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Skin Factor Due to Reduced Crushed-Zone Permeability Formula

sc=(kkdpkkd)12hpNLpln(rdprp)s_c=\left(\frac{k}{k_{dp}}-\frac{k}{k_d}\right)12\frac{h_p}{NL_p}\ln\left(\frac{r_{dp}}{r_p}\right)

Skin Factor Due to Reduced Crushed-Zone Permeability calculates skin factor due to reduced crushed-zone permeability for well performance workflows in production engineering.

Calculate

How engineers use this formula

Use this formula when the listed inputs (k, k_dp, k_d, h_p, N, L_p, r_dp, r_p) are known and the assumptions behind the cited well performance 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, s_c equals 24.953299 dimensionless.

kmD

100

k_dpmD

10

k_dmD

25

h_pft

30

Ncount

60

L_pft

1

r_dpft

0.5

r_pft

0.25

Inputs

k

mD

Formation Permeability

k_dp

mD

Crushed Zone Permeability

k_d

mD

Damage Zone Permeability

h_p

ft

Perforation Interval

N

count

Total Number of Perforations

L_p

ft

Depth of Penetration

r_dp

ft

Crushed Zone Radius

r_p

ft

Perforation Radius

Outputs

s_c

dimensionless

Skin Factor Due to Reduced Crushed-Zone Permeability

k_dp

mD

Crushed Zone Permeability

N

count

Total Number of Perforations

Source and review

reviewed

Joshi, S.D. 1991. Horizontal Well Technology, Page 504.

Source

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