calculation of production liner cementation

The calculation of production liner cementation involves determining the volume of cement required to properly cement the liner in place, ensuring zonal isolation and well integrity. Below is a step-by-step breakdown of the key calculations:

—

1. Determine Required Cement Volume
The total cement volume (\(V_{total}\)) is calculated based on:
– Annular capacity between the liner and open hole/casing
– Liner capacity (if cement is to be placed inside the liner)
– Excess factor (to account for irregularities in the hole)

# Formula:
\[
V_{total} = V_{annular} + V_{liner} + V_{excess}
\]

# a) Annular Volume (\(V_{annular}\))
\[
V_{annular} = \pi \times (D_h^2 – D_l^2) \times L / 4
\]
Where:
– \(D_h\) = Hole diameter (or previous casing ID if cemented inside)
– \(D_l\) = Liner outer diameter (OD)
– \(L\) = Length of liner to be cemented

# b) Liner Capacity (\(V_{liner}\))
If cement is also pumped inside the liner:
\[
V_{liner} = \pi \times D_i^2 \times h / 4
\]
Where:
– \(D_i\) = Liner inner diameter (ID)
– \(h\) = Height of cement inside the liner

# c) Excess Factor
Typically 10–50% extra volume is added to account for washouts or irregularities:
\[
V_{excess} = V_{annular} \times Excess\% / 100
\]

—

2. Calculate Slurry Yield & Cement Quantity
The amount of dry cement needed depends on the slurry yield (\(Y\)) per sack.

# Slurry Yield Formula:
\[
Y \, (\text{ft}^3/\text{sack}) = \frac{\text{Total slurry volume}}{\text{Number of sacks}}
\]

# Cement Quantity:
\[
\text{Sacks of cement} = \frac{V_{total}}{Y}
\]

—

3. Displacement Volume Calculation
The displacement volume is the amount of fluid (usually drilling mud) required to push the cement into place.

\[
V_{displacement} = \pi \times D_i^2 \times d / 4
\]
Where:
– \(D_i\)