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Phase Behavior and ThermodynamicsFluid Properties

Stock-Tank Oil Density from API Gravity Calculator

ρo,st=ρw141.5API+131.5\rho_{o,st}=\rho_w\frac{141.5}{API+131.5}

Enter the required inputs, confirm the units, and run the calculator to solve rho_o_st. Review the formula source and assumptions before using the result in engineering work.

Tabular solver

Inputs

Defaults provide a quick field-unit example for the equation.

2 variables

Calculation runs locally with the shared TypeScript engine.

Formula reference

Stock-Tank Oil Density from API Gravity calculates stock-tank oil density for fluid properties workflows in phase behavior and thermodynamics.

View formula, units, and source

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.

Common mistakes

  • Mixing unit systems without converting the inputs.
  • Using default example values as field recommendations.
  • Applying the formula outside the source assumptions.