Production EngineeringWell Performance
Average Liquid Specific Gravity for Mixed Liquid Stream Formula
Average Liquid Specific Gravity for Mixed Liquid Stream calculates average liquid specific gravity for well performance workflows in production engineering.
How engineers use this formula
Use this formula when the listed inputs (q_o, S_o, q_w, S_w) are known and the assumptions behind the cited well performance 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, S_L equals 1.047059 specific gravity.
q_obbl/day
200
S_ospecific gravity
0.8
q_wbbl/day
1500
S_wspecific gravity
1.08
Inputs
q_o
bbl/dayOil or Condensate Rate
S_o
specific gravityOil or Condensate Specific Gravity
q_w
bbl/dayWater Rate
S_w
specific gravityWater Specific Gravity
Outputs
S_L
specific gravity
Average Liquid Specific Gravity
S_o
specific gravity
Oil or Condensate Specific Gravity
S_w
specific gravity
Water Specific Gravity
q_o
bbl/day
Oil or Condensate Rate
q_w
bbl/day
Water Rate
Source and review
reviewedAPI RP 14E Appendix A flowline sizing example computes an average liquid specific gravity for hydrocarbon-water mixtures.
SourceRelated formulas and calculators
Effective Wellbore Radius of a Well in Presence of Uniform Flux Fractures
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Effective Wellbore Radius of a Horizontal Well – Method 1 (Anisotropic Reservoirs)
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Effective Wellbore Radius of a Horizontal Well – van der Vlis et al. Method
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