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.

**Ref books: ****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