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Reservoir EngineeringRock Properties

Core Bulk Volume from Saturated and Immersed Weights Formula

Vb=WsWiρsV_b=\frac{W_s-W_i}{\rho_s}

Core Bulk Volume from Saturated and Immersed Weights calculates bulk rock volume for rock properties workflows in reservoir engineering.

Calculate

How engineers use this formula

Use this formula when the listed inputs (W_s, W_i, rho_s) are known and the assumptions behind the cited rock 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.

Default example

Using the default inputs, V_b equals 100 cm^3.

W_sg

120

W_ig

20

rho_sg/cm^3

1

Inputs

W_s

g

Saturated Sample Weight in Air

W_i

g

Saturated Sample Weight Immersed in Liquid

rho_s

g/cm^3

Saturating Liquid Density

Outputs

V_b

cm^3

Bulk Rock Volume

W_s

g

Saturated Sample Weight in Air

W_i

g

Saturated Sample Weight Immersed in Liquid

rho_s

g/cm^3

Saturating Liquid Density

Source and review

reviewed

AAPG Wiki. Porosity, bulk volume measurement.

Source

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