Appendix

Measurement units and conversion factors

7.9

AppendixMeasurement units and conversion factors

Reporting companies are encouraged to use generally accepted international units and to provide standard conversion factors.

These conversion factors should only be used when the data units differ from those required but the ad hoc conversion factor is not known (for example, when data related to the quantity of oil produced are expressed in barrels of oil equivalent (BOE) instead of metric tonnes but the mean density of the oil produced is unknown).

The assumptions underlying the conversion factors are:

• density of the oil 0.84 t m-3

• density of the condensate 0.75 t m-3

• density of the associated gas 1 kg m-3

• density of the non-associated gas 0.80 kg m-3

• density of chemicals, solvents, and all other products spilled 1.0 t m-3

Conversion factors for hydrocarbon production:

• 1 bbl of oil ≅ 0.159 m3 ≅ 0.134 t (metric tonne)

• 1 bbl of condensate ≅ 0.119 t

• 1000 m3 of associated gas ≅ 1.00 t

• 1000 m3 of non-associated gas ≅ 0.80 t

• 1000 ft3 of associated gas ≅ 28.3 m3 ≅ 0.0283 t

• 1000 ft3 of non-associated gas ≅ 28.3 m3 ≅ 0.0226 t

• 1000 bbl per day ≅ 48910 t per year

Conversion factors for atmospheric emissions:

• CH4: Density: 0.714x10-3 t m-3

• SO2: Mean density: 2.89x10-3 t m-3 1 t SO3 ≅ 1.20 t SO2

• NOx: Mean density 2.02x10-3 t m-3 1 t NO ≅ 0.94 t NO2

• CO2: Density: 1.96x10-3 t m-3

Conversion factors for produced water discharges:

• 1 bbl ≅ 0.159 m3

• 1 bbl per day ≅ 58.0 m3 per annum

Measurement units and conversion factors

7.10

SUSTAINABILITY REPORTING GUIDANCE FOR THE OIL AND GAS INDUSTRY

Conversion factors for oil spills:

• 1 bbl of oil ≅ 0.159 m3 ≅ 0.159 m3 or ≅ 0.134 t

• 1 bbl of condensate ≅ 0.119 t

• 1 bbl of chemicals & others ≅ 0.159 t

Conversion factors for energy consumption:

• 1 calorie = 4.1868 joule

• GCV = Gross calorific value (= Higher heating value, HHV)

• NCV = Net calorific value (= Lower heating value, LHV)

Diesel qualities (density and heating value) may differ from one part of the world to another. In lack of correct (local) data, the following values may be used:

• 1 t of diesel oil ≅ 42.8 GJ (GigaJoules)

• 1 m3 of diesel oil ≅ 36.0 GJ, assuming a density of 0.84 t/m3

Field specific data for net calorific values (NCV) should be used if available. If such data are unavailable, the following values can be used:

• 1 Sm3 of natural gas (gas fields) ≅ 38 MJ (MegaJoules)

• 1 Sm3 of associated gas (oil fields) ≅ 42 MJ

• 1 Sm3 of gas, unspecified ≅ 40 MJ

Ratios between GCV and NCV depend on hydrocarbon composition. Field specific data should therefore be used if available: If such data are unavailable, the following values can be used:

• Gas: GCV/NCV ≅ 1.1

• Oil: GCV/NCV ≅ 1.05

• Unspecified HC (oil and gas): GCV/NCV ≅ 1.075

The following default conversion factor can be used for purchased electricity, and assumes that the efficiency of electricity produced is 38% of the heat input:

• 1 kWh = 0.0096 GJ