Reservoir EngineeringWaterflooding and EOR
Steam-Oil Ratio - Marx and Langenheim Formula
Steam-Oil Ratio - Marx and Langenheim calculates steam-oil ratio for waterflooding and eor workflows in reservoir engineering.
How engineers use this formula
Use this formula when the listed inputs (W_s_eq, N_p) are known and the assumptions behind the cited waterflooding and eor 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, F_so equals 2 bbl steam/bbl oil.
W_s_eqbbl
100000
N_pbbl
50000
Inputs
W_s_eq
bblSteam used as water equivalent
N_p
bblCumulative oil produced
Outputs
F_so
bbl steam/bbl oil
Steam-oil ratio
W_s_eq
bbl
Steam used as water equivalent
N_p
bbl
Cumulative oil produced
Source and review
reviewedThermal Recovery, Prats, M. (1986)
Prats, M. 1986. Thermal Recovery. Society of Petroleum Engineers, New York, Chapter 7, Page 77.
Source