Welcome to Sigma Quadrant- Petroleum Engineering Books

# 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) ft3/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, ft3/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), ft3 /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, ft3/ft/ yield of cement
• Spacer volume ahead of slurry = volume of spacer behind slurry x annular capcity/ pipe volume, ft3
• Length of Plug = number of sacks x yield/ ( anular volume of pipe + annular volume)