** ****CEMENTING CALCULATIONS**

**Slurry Volume**

The slurry volume = cement volume, gal+ water volume, gal+ additive volume, gal

**Yield of Cement**

Y = yield of slurry = (slurry volume gal /7.48) ft^{3}/sack

**Cement Slurry Requirements**

Number of sacks of cement = slurry volume, cu.ft / yield of cement, cu.ft/sack

**Mix Water Requirement**

Mix water requirement = mix water per sack x number of sacks

Number of sacks of additive = number of sacks x percentage of additive

Weight of additive = number of sacks of additive x 94 lbs

**Slurry Density**

Slurry density = (weight of cement, lb+ weight of water, lb+ weight of additive, lb)/ (volume of cement, gal+ volume of water, gal+ volume of additive, gal)

**Hydrostatic Pressure Reduction**

Hydrostatic pressure reduction due to spacer = 0.292 (density of mud, ppg – density of spacer, ppg)x annular capacity, ft^{3}/ft x spacer volume, bbl

**Contact Time**

An estimation of the volume of cement needed for removal of mud cake by turbulent flow is :

Volume of fluid (in turbulent flow), ft^{3} /bbl= 5.616 x contact times, minutes x displacement rate, bbl/min

**Gas Migration Potential**

Gas migration potential = 1.67 x (length of the pipe column exposed to the cement from the reservoir zone, ft /( diameter of the hole, in – outside diameter of the casing pipe, in)/Formation pressure, psi

Ranges:

0 – 3 Low

3 – 8 Moderate

> 8 High

**Cement Plug**

Number of sacks of cement = length of plug, ft x capacity of the hole, ft^{3}/ft/ yield of cement

Spacer volume ahead of slurry = volume of spacer behind slurry x annular capcity/ pipe volume, ft^{3}

Length of Plug = number of sacks x yield/ ( anular volume of pipe + annular volume)

** **

**Other References**

More details can be obtained from __501 Solved Problems for Drilling __Operations.