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Reservoir EngineeringWaterflooding and EOR

Equivalent Atomic H/C Ratio for In-Situ Combustion Fuel Formula

xHC=4(1mCO)0.27cN2cO2cCO2+2mCO4x_{HC}=4(1-m_{CO})\frac{0.27c_{N2}-c_{O2}}{c_{CO2}}+2m_{CO}-4

Equivalent Atomic H/C Ratio for In-Situ Combustion Fuel calculates equivalent atomic hydrogen-to-carbon ratio of combustion fuel for waterflooding and eor workflows in reservoir engineering.

Calculate

How engineers use this formula

Use this formula when the listed inputs (m_CO, c_N2, c_O2, c_CO2) 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, x_HC equals 0.34 ratio.

m_COfraction

0.1

c_N2mole fraction

0.75

c_O2mole fraction

0.03

c_CO2mole fraction

0.15

Inputs

m_CO

fraction

Mole ratio of carbon monoxide to carbon emissions

c_N2

mole fraction

Nitrogen concentration

c_O2

mole fraction

Oxygen concentration

c_CO2

mole fraction

Carbon dioxide concentration

Outputs

x_HC

ratio

Equivalent atomic hydrogen-to-carbon ratio of combustion fuel

m_CO

fraction

Mole ratio of carbon monoxide to carbon emissions

c_N2

mole fraction

Nitrogen concentration

c_O2

mole fraction

Oxygen concentration

c_CO2

mole fraction

Carbon dioxide concentration

Source and review

reviewed

Thermal Recovery, Prats, M. (1986)

Prats, M. 1986. Thermal Recovery. Society of Petroleum Engineers, New York, Chapter 8, Page 91.

Source

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