Characteristic Time for Linear Diffusion in Reservoirs Calculator
Enter the required inputs, confirm the units, and run the calculator to solve tau. Review the formula source and assumptions before using the result in engineering work.
Calculation context and source notes
Characteristic Time for Linear Diffusion in Reservoirs calculates characteristic diffusion time for pvt and rock-fluid properties workflows in reservoir engineering. The page keeps the declared variables, units, source relationship, and output definition visible for technical review.
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.
Solves for
tau (s)
Best next page
Formula, variables, and sourceFormula, variables, and default calculation
Reproducible default result
With the default values shown below, the calculation returns tau = 7,645.670317 s. Defaults demonstrate the implementation; they are not recommended field values.
0.2
3e-6
5e-6
1
100
100
Input definitions
Phi
fractionPorosity
beta_f
1/psiFluid Compressibility
beta_r
1/psiRock Compressibility
mu
cPViscosity
l
ftCharacteristic Length Scale of Diffusion
k
mDPermeability
Output definitions
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)
Engineering use, assumptions, and limits
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.
Frequently asked questions
What inputs does the Characteristic Time for Linear Diffusion in Reservoirs calculator need?
The calculation uses Porosity (Phi), Fluid Compressibility (beta_f), Rock Compressibility (beta_r), Viscosity (mu), Characteristic Length Scale of Diffusion (l), Permeability (k). Enter values on the units shown beside each field.
What result does this calculator return?
The primary result is characteristic diffusion time in s. The formula section shows the declared relationship, variables, and a reproducible default calculation.
What should I check before using the result?
Confirm the unit basis, source applicability, and input quality. The calculation does not replace a full engineering model or operating procedure. Mixing unit systems without converting the inputs.
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.
Zoback, M. D. Reservoir Geomechanics, Cambridge University Press, UK, Page: 41.
Open source reference