1. Lesson 32 Cementing - Salt Solutions
PETE 411 Well Drilling
Lesson 32 Cementing - Salt Solutions

2. Cementing - Salt Solutions
Use of salt in Cement Slurries
Unsaturated Salt Solutions
Saturated Salt Solutions
Types Cements
Cement Additives
Examples

3. Read: Applied Drilling Engineering, Ch
Read: Applied Drilling Engineering, Ch. 3 HW #17 Cementing of Liner due November 27, 2002

4. Salt in Cement Slurries
Salt Zones
Salt-saturated cements were originally used for cementing casing strings through salt zones.
Fresh or unsaturated salt cement slurries will not bond satisfactorily to salt formations because the slurry tends to dissolve or leach away the salt at the wall of the hole.
Salt-saturated cements will not dissolve any more salt so a good bond can be achieved

5. Salt in Cement Slurries
Shale Zones
Many shales are sensitive to fresh water.
Salt helps to protect these shales in that they tend to prevent excessive sloughing or heaving of the shales.

6. Salt in Cement Slurries
Accelerator
In low concentrations salt tends to accelerate the setting of cement.
Retarder
In high concentrations ( >5% by wt. of water) the salt will tend to retard the setting of the cement.

7. Salt in Cement Slurries

8. Salt in Cement Slurries
Expansion
Salt results in a more expansive cement.
Freezing
Salt reduces the freezing temperature of cement slurries.

9. ppm or mg/L mg/L ppm EXAMPLE: 200,000 mg of NaCl 800,000 mg of H2O
1,000,000 mg of solution
< 1 litre of solution
of solution

10. Volume of Sodium Chloride Solution
EXAMPLE:
Adding 30 lbs of NaCl
to 100 lbs of H2O
increases the volume of solution by ~10.7%
30% by weight = 13.8% by volume
(SG = 2.17)

11. Density of Sodium Chloride Solution

18. Example: Salt Solutions
30% NaCl (by weight of water) is added to one gallon of fresh water.
Calculate the density of the mixture:
(i) Before the salt goes into solution
(ii) Using the solubility charts shown above.

19. Problem : Salt Solutions
(i) Assuming that

20. Problem : Salt Solutions
(ii) From the chart,
{ lb/gal vs lb/gal !! }
{ what if we had 60% salt? }

25. Problem
Calculate the density and yield of a cement slurry consisting of:
65% Class “A” cement
35% Pozmix cement,
6% bentonite BWOC and
10.9 gal/sk of water.

26. Problem (i) Initial tabulations and calculations:
Weight Specific Density
Component lbs/sk Gravity lbs/gal
Class “A” *3.14 = 26.16
Pozmix *2.46 = 20.49
Bentonite *2.65 = 22.07
Water *1.00 = 8.33

27. Problem
(ii) Determine the properties of one sack of dry cement mixture; 65% Class “A” and 35% Pozmix:

28. (iii) Determine density and yield of final slurry:
Problem
(iii) Determine density and yield of final slurry:

29. Problem