm and Rrb =120mm. More

details in the appendix

Top Cylinders (for single cylinder)

Area of the piston side 𝐴1𝑡 = 𝜋 × 𝑅𝑝𝑡2 = 𝜋 × 1802 = 101787 𝑚𝑚2

Area of the rod side 𝐴2𝑡 = 𝐴2𝑡 − [𝜋 × 𝑅𝑟𝑡2] = 101787 − [𝜋 × 902] = 76340 𝑚𝑚2

Force (considering P1t and P2t the pressure value) 𝐹𝑡𝑜𝑝 = (𝐴1𝑡 × 𝑃1𝑡) − (𝐴2𝑡 × 𝑃2𝑡)

Bottom Cylinder

Area of the piston side 𝐴1𝑏 = 𝜋 × 𝑅𝑝𝑏2 = 𝜋 × 2802 = 246300 𝑚𝑚2

Area of the rod side 𝐴2𝑏 = 𝐴2𝑏 − [𝜋 × 𝑅𝑟𝑏2] = 246300 − [𝜋 × 1202] = 201061 𝑚𝑚2

Force (considering P1b and P2b the pressure value) 𝐹𝑏𝑜𝑡𝑡𝑜𝑚 = (𝐴1𝑏 × 𝑃1𝑏) − (𝐴2𝑏 × 𝑃2𝑏)

Total force

𝐹 = (2 × 𝐹𝑡𝑜𝑝) + 𝐹𝑏𝑜𝑡𝑡𝑜𝑚


REPORT NO. 2017:00254

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B - 3


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B - 4


REPORT NO. 2017:00254

VERSION 04

B - 5

Calibration certificate

Machine pressure sensors


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B - 6


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B - 7

Inclinomenters


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B - 8


REPORT NO. 2017:00254

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C - 1

Appendix C

Geometry, dimensions and fabrication of test specimens and fixtures


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C - 2


REPORT NO. 2017:00254

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C - 3

The material certificates of the casings and the extension pipes are available on request.

The material of the flanges is S355 construction steel. The material of the flange inserts is S420G2+Q+M

construction steel.

The grooving and weld assembly was performed by Technip-Orkanger. Preheating is included and the

interpass temperatures was registered.

The co-axiality of the assembled pipes/flange was the most important parameter. NDT, by means of manual

x-ray, MUT and MT, was performed. Details of the welding and NDT can be delivered on request.


REPORT NO. 2017:00254

VERSION 04

D - 1

Appendix D

Receipt of testing material


REPORT NO. 2017:00254

VERSION 04

D - 2

The final two couplings were received late April 2017. Two couplings were tested in August. The third was

returned to ISOR for modification, due to unexpected leakage from the pins and circumferential transition.


REPORT NO. 2017:00254

VERSION 04

D - 3

Return of the third coupling after modifications.


REPORT NO. 2017:00254

VERSION 04

E - 1

Appendix E

Detailed results of the Strain Gauges


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E - 2

Test 1:

SG position 1


REPORT NO. 2017:00254

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E - 3

Test 1:

SG position 2


REPORT NO. 2017:00254

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E - 4

Test 1:

SG position 3

Comments:

After about 100

minutes three of the

strain gauges starts

to drift. This is could

probably be caused

by water spill.

The day after (after

about 340 minutes),

the strain gauges are

back on track.


REPORT NO. 2017:00254

VERSION 04

E - 5

Test 2:

SG position 1

Comments:

The 3 o'clock strain

gauge seems to have

wrong amplification.

However, this has

been checked out,

and it is other

unknown error has

occurred.


REPORT NO. 2017:00254

VERSION 04

E - 6

Test 2:

SG position 2

Comments:

The 12 o'clock strain

gauge drifts after

300 minutes, most

probably caused by

water spill. The

same happens with

the 6 o'clock strain

gauge after 355

minutes.


REPORT NO. 2017:00254

VERSION 04

E - 7

Test 2:

SG position 3

Comments:

Unknown

error/deviation on

the 3 o'clock strain

gauge between 340

and 355 minutes.


REPORT NO. 2017:00254

VERSION 04

E - 8

Test 3:

SG position 1

Comments:

Spikes on SG1 6

o'clock due to water

leakage.


REPORT NO. 2017:00254

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E - 9

Test 3:

SG position 2


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E - 10

Test 3:

SG position 3

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