C7+ Fraction Concentration (For Gas Condensates)

The heptane-plus fractions composition of original reservoir gas can be estimated using the initial producing gas/condensate ratio. Also when the well-stream gas composition data are not available, the C7+ fraction can be estimated using well-stream gas specific gravity.

The relationship between the composition of heptanes plus in percent and initial producing gas/condensate ratio is a power function.

References: Tools To Manage Gas/Condensate Reservoirs; Novel Fluid-Property Correlations on the Basis of Commonly Available Field Data, Ovalle, A. P., Lenn, C. P., & McCain, W. D. (2007) Two-Phase Compressibility Factors for Retrograde Gases, D. G. Rayes; L. D. Piper; W. D. McCain, Jr.; S. W. Poston


  • 1-Rayes et al
  • 2-Ovalle et al

Input Parameters

NameInput Value - UnitConverted ValueValidityLink to Calculation Page
Well Stream Specific Gravity



Producing Gas/Condensate Ratio



This is the value at reservoir pressures above dew point.


CorrelationCalculated ValueWarningsRemarks
1-Rayes et al11.898%
2-Ovalle et al0.582%