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Well information:

Well is drilled with 8.5 inch bit to 9,015 MD/8,505 TVD with oil based mud(9.5 ppg). Estimated

hole sized based on an open hole log is 8.6 inch.

Previous casing size is 9-5/8 and its shoe is at 6,500 MD/5000TVD.

Plan to run 7 casing and planned shoe depth at 9,000MD/8,500TVD.

There is one float collar at 8960MD/8470 TVD.

Top of cement is 2000 ft above 9-5/8 casing.

Spacer volume is from top of cement to surface.

Casing information

7 casing ID = 6.185

9-5/8 casing ID = 8.85

Use hole size measured from the open hole log to determine cement volume.

The well schematic should look like this.

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Determine the following items:

Cement volume

Spacer volume

Displace volume

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As per the cement program, the final schematic will look like this.

Determine cement volume

Total cement volume = cement in the annulus between open hole and 7 casing + cement in

annulus between 9-5/8 casing and 7 casing + cement in shoe track

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There are three parts that you need to calculate in order to get total cement volume as listed

below:

1. cement in the annulus between open hole and 7 casing

2. cement in annulus between 9-5/8 casing and 7 casing

3. cement in shoe track

The cement volume is based on annular capacity multiplied by cement length of each section.

Cement in the annulus between open hole and 7 casing

Annular capacity between open hole and 7 casing = (8.62-7

2) 1029.4 = 0.02425 bbl/ft

Length from 7 casing shoe to 9-5/8 casing shoe = 9000 6500 = 2500 ft

Cement in the annulus between open hole and 7 casing = 0.024252500 = 60.6 bbl

Cement in annulus between 9-5/8 casing and 7 casing

Annular capacity between 9-5/8 casing and 7 casing = (8.852-72) 1029.4 = 0.02849 bbl/ft

Length of cement inside 7 casing = 2000 ft

Cement in annulus between 9-5/8 casing and 7 casing = 0.02849 x 2000 = 57 bbl

Cement in shoe track

Capacity of 7 casing = 6.1852

1029.4 = 0.03716 bbl/ft

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Shoe track length = 40 ft

Cement in shoe track = 40 x 0.03716 = 1.5 bbl

Total Cement Volume

Total cement = 60.6 + 57 + 1.5 = 119.1 bbl

Determine space volume

As per the cement program, spacer will be at surface.

Spacer volume = Annular capacity between 9-5/8 casing and 7 casing x length of spacer

Annular capacity between 9-5/8 casing and 7 casing = (8.852-7

2) 1029.4 = 0.02849 bbl/ft

Length of spacer = volume annulus to TOC

TOC 2000 ft inside casing shoe = 6,500 2,000 = 4,500 ft

Spacer volume = 0.02849 x 4,500 = 128.2 bbl

Determine displace volume

The displacement volume is from surface to the float collar where the top plug will sit on.

Displacement volume = Capacity of 7 casing x Length to the float collar

Capacity of 7 casing = 6.1852

1029.4 = 0.03716 bbl/ft

Length to the float collar = 8,960 ft

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Displacement volume = 0.03716 x 8960 = 333 bbl

Conclusion for this cement calculation

Cement volume = 119.1 bbl Spacer volume = 128.2 bbl

Displace volume = 333 bbl

With this example, I wish you would understand more about how to determine cement volume.

Please remember that any cement volume calculation is based on this concept.