1. Alternative Mixing Procedure
RP 10B-2

2. Preparation of Slurries

3. The Problem Cement slurries foam
Non-foamer not effective in some cases
Latex / thixotropic / high density slurries
Results in testing - a lesser amount (mass) of cement slurry
Excess foaming affects
Thickening time tests
Sedimentation
Free water
Rheology
Compressive strength
Expansion

4. Alternative Mixing Procedure cont’d
Thickening Time Test
Lesser amount of slurry is placed in the slurry cup
2 thoughts to correct / compensate
Change diaphragm
Hub baffled
Flat rubber
Flat metal / flat rubber on top
Pull Vacuum on slurry
0.1 atm in SA Lab
Thickening time start Bc 4, 3:00 Bc 4
normal, rubber flat diaphragm
Thickening time start Bc 11, 3:00 Bc 9
1.5 mins vacuum, rubber flat diaphragm
Thickening time start Bc 7, 3:00 Bc 2
normal, metal flat diaphragm
Thickening time start Bc 10, 3:00 Bc 6
1.5 mins vacuum, metal flat diaphragm

5. Diaphragm Choices Hub baffled Flat rubber
Flat metal flat rubber on top

6. Baffled Diaphragm

7. Applying Vacuum

8. Effects of Foaming Volume after mixing Volume after vacuum released
Volume Theoretical
cc's
cc's difference from original %
diff
Volume slurry
615
0.0
vol after mixing
811
196
31.9
676 61
9.0
vol after Vacuum
661 46
7.5
623 8
1.3
vol after release vac
737
122
19.8
651 36
5.5

9. Observations on Cements that Foam (consistometer test cell)
vol with diaphragm
flat
477 cc's
baffled
472 cc's
Cement design 1 2
Density
PCF/PPG
atm bal.
113/15.1
111/14.8
press bal.
118.5/15.8
125/16.7 %
4.87
12.61
mL missing
21.90
56.76

10. Lab Equipment Exist – Modified Foam Jar
Connect fitting to jar cover to accommodate vacuum fittings

11. Way Forward?

12. Thickening Time Stirring RPMs
Why
Do we stir at 150 RPMs?
Old procedure for salt cement - Calvert?
Do we simulate batch mixing at same RPM’s as pumping cement through Coiled tubing????
Concerned with 50 sec initial mixing RPMs but 150 rpms is ok for long thickening times?
10 hours = 36,000 sec
Velocity changes from different well geometries ie. slurry inside casing then in annulus
Thickening time test performed at 200, 150, 100 and 50 rpms.
longer thickening times are recorded as RPMs are reduced.
50 RPMs – mins.
100 RPMs – 169 mins.
150 RPMs – 148 mins.
200 RPMs mins