Calculations for the number of feet to be cemented

Input(s)

H: Hole Size (in.)

OD: Outer Diameter (in.)

ID: Inner Diameter (in.)

$\mathrm{N}_{\mathrm{s}}$: Number of Sacks of Cement to be Used (sacks)

$\mathrm{Y}_{\mathrm{s}}$: Slurry Yield $\left(\mathrm{ft}^{3} / \mathrm{stroke}\right)$

$\mathrm{h}_{\mathrm{c}}$: Feet of Casing $(\mathrm{ft})$

$\mathrm{h}_{\mathrm{sd}}$: Setting Depth of Cementing Tool or Feet of Drill Pipe (ft)

DC: Drill Pipe Capacity (bbl/stroke)

E: Original+extra Volume Req in Percentage (fraction)

PO: Pump Output (bbl/stroke)

Output(s)

AC: Annular Capacity $\left(\mathrm{ft}^{3} / \mathrm{ft}\right)$

$\mathrm{CC} * *$: Casing Capacity $\left(\mathrm{ft}^{3} / \mathrm{ft}\right)$

$\mathrm{C}_{\mathrm{c}}$: Casing Capacity $\left(\mathrm{ft}^{3}\right)$

$\mathrm{V}_{\mathrm{s}}$: Volume of Slurry $\left(\mathrm{ft}^{3}\right)$

$\mathrm{h}_{\mathrm{a}}$: Height of Cement in Annulus (ft)

$\mathrm{h}_{\mathrm{tc}}$: Depth of Top of Cement in Annulus $\left(\mathrm{ft}^{3} /\right.$ stroke $)$

$\mathrm{N}_{\mathrm{m}}$: Number of Barrels of Mud Required to Displace the Cement (bbl)

S: Number of Strokes Required to Displace the Cement (Strokes)

Formula(s)

$$ \begin{gathered} \mathrm{AC}=\frac{\mathrm{H}^{2}-\mathrm{OD}^{2}}{183.35} \\ \mathrm{CC}=\frac{(\mathrm{ID})^{2}}{183.35} \\ \mathrm{C}_{\mathrm{c}}=\mathrm{N}_{\mathrm{s}} * \mathrm{Y}_{\mathrm{s}} \\ \mathrm{V}_{\mathrm{s}}=\left(\mathrm{h}_{\mathrm{c}}-\mathrm{h}_{\mathrm{sd}}\right) * \mathrm{CC} \\ \mathrm{h}_{\mathrm{a}}=\frac{\left(\mathrm{V}_{\mathrm{s}}-\mathrm{C}_{\mathrm{c}}\right)}{\frac{\mathrm{AC}}{\mathrm{E}}} \\ \mathrm{h}_{\mathrm{tc}}=\mathrm{h}_{\mathrm{c}}-\mathrm{h}_{\mathrm{a}} \\ \mathrm{N}_{\mathrm{m}}=\mathrm{h}_{\mathrm{sd}} * \mathrm{DC} \\ \mathrm{S}=\frac{\mathrm{N}_{\mathrm{m}}}{\mathrm{PO}} \end{gathered} $$

Reference(s)

Lapeyrouse, N. J., 2002, Formulas and Calculations for Drilling, Production and Workover, Second Edition, Gulf Professional Publishing, Page: 57.