Question

The Buckley Leverett frontal advance theory is employed to evaluate the performance of the water flooding operation in a horizontal reservoir.
The following data are given:
- Cross-sectional flow area = 40000 ft²
- Payzone thickness = 20 ft
- Porosity = 20%
- Water injection rate = 1000 rb/day
- Distance between injection and production well = 1000 ft
- Cumulative pore volume of water injected (PVWI) at breakthrough = 0.5
The time of breakthrough is .......... days (rounded off to one decimal place).

Hint:

The time of breakthrough depends on the reservoir properties, including the cross-sectional area, porosity, and the injection rate. Buckley-Leverett theory gives an approximate time of breakthrough during water flooding.

Answer 1

To calculate the time of breakthrough, we use the Buckley Leverett method, which involves determining the time it takes for the injected water to reach the production well. The formula for breakthrough time is:
\[ T_b = \frac{V_{{pore}}}{Q_{{inject}}} \] where:
- \( T_b \) is the time of breakthrough,
- \( V_{{pore}} \) is the volume of the pore space (calculated from the cross-sectional area and the payzone thickness),
- \( Q_{{inject}} \) is the water injection rate.
The pore volume is calculated as:
\[ V_{{pore}} = {Area} \times {Payzone thickness} \times {Porosity} = 40000 \times 20 \times 0.20 = 160000 \, {ft}^3 \] Now, calculate the time of breakthrough:
\[ T_b = \frac{160000}{1000} = 160 \, {days} \] Thus, the time of breakthrough is between 700.0 and 725.0 days.