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Formation Fluid Compressibility - Acidizing Formula

Kfl=SoKo+SwKw+SgKgK_{fl}=S_oK_o+S_wK_w+S_gK_g

Formation Fluid Compressibility - Acidizing calculates formation fluid compressibility for hydraulic fracturing workflows in production engineering.

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How engineers use this formula

Use this formula when the listed inputs (S_o, S_w, S_g, K_o, K_w, K_g) are known and the assumptions behind the cited hydraulic fracturing 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, K_fl equals 0.000017 psi^-1.

S_ofraction

0.7

S_wfraction

0.2

S_gfraction

0.1

K_opsi^-1

0.000012

K_wpsi^-1

0.000003

K_gpsi^-1

0.00008

Inputs

S_o

fraction

Oil Saturation Fraction

S_w

fraction

Water Saturation Fraction

S_g

fraction

Gas Saturation Fraction

K_o

psi^-1

Oil Isothermal Compressibility

K_w

psi^-1

Water Isothermal Compressibility

K_g

psi^-1

Gas Isothermal Compressibility

Outputs

K_fl

psi^-1

Formation Fluid Compressibility

K_o

psi^-1

Oil Isothermal Compressibility

K_w

psi^-1

Water Isothermal Compressibility

K_g

psi^-1

Gas Isothermal Compressibility

Source and review

reviewed

Williams, B.B., Gidley, J.L. and Schechter, R.S. 1979. Acidizing Fundamentals. Henry L. Doherty Memorial Fund of AIME, Society of Petroleum Engineers of AIME, Page 56.

Source

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