Carter Leakoff Volume Calculator
Enter effective leakoff area, Carter leakoff coefficient, exposure time, and spurt-loss thickness in consistent units. The output is leaked fluid volume in cubic feet.
Calculation context and source notes
The Carter leakoff equation estimates hydraulic-fracturing fluid volume lost to the formation from leakoff area, Carter leakoff coefficient, exposure time, and instantaneous spurt-loss thickness.
Use the equation for a simplified fracture-fluid material-balance estimate when Carter square-root-of-time leakoff is an appropriate approximation. Keep the area basis consistent with the source model, especially for one face, two faces, one wing, or both wings.
Solves for
V_L (ft^3)
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Formula, variables, and default calculation
Reproducible default result
With the default values shown below, the calculation returns V_L = 1,329.516003 ft^3. Defaults demonstrate the implementation; they are not recommended field values.
20000
0.003
60
0.02
Input definitions
A_L
ft^2Leakoff Area
C_L
ft/min^0.5Carter Leakoff Coefficient
t
minElapsed Exposure Time
S_p
ftInstantaneous Spurt Loss
Output definitions
V_L
Leakoff Volume
A_L
Leakoff Area
C_L
Carter Leakoff Coefficient
t
Elapsed Exposure Time
S_p
Instantaneous Spurt Loss
Engineering use, assumptions, and limits
Use the equation for a simplified fracture-fluid material-balance estimate when Carter square-root-of-time leakoff is an appropriate approximation. Keep the area basis consistent with the source model, especially for one face, two faces, one wing, or both wings.
Assumptions
- Leakoff after spurt loss follows the Carter square-root-of-time approximation.
- The effective leakoff area and exposure time represent the fracture surface being modeled.
- Coefficient, time, area, and spurt-loss units are mutually consistent.
Limitations
- Does not solve coupled fracture propagation, changing pressure, filter-cake evolution, pressure-dependent leakoff, or reservoir heterogeneity.
- A single exposure time can be inadequate when fracture area grows continuously during pumping.
Common mistakes
- Double-counting or omitting a fracture face or wing in the leakoff area.
- Mixing minutes and seconds in the square-root time term.
- Using total injected fluid volume as leakoff area or treating leakoff volume as fracture volume.
Source and record status
Source metadata identifies the relationship implemented by the calculator. Check the cited edition, unit basis, and scope against the engineering case before operational use.
Espinoza, D.N. Introduction to Energy Geomechanics, Section 7.3.2.3, Carter leak-off equation.
Open source reference