Characteristic Time for Linear Diffusion in Reservoirs Formula
Characteristic Time for Linear Diffusion in Reservoirs calculates characteristic diffusion time for pvt and rock-fluid properties workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (Phi, beta_f, beta_r, mu, l, k) are known and the assumptions behind the cited pvt and rock-fluid properties 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, tau equals 7,645.670317 s.
0.2
3e-6
5e-6
1
100
100
Inputs
Phi
fractionPorosity
beta_f
1/psiFluid Compressibility
beta_r
1/psiRock Compressibility
mu
cPViscosity
l
ftCharacteristic Length Scale of Diffusion
k
mDPermeability
Outputs
tau
Characteristic Diffusion Time
Phi
Porosity (rearranged)
beta_f
Fluid Compressibility (rearranged)
beta_r
Rock Compressibility (rearranged)
mu
Viscosity (rearranged)
l
Length Scale (rearranged)
k
Permeability (rearranged)
Source and review
reviewedZoback, M. D. Reservoir Geomechanics, Cambridge University Press, UK, Page: 41.
Source