This topic will teach you how to determine water requirement (gal/sack) and yield of cement (gallon/sack) as per cement slurry program.
The cement formula given from town is listed below:
Cement formula:
Class G cement
35% Silica sand (35% by weight of cement)
0.2 gps of chemical A
0.6 gps of chemical B
Required cement density = 15.5 ppg
The absolute volume of each material is listed below:
Class G cement = 0.0382 gal/lb
Silica sand = 0.0456 gal/lb
Chemical A = 0.0974 gal/lb
Chemical B = 0.103 gal/lb
Determine requirement (gal/sack), yield of cement
We still use the same concept as previous calculation:
Volume = Weight x Absolute Volume
Where:
Volume in gal/sack
Weight in lb/sack
Absolute volume in gal/lb
We can create table showing each component of cement slurry as shown below:
| Weight (lb/sack) | Absolute volume (gal/lb) | Volume (Gal/sack) | |
| 1 sack of class G cement | 94 | 0.0382 | 94 x 0.0382 = 3.591 |
| 35% Silica sand | 0.35 x 94 = 32.9 | 0.0456 | 32.9 x 0.0456 = 1.5 |
| Chemical A | 0.2 ÷ 0.0974 = 2.053 | 0.0974 | 2.053 x 0.0974 = 0.2 |
| Chemical B | 0.6 ÷ 0.103 = 5.825 | 0.103 | 5.825 x 0.103 = 0.6 |
| Water | 8.33 x k | 1/8.33 | k |
| Total | 94+32.9+1.0267+5.825+(8.33k) | 3.591+1.5+0.2+0.6+k |
where; k is the variable that must be solved.
Total weight per sack of cement =94+32.9+1.0267+5.825+8.33k = 133.7517 + 8.33k
Total volume of cement slurry per sack of cement = 3.591+1.5+0.2+0.6+k = 5.891 + k
Cement Density = Total weight per sack of cement ÷ Total volume of cement slurry
15.5 = (133.7517 + 8.33k) ÷ (5.891 + k)
Solve for k: k = 5.92
After k is solved, you will get water requirement and cement yield.
The water requirement is 5.92 gal/sack.
Yield of cement = 5.891 + 5.92 = 11.811 gal/sack
Ps: I did not give you the product name in this topic or anything related to any cementing companies because I want you to understand the calculation concept. If you understand the concept, everything will be good.
Cementing Technology Books
Formulas and Calculations for Drilling, Production and Workover, Second Edition
how to calculated absolute volume?
You don’t need to calculate the absolute volume. Each material has its own absolute volume that you can find from any cement handbook.
You have a mistake.Absolute volume is in gal/lb, but in top of the table it is in gal/sack
Thanks for checking my typo. I correct it already.
You have written Absolute Volume (.0103) of chemical B in table, which is not so what you have listed above (.103). Why?
shubham,
It is 0.013. The typo error was corrected already. Thanks for informing us.
Regards,
Shyne