Methane from gas venting and leaks
Mass of methane and CO₂ in vented or leaked gas and the CO₂ equivalent, from the gas volume at standard conditions and its composition: blowdowns, process losses, emergency releases.
CH₄ = V · y_CH₄ · 16.043 / V_mCO₂ = V · y_CO₂ · 44.01 / V_mCO₂e = GWP · CH₄ + CO₂The methodology for greenhouse gas emissions from oil and gas production (Order No. 9, para 24) calculates methane from process losses as V · 16 / 22.4 · y_CH₄. 22.4 m³/kmol is the molar volume at 0 °C while the gas volume there is at 20 °C, so that formula gives 7.4 % more. By default the calculator uses 24.055 m³/kmol, the molar volume at the same 20 °C; the other option uses 22.4 as the methodology does (with methane's molar mass of 16.043 rather than the rounded 16). The gas is taken as ideal (about 0.2 % error for methane at standard conditions). Where leaks are measured, the measurements are used instead (paras 23–24 of the methodology).
Source: Order No. 9 of 17.01.2023, methodology for greenhouse gas emissions from oil and gas production, paras 23–25; Environmental Code, Art. 282
Inputs
You can change a field's unit: the value is converted to the formula's units automatically.
At standard conditions (20 °C, 101.325 kPa); enter a volume at 0 °C in Nm³ and it is converted.
From a gas analysis; associated and gas-lift gas usually hold 70–90 %.
IPCC AR5: 28, the default (national inventory under the Paris Agreement); AR4: 25; AR6 (fossil methane): 29.8.
Unit converter for this formulaGas volume · Mass · Fraction and percent
- Sm³ (20 °C)1
- 10³ Sm³0.001
- 10⁶ Sm³1·10⁻⁶
- 10⁹ Sm³1·10⁻⁹
- Sm³ (15 °C)0.982944
- Nm³ (0 °C)0.931776
- scf34.7793
- Mscf0.0347793
- MMscf3.47793·10⁻⁵
- Bcf3.47793·10⁻⁸
Gas at standard conditions, 101.325 kPa: Sm³ at 20 °C (GOST 2939, used in Kazakhstan), Sm³ (15 °C) per ISO 13443 and SPE, Nm³ at 0 °C, scf at 60 °F. Gas volumes convert by the ideal-gas law, so 1 Sm³ = 34.78 scf (not 35.31 as for a geometric volume).
- CO₂ — CO₂ mass in the gas–
- CO₂e — Total in CO₂ equivalent–
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Results are engineering estimates from standard formulas; for design decisions check them against the codes, project documents and specialists' calculations. The formulas carried over from the original set are unchanged, and their errors are described in the notes.