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Reservoir EngineeringUnconventional Reservoirs

Apparent Sorption Compressibility Formula

cs=0.17525BgVLρBbLϕ(1+bLp)2c_s=\frac{0.17525B_gV_L\rho_Bb_L}{\phi(1+b_Lp)^2}

Apparent Sorption Compressibility calculates apparent sorption compressibility for unconventional reservoirs workflows in reservoir engineering.

Calculate

How engineers use this formula

Use this formula when the listed inputs (B_g, V_L, rho_B, b_L, phi, p) are known and the assumptions behind the cited unconventional reservoirs 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, c_s equals 0.000596 1/psi.

B_gbbl/SCF

0.005

V_LSCF/ton

600

rho_Bg/cm^3

1.5

b_L1/psi

0.02

phifraction

0.06

ppsi

1000

Inputs

B_g

bbl/SCF

Gas Formation Volume Factor

V_L

SCF/ton

Langmuir Volume Constant

rho_B

g/cm^3

Bulk Density of Coal Deposit

b_L

1/psi

Langmuir Pressure Coefficient

phi

fraction

Porosity

p

psi

Reservoir Pressure

Outputs

c_s

1/psi

Apparent Sorption Compressibility

B_g

bbl/SCF

Gas Formation Volume Factor

V_L

SCF/ton

Langmuir Volume Constant

rho_B

g/cm^3

Bulk Density of Coal Deposit

phi

fraction

Porosity

p

psi

Reservoir Pressure

Source and review

reviewed

Advanced Reservoir Engineering, Ahmed, T., McKinney, P.D. (2005)

Ahmed, T. and McKinney, P.D. 2005. Advanced Reservoir Engineering, Gulf Publishing of Elsevier, Chapter 3, Page 222.

source conflict
Source

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