Geomechanics and FracturingNaturally Fractured Reservoirs
Warren-Root Shape Factor from Fracture Sets Formula
Warren-Root Shape Factor from Fracture Sets calculates warren-root shape factor for naturally fractured reservoirs workflows in geomechanics and fracturing.
How engineers use this formula
Use this formula when the listed inputs (n, L_m) are known and the assumptions behind the cited naturally fractured reservoirs relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, alpha equals 0.6 1/ft^2.
ndimensionless
3
L_mft
10
Inputs
n
dimensionlessNumber of Normal Fracture Sets
L_m
ftMatrix Block Characteristic Length
Outputs
alpha
1/ft^2
Warren-Root Shape Factor
L_m
ft
Matrix Block Characteristic Length
n
dimensionless
Number of Normal Fracture Sets
Source and review
reviewedWarren, J.E. and Root, P.J. 1963. The Behavior of Naturally Fractured Reservoirs; summarized in Water 2024, 16(8), 1072.
SourceRelated formulas and calculators
Spherical Matrix Block Interporosity Flow Coefficient
Naturally Fractured Reservoirs