Geomechanics and FracturingNaturally Fractured Reservoirs

Matrix-Block Shape Factor from Dimensionless Constant Formula

\alpha=\frac{\sigma_D}{L_m^2}

Matrix-Block Shape Factor from Dimensionless Constant calculates matrix-block shape factor for naturally fractured reservoirs workflows in geomechanics and fracturing.

Calculate

How engineers use this formula

Use this formula when the listed inputs (sigma_D, 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 0.4958 1/ft^2.

sigma_Ddimensionless

49.58

L_mft

Inputs

sigma_D

dimensionless

Dimensionless Shape-Factor Constant

L_m

Characteristic Matrix Block Length

Outputs

alpha

1/ft^2

Matrix-Block Shape Factor

sigma_D

dimensionless

Dimensionless Shape-Factor Constant

L_m

Characteristic Matrix Block Length

Source and review

reviewed

Shape factor for regular and irregular matrix blocks in fractured porous media, Rostami, P., Sharifi, M., Dejam, M. (2020)

Rostami, P., Sharifi, M., and Dejam, M. 2020. Shape factor for regular and irregular matrix blocks in fractured porous media. Petroleum Science 17, 136-152.

Source