Phase Behavior and ThermodynamicsFluid Properties
Formation Water Specific Gravity from Density Formula
Formation Water Specific Gravity from Density calculates formation water specific gravity for fluid properties workflows in phase behavior and thermodynamics.
How engineers use this formula
Use this formula when the listed inputs (rho_w) are known and the assumptions behind the cited fluid 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, SG_w equals 1.047607 dimensionless.
rho_wlbm/ft3
65.4
Inputs
rho_w
lbm/ft3Formation Water Density
Outputs
SG_w
dimensionless
Formation Water Specific Gravity
rho_w
lbm/ft3
Formation Water Density
Source and review
reviewedWater salinity from density equation, McCain, W.D. Jr., Pengtools
McCain, W.D. Jr. 1990. Properties of Petroleum Fluids; Pengtools Water Salinity from Density example.
Source