Dynamic Settling/Stability Workgroup – Summer
2013
Robert Beirute, Beirute Consulting; Heath Williams, Schlumberger; Paul Sonnier and Jeff
Watters, CSI, Deryck Williams, ChevronTexaco; Greg Garrison and Katrina Price, OTC; Graeme
Anthony, OFIte
June 25th, Houston, TX
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Agenda
1. Minutes of Previous Meeting and Action Items
2. Overview of Workgroup objectives/progress
3. Procedures to run dynamic vs. static testing for
Workgroup
4. Summary of API Cooperative test results
5. Our roadmap moving forward
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TG on Test Methods for Determination of Dynamic Settling
• Several task group members were present.
• Meeting Minutes for January 22nd, 1:15pm held at the Intercontinental New Orleans, LA
• Review of testing conducted so far which included a hematite system that failed both the dynamic
settling and free fluid testing, and the spacer system which passed both the dynamic and free fluid
test.
• A system that passed both free fluid and DST
• A system that will pass the free fluid but fail the DST is still being designed
• The chairman made the comment that static settling has the potential to develop gel strengths which
can aid in stability whereas dynamic settling does not allow for development of the gel strength.
Action Items
• After much discussion it was decided to pursue the development of Designs 1 and 2
• Continue the round robin testing for the next meeting in the summer.
• Designing system for round robin testing that passes static criteria and fails dynamic criteria
• Updating the procedure to include the syringe method for taking the density readings of top, middle
and bottom.
• Update the procedure to include the weighing of the paddle before and after the test.
Indicates Action Items that have been completed
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Minutes of Previous Meeting
Completion/Progress and Projected Timeline
Explored DST
alternatives
Phase 1 – showed
systems that
passed/failed Static and
DST
01-2012
06-2012
01-2013
06-2013
01-2014
06-2014
100%
80%
Phase 2 – cement failed
DST but passed static
Phase 2 – Updated
procedures and begin
technical report
Phase 3 - Submit
report/procedures for
comments and review
from DST Workgroup
Phase 4 - Submit
report/procedures for
comments and review
from SC10
Phase 5 - Final
report/procedures
ratified by SC10
60%
40%
20%
0%4
% Workgroup Completion
06-2011
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Timeline (2012-2015)
Objectives for Phase 2 Testing
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 Test a cement system that would show unique value of DST for
performance-based cement stability evaluation
o 1. Pass GO/NO testing with minimal increase in BC (less than 50BC)
o 2. Pass free fluid criteria with less than 1% free fluid.
o 3. Pass sedimentation test criteria with less than 5% settling
o 4. Fail DST criteria with more than 5% change in density trend measured
down the length of the slurry HPHT cup after DST testing
o 5.Fail DST cone height measurements (greater than 0.5 inch in height)
 Add test procedures and interpretation guidelines
o Define motor speed at 25 rpm
o Ramp to BHCT following well schedule, Stabilize for at least 30 min, Turn
motor speed to 25 rpm for 30 min, Shutoff motor ensure lab to lab
uniformity in low shear exposure period, cool to 190deg as soon as
possible and perform measurements
o Use DST cone height results for under-dispersion/over-dispersion at 5
Previous version(s)
Updated version
Motor speed was varied between 25-35 rpm,
depending on procedure
25 rpm is locked as the one motor speed
Motor speed was left at 25-35 rpm for at least 20
min period and cool-down period also
Motor speed is left at low shear for at least 30
minutes and then the motor is shut down before
cool-down period
No attempt was made to quantify under and
over-dispersion with DST
Attempt is made to quantify under and overdispersion with DST with simple mathematical
relationship
No density trend with syringes
10-mL tared syringes used to collect from upper,
middle, and lower thirds of slurry cup
Only center cone height used as consideration
Center, ½ radius or middle, and radius or outside
positions are used in mathematical relationship =
%deg dispersion = (center cone height-outside
cone height)/center cone height x 100%
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Phase 2 – Updated DST Procedure and
comparison with older versions of procedure
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Unpacking List
.\Unpacking List and Dynamic Weigh Out Sheet _CD_RHW_15 May 2013.pdf
DST Procedure
Dynamic Settling Test Procedure _ Ramp up to 350
degF.docx
GO/NO and Free Fluid Procedure
Free Fluid Test after Conditioning in HPHT
Consistometer_15 May 2013.docx
Sedimentation Test
API Sedimentation Test.docx
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Link to DST, GO/NO GO – Free Fluid, and
Sedimentation Updated Procedures
Workgroup Cooperative Testing Summary
WG1 WG2 WG3
BHCT (degF)
WG4
WG5
Ave
STDev
350
GO/NO GO Init/Max BC
NA
12/7
24/28
4/8
15/33
12/23
7/13
Free Fluid (%)
NA
0
0
5
1.3
1.6
2.4
FF Angle (deg)
NA
45
45
45
45
45
NA
Sedimentation. Test (max dev.) (%)
NA
3.0
1.7
NA
0.5
1.7
1.3
Yes
Yes
Yes
Yes
-
DST – dens top 1/3rd (lbm/gal)
15.4 15.9
15.2
14.5
13.7
14.9
0.9
DST - dens mid 1/3rd (lbm/gal)
16.7 17.2
16.2
17.6
16.8
16.9
0.5
DST – dens bott 1/3rd (lbm/gal)
NA
16.9
16.7
18.2
16.9
17.2
0.7
% difference density top-bottom
8.4
0
9.9
25.5
23.4
14.7
9.0
1
1.5
1.1
1.5
1.5
1.3
0.3
Cone height – 1/2R or middle (in.)
0.63
1.5
1.1
0.8
1.3
1.1
0.4
Cone height – R or outside(in.)
0.31
1.4
1.0
1.0
1.1
1.0
0.4
Degree of dispersion (%)*
69
6.7
9.1
33.3
26.7
29.0
25.1
DST Slurry Stability Criteria Achieved?**
No
No
No
No
No
No
Static Slurry Stability Achieved?
Cone height – center (in.)
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Workgroup Members
1STD
2STD
* Greater than 50% difference between center and outside cone height indicates underdispersed slurry
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** Less than 50% difference and cone height less than 0.5 in. for any measurement location is stable slurry as per DST criteria
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GO/NO GO Test Results
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GO/NO test observations after pulling paddle
CSI
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SLB
OTC
10
SLB
CVX
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Free fluid observations after conditioning in GO/NO GO
test and 2 hrs at ambient temp as per API RP10B-2
CSI
OFIte
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DST consistency behavior during motor speed at 25
rpm
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DST cone observations after revised DST
procedure and removing modified paddle
CSI
OTC
CVX
OFIte
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SLB
13
 Go/No Go test results – Average Min/Max BC 12/23 with StDev 7/13
 Free fluid test results at 45deg angle – Average 1.6% with StDev 2.4%
─ 2 workgroup members had 0% free fluid with 1 workgroup member showing 5.0%
 Static Sedimentation – Average 1.7% with STDev 1.3%
─ Depending on individual organization best practices, typically less than 5% is stable
 DST syringe density trend– Average 14.7% with STDev 9.0%
─ 2 workgroup members had less 10% and 2 had more than 23%
 DST cone height – Average 1.3,1.1,1.0 with STDev 0.3, 0.4, 0.4
 Degree of Dispersion – Average 29.0% with STDev 25.1%
─ 1 workgroup member had outlier of 69%
─ Either procedure needs to be clarified further to emphasize unpacked cone over
packed cone for height measurements
─ Perhaps angle of cone slope needs to be explored instead of % difference of height
─ Other methods needs to be explored
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Conclusions
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Our Roadmap…
• Collect more cooperative data from workgroup
members
• Look at alternative ways of describing dispersion
(slope of cone using Pythagorean theory?)
• Write technical report/RP for workgroup input and
comments
• Submit workgroup-validated report/RP to SC10 for
input and comments
• Submit technical report/RP to SC10 for
vote/ratification
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Questions from the Audience
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