Shale Compaction Calculator
Enter the required inputs, confirm the units, and run the calculator to solve phi_e. Review the formula source and assumptions before using the result in engineering work.
Calculation context and source notes
Shale Compaction calculates compacted shale porosity for in-situ stress and rock mechanics workflows in geomechanics and fracturing. 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_s, sigma_v) are known and the assumptions behind the cited in-situ stress and rock mechanics relationship match the engineering case being checked.
Solves for
phi_e (fraction)
Best next page
Formula, variables, and sourceFormula, variables, and default calculation
Reproducible default result
With the default values shown below, the calculation returns phi_e = 0.234612 fraction. Defaults demonstrate the implementation; they are not recommended field values.
0.35
0.02
20
Input definitions
phi
fractionPorosity
beta_s
1/MPaEmpirical Compaction Constant
sigma_v
MPaVertical Effective Stress
Output definitions
phi_e
Compacted Shale Porosity
phi
Porosity
beta_s
Empirical Compaction Constant
sigma_v
Vertical Effective Stress
Engineering use, assumptions, and limits
Use this formula when the listed inputs (phi, beta_s, sigma_v) are known and the assumptions behind the cited in-situ stress and rock mechanics 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 Shale Compaction calculator need?
The calculation uses Porosity (phi), Empirical Compaction Constant (beta_s), Vertical Effective Stress (sigma_v). Enter values on the units shown beside each field.
What result does this calculator return?
The primary result is compacted shale porosity in fraction. 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.
Reservoir Geomechanics, Zoback, M.D. (2007)
Zoback, M.D. 2007. Reservoir Geomechanics. Cambridge University Press, Page 46.
Open source reference