Choice of method

The three methodological tiers for estimating fugitive emissions from oil and natural gas systems are described below.

tier 1

Tier 1 comprises the application of appropriate default emission factors to a representative activity parameter (usually throughput) for each applicable segment or subcategory of a country's oil and natural gas industry and should only be used for non-key sources. The application of a Tier1 approach is done using Equations 4.2.1 and 4.2.2 presented below:

Equation 4.2.1

Tier 1: estimating fugitive emissions from an industry segment E = a • EF

gas, industry segment industry segment gas, industry segment

Egasjndustry segement = Annual emissions (Gg)

Where:

Egasjndustry segement = Annual emissions (Gg)

EFgasindusiry segement = emission factor (Gg/unit of activity),

A industry segement = activity value (units of activity),

The industry segments to be considered are listed in Table 4.2.2. Not all segments will necessarily apply to all countries. For example, a country that only imports natural gas and does not produce any will probably only have gas transmission and distribution. The available Tier 1 default emission factors are presented in Tables 4.2.4 and 4.2.5 in Section 4.2.2.3. These factors have been related to throughput, because production, imports and exports are the only national oil and gas statistics that are consistently available. On a small scale, fugitive emissions are completely independent of throughput. The best relation for estimating emissions from fugitive equipment leaks is based on the number and type of equipment components and the type of service, which is a Tier-3 approach. On a larger scale, there is a reasonable relationship between the amount of production and the amount of infrastructure that exists. Consequently, the reliability of the presented Tier 1 factors for oil and gas systems will depend on the size of a country's oil and gas industry. The larger the industry, the more important its fugitive emissions contribution will be and the more reliable the presented Tier 1 emission factors will be.

Besides having a high degree of uncertainty, the Tier 1 approach for oil and natural gas systems does not allow countries to show any real changes in emission intensities over time (e.g., due to the implementation of control measures or changing source characteristics). Rather, emissions become fixed in proportion to the activity levels, and the changes in reported emissions over time simply reflect the changes in activity levels. Tier 2 and 3 approaches are needed to capture real changes in emission intensities. However, going to these higher tier approaches requires considerably more effort and, for Tier 3 approaches, more detailed activity data. The completeness and accuracy of the input information used for higher tier approaches will generally need to be comparable to, or better than, the values of the input information used for the lower methodological tiers in order to achieve more accurate results.

Fugitive greenhouse gas emissions from oil and gas related CO2 capture and injection activities (e.g., acid gas injection and EOR projects involving CO2 floods) will normally be small compared to the amount of CO2 being injected (e.g., less than 1 percent of the injection volumes). At the Tier 1 or 2 methodology levels they are indistinguishable from fugitive greenhouse gas emissions by the associated oil and gas activities. The emission contributions from CO2 capture and injection were included in the original data upon which the presented Tier 1 factors were developed (i.e., through the inclusion of acid gas injection and EOR activities, along with conventional oil and gas activities, with consideration of CO2 concentrations in the leaked, vented and flared natural gases, vapours and acid gases). Losses from CO2 capture should be accounted for in the industry where capture occurs, while losses from, transport, injection and storage activities are assessed separately in Chapter 5.

Table 4.2.2

Major categories and subcategories in the oil and gas industry

Industry Segment

Sub-Categories

Well Drilling

All

Well Testing

All

Well Servicing

All

Gas Production

Dry Gasa

Coal Bed Methane (Primary and Enhanced Production)

Other enhanced gas recovery

Sweet Gasb

Sour Gasc

Gas Processing

Sweet Gas Plants

Sour Gas Plants

Deep-cut Extraction Plantsd

Gas Transmission & Storage

Pipeline Systems

Storage Facilities

Gas Distribution

Rural Distribution

Urban Distribution

Liquefied Gases Transport

Condensate

Liquefied Petroleum Gas (LPG)

Liquefied Natural Gas (LNG) (including associated liquefaction and gasification facilities)

Oil Production

Light and Medium Density Crude Oil (Primary, Secondary and Tertiary Production)

Heavy Oil (Primary and Enhanced Production)

Crude Bitumen (Primary and Enhanced Production)

Synthetic Crude Oil (From Oil Sands)

Synthetic Crude Oil (From Oil Shales)

Oil Upgrading

Crude Bitumen

Heavy Oil

Waste Oil Reclaiming

All

Oil Transport

Marine

Pipelines

Tanker Trucks and Rail Cars

Oil Refining

Heavy Oil

Conventional and Synthetic Crude Oil

Refined Product Distribution

Gasoline

Diesel

Aviation Fuel

Jet Kerosene

Gas Oil (Intermediate Refined Products)

a Dry gas is natural gas that does not require any hydrocarbon dew-point control to meet sales gas specifications. However, it may still require treating to meet sales specifications for water and acid gas (i.e. H2S and CO2) content. Dry gas is usually produced from shallow (less than 1000 m deep) gas wells. b Sweet gas is natural gas that does not contain any appreciable amount of H2S (i.e. does not require any treatment to meet sales gas requirements for H2S). c Sour gas is natural gas that must be treated to satisfy sales gas restrictions on H2S content.

d Deep-cut extraction plants are gas processing plants located on gas transmission systems which are used to recover residual ethane and heavier hydrocarbons present in the natural gas.

TIER 2

Tier 2 consists of using Tier 1 equations (4.2.1 and 4.2.2) with country-specific, instead of default, emission factors. It should be applied to key categories where the use of a Tier 3 approach is not practicable. The country-specific values may be developed from studies and measurement programmes, or be derived by initially applying a Tier 3 approach and then back-calculating Tier 2 emission factors using Equations 4.2.1 and 4.2.2. For example, some countries have been applying Tier 3 approaches for particular years and have then used these results to develop Tier 2 factors for use in subsequent years until the next Tier 3 assessment is performed. In general, all emission factors (including Tier 1 and Tier 2 values) should be periodically re-affirmed or updated. The frequency at which such updates are performed should be commensurate with the rates at which new technologies, practices, standards and other relevant factors (e.g., changes in the types of oil and gas activities, aging of the fields and facilities, etc.) are penetrating the industry. Since new emission factors developed in this manner account for real changes within the industry, they should not be applied backwards through the time series.

An alternative Tier 2 approach that may be applied to estimate the amount of venting and flaring emissions from the production segment of oil systems consists of performing a mass balance using country-specific production volumes, gas-to-oil ratios (GORs), gas compositions and information regarding the level of gas conservation. This approach may be applied using equations 4.2.3 to 4.2.8 below and is appropriate where reliable venting and flaring values are unavailable but representative GOR data can be obtained and venting and flaring emissions are expected to be the dominant sources of fugitive emissions (i.e., most of the associated gas production is not being captured/conserved or utilized). Under these circumstances, the alternative Tier 2 approach may also be used to estimate fugitive greenhouse gas emissions from EOR activities provided representative associated gas and vapour analyses are available and contributions due to fugitive emissions from the CO2 transport and injection systems are small in comparison (as would normally be expected). Where the alternative Tier 2 approach is applied, any reported venting or flaring data that may be available for the target sources should not also be accounted for as this would result in double counting. However, it is good practice to compare the estimated gas vented and flared volumes determined using the GOR data to the available reported vented and flared data to identify and resolve any potential anomalies (i.e., the calculated volumes should be comparable to the available reported data, or greater if these latter data are believed to be incomplete).

Table 4.2.3 shows examples of typical GOR values for oil wells from selected locations. Actual GOR values may vary from 0 to very high values depending on the local geology, state of the producing reservoir and the rate of production. Notwithstanding this, average GOR values for large numbers of oil wells tend to be more predictable. A review of limited data for a number of countries and regions indicates that average GOR values for conventional oil production would usually be in the range of about 100 to 350 m3/m3, depending on the location.

Table 4.2.3

Typical ranges of gas-to-oil ratios for different types of production

Type of Crude Oil Production

Location

Typical GOR Values (m3/m3)

Range6

Average

Conventional Oil

Alaska (Prudhoe Bay)

142 to 62342 3

NA

Canada

0 to 2,000+

Not Available (NA)

Qatar (Onshore, 1 Oil Field)

167 to 1844

173

Qatar (Offshore, 3 Oil Fields)

316 to 3864

333

Primary Heavy Oil

Canada

0 to 325+ u

NA

Thermal Heavy Oil

Canada

0 to 901

NA

Crude Bitumen

Canada

0 to 201

NA

1 Source: Based on unpublished data for a selection of wells in Canada.

2 Appreciably higher GOR values may occur, but these wells are normally either classified as gas wells or there is a significant gas cap present and the gas would normally be reinjected until all the recoverable oil had been produced.

3 Source: Mohaghegh, S.D., L.A. Hutchins and C.D. Sisk. 2002. Prudhoe Bay Oil Production Optimization: Using Virtual intelligence Techniques, Stage One: Neural Model Building. Presented at the SPE Annual Technical Conference and Exhibition held in San Antonio, Texas, 29 September-2 October 2002.

4 Source: Corporate HSE, Qatar Petroleum, Qatar-Doha 2004.

5 Values as high as 7,160 m3/m3 have been observed for some wells where there is a significant gas cap present. Gas reinjection is not done in these applications. The gas is conserved, vented or flared.

6 Referenced at standard conditions of 15°C and 101.325 kPa.

To apply a mass balance method in the alternative Tier 2 approach, it is necessary to consider the fate of all of the produced gas and vapour. This is done, in part, through the application of a conservation efficiency (CE) factor which expresses the amount of the produced gas and vapour that is captured and used for fuel, produced into gas gathering systems or re-injected. A CE value of 1.0 means all gas is conserved, utilized or re-injected and a value of 0 means all of the gas is either vented or flared. Values may be expected to range from about 0.1 to 0.95. The lower limit applies where only process fuel is drawn from the produced gas and the rest is vented or flared. A value of 0.95 reflects circumstances where there is, generally, good access to gas gathering systems and local regulations emphasize vent and flare gas reduction.

Equation 4.2.3 Alternative tier 2 approach (emissions due to venting)

Egas,oil prod, venting = GOR • QoIL • - CE) • - XFlared ) • M gas • ygas • 42.3 X 10 6

Equation 4.2.4

Alternative tier 2 approach (ch4 emissions due to flaring)

Ech4,oil prod,flaring = GOR • QoIl • (1 - CE) • XPUred • (1 - FE) • MCH4 • yCH4 • 42.3 X10-6

Equation 4.2.5

Alternative tier 2 approach (co2 emissions due to flaring)

ECO2, oilprod, flaring = GOR • QOIL • (1 - CE) • Xplared • Mco2

•[[CO2 + (NcCH4 • yCH4 + NcNMVOC • ^NMVOC )(1 - XSoot)] 4-23x10-6

Equation 4.2.6 Ch4 emissions from flaring and venting

CH 4,oil prod CH 4, oil prod, venting CH 4,oil prod, flaring

Equation 4.2.7 Co2 emissions from venting and flaring

CO 2,oil prod CO 2,oil prod ,venting CO 2,oil prod , flaring

Equation 4.2.8 N2o emissions from flaring

EN2O,oil prod , flaring = GOR • Qoil (1 — CE )X Flared EFN2O

Where:

i, oil prod, venting i, oil prod, flaring

Qoil

Mgas

XFlared

42.3x10"'

= Direct amount (Gg/y) of GHG gas i emitted due to venting at oil production facilities. = Direct amount (Gg/y) of GHG gas i emitted due to flaring at oil production facilities. = Average gas-to-oil ratio (m3/m3) referenced at 15°C and 101.325 kPa. = Total annual oil production (103 m3/y).

= Molecular weight of the gas of interest (e.g., 16.043 for CH4 and 44.011 for CO2).

= Number of moles of carbon per mole of compound i (i.e., 1 for CH4, 2 for C2H6, 3 for C3H8, 1 for CO2, 2.1 to 2.7 for the NMVOC fraction in natural gas and 4.6 for the NMVOC fraction of crude oil vapours)

= Mol or volume fraction of the associated gas that is composed of substance i (i.e., CH4, CO2 or NMVOC).

= Gas conservation efficiency factor.

= Fraction of the waste gas that is flared rather than vented. With the exception of primary heavy oil wells, usually most of the waste gas is flared.

= flaring destruction efficiency (i.e., fraction of the gas that leaves the flare partially or fully burned). Typically, a value of 0.995 is assumed for flares at refineries and a value 0.98 is assumed for those used at production and processing facilities.

= fraction of the non-CO2 carbon in the input waste gas stream that is converted to soot or particulate matter during flaring. In the absence of any applicable data this value may be assumed to be 0 as a conservative approximation.

= emission factor for N2O from flaring (Gg/10 m3 of associated gas flared). Refer to the IPCC emission factor database (EFDB), manufacturer's data or other appropriate sources for the value of this factor.

= is the number of kmol per m3 of gas referenced at 101.325 kPa and 15°C (i.e. 42.3x10-3 kmol/m3) times a unit conversion factor of 10-3 Gg/Mg which brings the results of each applicable equation to units of Gg/y.

The values of Ech4, on prod, venting and Eco2, oil prod, venting in Equations 4.2.6 and 4.2.7 are estimated using Equation 4.2.3.

It should be noted that Equation 4.2.5 accounts for emissions of CO2 using a similar approach to what is done for fuel combustion in Section 1.3 of the Introduction chapter of the Energy Volume. The term yCO2 in this equation effectively accounts for the amount of raw (or formation CO2) present in the waste gas being flared. The terms NcCH4 • yCH4 and NcNMVOC • yNMVOC in Equation 4.2.5 account for the amount of CO2 produced per unit of CH4 and NMVOC oxidized.

TIER 3

Tier 3 comprises the application of a rigorous bottom-up assessment by primary type of source (e.g., venting, flaring, fugitive equipment leaks, evaporation losses and accidental releases) at the individual facility level with appropriate accounting of contributions from temporary and minor field or well-site installations. It should be used for key categories where the necessary activity and infrastructure data are readily available or are reasonable to obtain. Tier 3 should also be used to estimate emissions from surface facilities where EOR, EGR and ECBM are being used in association with CCS. Approaches that estimate emissions at a less disaggregated level than this (e.g., relate emissions to the number of facilities or the amount of throughput) are deemed to be equivalent to a Tier 1 approach if the applied factors are taken from the general literature, or a Tier 2 approach if they are country-specific values.

The key types of data that would be utilized in a Tier 3 assessment would include the following:

Facility inventory, including an assessment of the type and amount of equipment or process units at each facility, and major emission controls (e.g., vapour recovery, waste gas incineration, etc.).

Inventory of wells and minor field installations (e.g., field dehydrators, line heaters, well site metering, etc.).

Country-specific flare, vent and process gas analyses for each subcategory.

Facility-level acid gas production, analyses and disposition data.

Reported atmospheric releases due to well blow-outs and pipeline ruptures.

Country-specific emission factors for fugitive equipment leaks, unaccounted/unreported venting and flaring, flashing losses at production facilities, evaporation losses, etc.

The amount and composition of acid gas that is injected into secure underground formations for disposal.

Oil and gas projects that involve CO2 injection as a means of enhancing production (e.g., EOR, EGR and ECBM projects) or as a disposal option (e.g., acid gas injection at sour gas processing plants) should distinguish between the CO2 capture, transport, injection and sequestering part of the project, and the oil and gas production portion of the project. The net amount of CO2 sequestered and the fugitive emissions from the CO2 systems should be determined based on the criteria specified in Chapter 5 for CO2 capture and storage. Any fugitive emissions from the oil and gas systems in these projects should be assessed based on the guidance provided here in Chapter 4 and will exhibit increasing concentrations of CO2 over time in the emitted natural gas and hydrocarbon vapours. Accordingly, the applied emission factors may need to be periodically updated to account for this fact. Also, care should be taken to ensure that proper total accounting of all CO2 between the two portions of the project occurs.

4.2.2.3 Choice of emission factor tier 1

The available Tier 1 default emission factors are presented in Tables 4.2.4 and 4.2.5. All of the presented emission factors are expressed in units of mass emissions per unit volume of oil or gas throughput. While some types of fugitive emissions correlate poorly with, or are unrelated to, throughput on an individual source basis (e.g., fugitive equipment leaks), the correlations with throughput become more reasonable when large populations of sources are considered. Furthermore, throughput statistics are the most consistently available activity data for use in Tier 1 calculations.

Table 4.2.4 should only be applied to systems designed, operated and maintained to North American and Western European standards. Table 4.2.5 generally applies to systems in developing countries and countries with economies in transition where there are much greater amounts of fugitive emissions per unit of activity (often by an order of magnitude or more). The reasons for the greater emissions in these cases may include less stringent design standards, use of lower quality components, restricted access to natural gas markets, and, in some cases, artificially low energy pricing resulting in reduced energy conservation. Reference should also be made to the IPCC emission factor database (EFDB) since it would contain the values for higher tier emission factors.

Table 4.2.4

Tier 1 emission factors for fugitive emissions (including venting and flaring) from oil and gas operations in developed countriesa'b

Category

Subcategory0

Code

ch4

co2'

NMVOC

n2o

Units of measure

Value

Uncertainty (% of value)

Value

Uncertainty (% of Value)

Value

Uncertainty (% of value)

Value

Uncertainty (% of value)

Well Drilling

All

Flaring and Venting

l.B.2.a.ii or l.B.2.b.ii

3.3E-05

±100%

1.0E-04

±50%

8.7E-07

±100%

ND

ND

Gg per 103 m3 total oil production

Well Testing

All

Flaring and Venting

l.B.2.a.ii or l.B.2.b.ii

5.1E-05

±50%

9.0E-03

±50° o

1.2E-05

±50%

6.8E-08

-10 to ±1000%

Gg per 103 m3 total oil production

Well Servicing

All

Flaring and Venting

l.B.2.a.ii or l.B.2.b.ii

1.1E-04

±50%

1.9E-06

±50%

1.7E-05

±50%

ND

ND

Gg per 103 m3 total oil production

Production

All

Fugitives'1

to 2.3E-03

to 8.2E-05

to 5.5E-04

±100%

NA

NA

Gg per 106 m3 gas production

Flaring5

l.B.2.b.ii

7.6E-07

±25%

1.2E-03

±25%

6.2E-07

±25%

2.1E-08

-10 to ±1000%

Gg per 106 m3 gas production

Processing

Sweet Gas Plants

Fugitives

l.B.2.b.iii.3

4.8E-04 to 10.3E-04

±100%

1.5E-04to 3.2E-04

±100%

2.2E-04to 4.7E-04

±100%

NA

NA

Gg per 106 m3 raw gas feed

Flaring

l.B.2.b.ii

1.2E-06

±25%

1.8E-03

±25%

9.6E-07

±25%

2.5E-08

-10 to ±1000%

Gg per 106 m3 raw gas feed

Sour Gas Plants

Fugitives

l.B.2.b.iii.3

9.7E-05

±100%

7.9E-06

±100%

6.8E-05

±100%

NA

NA

Gg per 106 m3 raw gas feed

Flaring

l.B.2.b.ii

2.4E-06

±25%

3.6E-03

±25%

1.9E-06

±25%

5.4E-08

-10 to ±1000%

Gg per 106 m3 raw gas feed

Raw C02 Venting

l.B.2.b.i

NA

NA

6.3E-02

-10 to ±1000%

NA

NA

NA

NA

Gg per 106 m3 raw gas feed

Table 4.2.4(continued)

Tier 1 emission factors for fugitive emissions (including venting and flaring) from oil and gas operations

in developed countriesa'b

CH4

co2'

NMVOC

n2o

Category

Subcategory0

Code

Value

Uncertainty (% of value)

Value

Uncertainty (% of Value)

Value

Uncertainty (% of value)

Value

Uncertainty (% of value)

Units of measure

Deep-cut Extraction

Fugitives

l.B.2.b.iii.3

1.1E-05

±100%

1.6E-06

±100%

2.7E-05

±100%

NA

NA

Gg per 106 m3 raw gas feed

(Straddle

Plants)

Flaring

l.B.2.b.ii

7.2E-08

±25%

1.1E-04

±50%

5.9E-08

±25%

1.2E-08

-10 to ±1000%

Gg per 106 m3 raw gas feed

Weighted

Total

Fugitives

l.B.2.b.iii.3

1.5E-04 to 10.3E-04

±100%

1.2E-05 to 3.2E-04

±100%

1.4E-04 to 4.7E-04

±100%

NA

NA

Gg per 106 m3 gas production

Flaring

l.B.2.b.ii

2.0E-06

±25%

3.0E-03

±50%

1.6E-06

±25%

3.3E-08

-10 to ±1000%

Gg per 106 m3 gas production

Raw C02 Venting

l.B.2.b.i

NA

N/A

4.0E-02

-10 to ±1000%

NA

N/A

NA

N/A

Gg per 106 m3 gas production

Transmission & Storage

Transmission

Fugitives4

l.B.2.b.iii.4

6.6E-05 to 4.8E-04

±100%

8.8E-07

±100%

7.0E-06

±100%

NA

NA

Gg per 106 m3 of marketable gas

Venting

l.B.2.b.i

4.4E-05 to 3.2E-04

±75%

3.1E-06

±75%

4.6E-06

±75%

NA

NA

Gg per 106 m3 of marketable gas

Storage

Allk

l.B.2.b.iii.4

2.5E-05

-20 to ±500%

1.1E-07

-20 to ±500%

3.6E-07

-20 to ±500%

ND

ND

Gg per 106 m3 of marketable gas

Table 4.2.4(continued)

Tier 1 emission factors for fugitive emissions (including venting and flaring) from oil and gas operations in developed countriesa'b

Category

Subcategory0

Code

ch4

co2'

NMVOC

n2o

Units of measure

Value

Uncertainty (% of value)

Value

Uncertainty (% of Value)

Value

Uncertainty (% of value)

Value

Uncertainty (% of value)

Distribution

All

Allk

l.B.2.b.iii.5

1.1E-03

-20 to +500%

5.1E-05

-20 to ±500%

1.6E-05

-20 to ±500%

ND

ND

Gg per 106 m3 of utility sales

Natural Gas

Liquids

Transport

Condensate

Allk

l.B.2.a.iii.3

1.1E-04

±100%

7.2E-06

±100%

1.1E-03

±100%

nd

nd

Gg per 103 m3 Condensate and Pentanes Plus

Liquefied Petroleum

Gas

All

l.B.2.a.iii.3

na

na

4.3E-04

±50%

nd

nd

2.2E-09

-10 to ±1000%

Gg per 103 m3 LPG

Liquefied Natural Gas

All

l.B.2.a.iii.3

nd

nd

nd

nd

nd

nd

nd

nd

Gg per 106 m3 of marketable gas

Production

Conventional Oil

Fugitives (Onshore)

l.B.2.a.iii.2

1.5E-06 to 3.6E-03

±100%

1.1E-O7to 2.6E-04

±100%

1.8E-06 to 4.5E-03

±100%

na

na

Gg per 103 m3 conventional oil production

Fugitives (Offshore)

l.B.2.a.iii.2

5.9E-07

±100%

4.3E-08

±100%

7.4E-07

±100%

na

na

Gg per 103 m3 conventional oil production

Venting

l.B.2.a.i

7.2E-04

±50%

9.5E-05

±50%

4.3E-04

±50%

na

na

Gg per 103 m3 conventional oil production

Flaring

l.B.2.a.ii

2.5E-05

±50%

4.1E-02

±50%

2.1E-05

±50%

6.4E-07

-10 to ±1000%

Gg per 103 m3 conventional oil production

Table 4.2.4(continued)

Tier 1 emission factors for fugitive emissions (including venting and flaring) from oil and gas operations in developed countriesa'b

Category

Subcategory0

Code

ch4

co2'

NMVOC

n2o

Units of measure

Value

Uncertainty (% of value)

Value

Uncertainty (% of Value)

Value

Uncertainty (% of value)

Value

Uncertainty (% of value)

Oil/Cold

Bitumen

Fugitives

l.B.2.a.iii.2

7.9E-03

±100%

5.4E-04

±100%

2.9E-03

±100%

na

na

Gg per 103 m3 heavy oil production

Venting

l.B.2.a.i

1.7E-02

±75%

5.3E-03

±75%

2.7E-03

±75%

na

na

Gg per 103 m3 heavy oil production

Flaring

l.B.2.a.ii

1.4E-04

±75%

2.2E-02

±75%

1.1E-05

±75

4.6E-07

-10 to ±1000%

Gg per 103 m3 heavy oil production

Thermal Oil Production

Fugitives

l.B.2.a.iii.2

1.8E-04

±100%

2.9E-05

±100%

2.3E-04

±100%

na

na

Gg per 103 m3 thermal bitumen production

Venting

l.B.2.a.i

3.5E-03

±50%

2.2E-04

±50%

8.7E-04

±50%

na

na

Gg per 103 m3 thermal bitumen production

Flaring

l.B.2.a.ii

1.6E-05

±75%

2.7E-02

±75%

1.3E-05

±75%

2.4E-07

-10 to ±1000%

Gg per 103 m3 thermal bitumen production

Synthetic Crude (from Oilsands)

All

l.B.2.a.iii.2

2.3E-03

±75%

nd

nd

9.0E-04

±75%

nd

nd

Gg per 103 m3 synthetic crude production from oilsands

Table 4.2.4(continued)

Tier 1 emission factors for fugitive emissions (including venting and flaring) from oil and gas operations in developed countriesa'b

Category

Subcategory0

Code

CH,

co2'

NMVOC

n2o

Units of measure

Value

Uncertainty (% of value)

Value

Uncertainty (% of Value)

Value

Uncertainty (% of value)

Value

Uncertainty (% of value)

Synthetic Crude (from Oil Shale)

All

l.B.2.a.iii.2

ND

ND

ND

ND

ND

ND

ND

ND

Gg per 103 m3 synthetic crude production from oil shale

Default

Weighted

Total

Fugitives

l.B.2.a.iii.2

2.2E-03

±100%

2.8E-04

±100%

3.1E-03

±100%

na

NA

Gg per 103 m3 total oil production

Venting

l.B.2.a.i

8.7E-03

±75%

1.8E-03

±75%

1.6E-03

±75%

na

NA

Gg per 103 m3 total oil production

Flaring

l.B.2.a.ii

2.1E-05

±75%

3.4E-02

±75%

1.7E-05

±75

5.4E-07

-10 to ±1000%

Gg per 103 m3 total oil production

Oil Upgrading

All

All

l.B.2.a.iii.2

ND

ND

ND

ND

ND

ND

ND

ND

Gg per 103 m3 oil upgraded

Oil Transport

Pipelines

Allk

l.B.2.a.iii.3

5.4E-06

±100%

4.9E-07

±100%

5.4E-05

ND

NA

NA

Gg per 103 m3 oil transported by pipeline

Table 4.2.4(continued)

Tier 1 emission factors for fugitive emissions (including venting and flaring) from oil and gas operations in developed countriesa'b

Category

Subcategory0

Code

CH,

co2'

NMVOC

n2o

Units of measure

Value

Uncertainty (% of value)

Value

Uncertainty (% of Value)

Value

Uncertainty (% of value)

Value

Uncertainty (% of value)

Tanker Trucks and Rail Cars

Ventingk

l.B.2.a.i

2.5E-05

±50%

2.3E-06

±50%

2.5E-04

ND

NA

NA

Gg per 103 m3 oil transported by Tanker Truck

Loading of Off-shore Production on Tanker Ships

Ventingk

l.B.2.a.i

NDh

ND

NDh

ND

NDh

ND

NA

NA

Gg per 103 m3 oil transported by Tanker Ships

Oil Refining

All

All

l.B.2.a.iii.4

2.6xl0"6 to 41.0xl0"6

±100%

ND

ND

0.0013'

±100%

ND

ND

Gg per 103 m3 oil refined.

Refined Product Distribution

Gasoline

All

l.B.2.a.iii.5

NA

NA

NA

NA

0.0022j

±100%

NA

NA

Gg per 103 m3 product distributed.

Diesel

All

l.B.2.a.iii.5

NA

NA

NA

NA

ND

ND

NA

product transported.

Aviation Fuel

All

l.B.2.a.iii.5

NA

NA

NA

NA

ND

ND

NA

product transported.

Kerosene

All

l.B.2.a.iii.5

NA

NA

NA

NA

ND

ND

NA

product transported.

Table 4.2.4(continued)

Tier 1 emission factors for fugitive emissions (including venting and flaring) from oil and gas operations in developed countriesa'b

NA - Not Applicable ND - Not Determined a While the presented emission factors may all vary appreciably between countries, the greatest differences are expected to occur with respect to venting and flaring, particularly for oil production due to the potential for significant differences in the amount of gas conservation and utilisation practised.

b The range in values for fugitive emissions is attributed primarily to differences in the amount of process infrastructure (e.g. average number and sizes of facilities) per unit of gas throughput.

c "All" denotes all fugitive emissions as well as venting and flaring emissions.

11 "Fugitives" denotes all fugitive emissions including those from fugitive equipment leaks, storage losses, use of natural gas as the supply medium for gas-operated devices (e.g. instrument control loops, chemical injection pumps, compressor starters, etc.), and venting of still-column off-gas from glycol dehydrators. The presented range in values reflects the difference between fugitive emissions at offshore (the smaller value) and onshore (the larger value) emissions.

e "Flaring" denotes emissions from all continuous and emergency flare systems. The specific flaring rates may vary significantly between countries. Where actual flared volumes are known, these should be used to determine flaring emissions rather than applying the presented emission factors to production rates. The emission factors for direct estimation of CH4, C02 and N20 emissions from reported flared volumes are 0.012, 2.0 and 0.000023 Gg, respectively, per 106 m3 of gas flared based on a flaring efficiency of 98% and a typical gas analysis at a gas processing plant (i.e. 91.9% CH4, 0.58% C02, 0.68% N2 and 6.84% non-methane hydrocarbons by volume).

f The larger factor reflects the use of mostly reciprocating compressors on the system while the smaller factor reflects mostly centrifugal compressors.

* "Venting" denotes reported venting of waste associated and solution gas at oil production facilities and waste gas volumes from blowdown, purging and emergency relief events at gas facilities. Where actual vented volumes are known, these should be used to determine venting emissions rather than applying the presented emission factors to production rates. The emission factors for direct estimation of CH4 and C02 emissions from reported vented volumes are 0.66 and 0.0049 Gg, respectively, per 106 m3 of gas vented based on a typical gas analysis for gas transmission and distribution systems (i.e. 97.3% CH4, 0.26% C02, 1.7% N2 and 0.74% non-methane hydrocarbons by volume).

h While no factors are available for marine loading of offshore production for North America, Norwegian data indicate a CH4 emission factor of 1.0 to 3.6 Gg/103 m3 of oil transferred (derived from data provided by Norwegian Pollution Control Authority, 2000).

1 Estimated based on an aggregated emission factors for fugitive equipment leaks, fluid catalytic cracking and storage and handling of 0.53 kg/m3 (CPPI and Environment Canada, 1991), 0.6 kg/m3 ( lis EPA, 1995) and 0.2 g/kg (assuming the majority of the volatile products are stored in floating roof tanks with secondary seals) (EMEP/CORINAIR, 1996).

1 Estimated based on assumed average evaporation losses of 0.15 percent of throughput at the distribution terminal and additional losses of 0.15 percent of throughput at the retail outlet. These values will be much lower where Stage 1 and Stage 2 vapour recovery occurs and may be much greater in warm climates.

k NMVOC values are derived from methane values based on the ratio of the mass fractions of NMVOC to CH4. Values of 0.0144 kg/kg for gas transmission and distribution, 9.951 kg/kg for oil and condensate transportation and 0.3911 kg/kg for synthetic crude oil production are used.

1 The presented C02 emissions factors account for direct C02 emissions only, except for flaring, in which case the presented values account for the sum of direct C02 emissions and indirect contributions due to the atmospheric oxidation of gaseous non-C02 carbon emissions.

Sources: Canadian Association of Petroleum Producers (1999, 2004); API (2004); GRI/US EPA (1996); US EPA (1999).

Table 4.2.5

Tier 1 emission factors for fugitive emissions (including venting and flaring) from oil and gas operations in developing countries and countries with economies in transition3,1*

Category

Sub-categoryc

Code

CH,

co/

NMVOC

n2o

Units of measure

Value

Uncertainty (% of value)

Value

Uncertainty (% of value)

Value

Uncertainty (% of Value)

Value

Uncertainty (% of value)

Well Drilling

All

Flaring and Venting

l.B.2.a.ii or l.B.2.b.ii

+800%

±800%

±800%

ND

ND

Gg per 103 m3 total oil production

Well Testing

All

Flaring and Venting

l.B.2.a.ii or l.B.2.b.ii

+800%

±800%

±800%

6.8E-08 to 1.1E-06

-10 to ±1000%

Gg per 103 m3 total oil production

Well Servicing

All

Flaring and Venting

l.B.2.a.ii or l.B.2.b.ii

800%

±800%

±800%

ND

ND

Gg per 103 m3 total oil production

Production

All

Fugitives'1

l.B.2.b.iii.2

+250%

±250%

±250%

na

na

Gg per 106 m3 gas production

Flaring5

l.B.2.b.ii

7.6E-07 to 1.0E-06

±75%

1.2E-03 to 1.6E-03

±75%

6.2E-07 to 8.5E-07

±75%

2.1E-08 to 2.9E-08

-10 to ±1000%

Gg per 106 m3 gas production

Processing

Sweet Gas Plants

Fugitives

l.B.2.b.iii.3

+250%

±250%

±250%

na

NA

Gg per 106 m3 raw gas feed

Flaring

l.B.2.b.ii

1.2E-06 to 1.6E-06

±75%

1.8E-03 to 2.5E-03

±75%

9.6E-07 to 1.3E-06

±75%

2.5E-08 to 3.4E-08

-10 to ±1000%

Gg per 106 m3 raw gas feed

Sour Gas Plants

Fugitives

l.B.2.b.iii.3

±250%

±250%

±250%

NA

na

Gg per 106 m3 raw gas feed

Table 4.2.5(continued)

Tier 1 emission factors for fugitive emissions (including venting and flaring) from oil and gas operations in developing countries and countries with economies in transitiona'b

Category

Sub-category0

Code

CH,

co/

NMVOC

n2o

Units of measure

Value

Uncertainty (% of value)

Value

Uncertainty (% of value)

Value

Uncertainty (% of Value)

Value

Uncertainty (% of value)

Flaring

l.B.2.b.ii

2.4E-06 to 3.3E-06

±75%

3.6E-03 to 4.9E-03

±75%

1.9E-06 to 2.6E-06

±75%

5.4E-08 to 7.4E-08

-10 to ±1000%

Gg per 106m3 raw gas feed

Raw C02 Venting

l.B.2.b.i

NA

NA

6.3E-02 to 1.5E-01

-10 to ±1000%

NA

NA

NA

NA

Gg per 106m3 raw gas feed

Deep-cut

Extraction

Plants

(Straddle

Plants)

Fugitives

l.B.2.b.iii.3

+250%

+250%

+250%

NA

NA

Gg per 106m3 raw gas feed

Flaring

l.B.2.b.ii

7.2E-08 to 9.9E-08

±75%

1.1E-O4to 1.5E-04

±75%

5.9E-08 to 8.1E-08

±75%

1.2E-08 to 8.1E-08

-10 to ±1000%

Gg per 106m3 raw gas feed

Default

Weighted

Total

Fugitives

l.B.2.b.iii.3

+250%

+250%

+250%

NA

NA

Gg per 106m3 gas production

Flaring

l.B.2.b.ii

2.0E-06 to 2.8E-06

±75%

3.0E-03 to 4.1E-03

±75%

1.6E-06 to 2.2E-06

±75%

3.3E-08 to 4.5E-08

-10 to ±1000%

Gg per 106m3 gas production

Raw C02 Venting

l.B.2.b.i

NA

N/A

4.0E-02 to 9.5E-02

-10 to ±1000%

NA

N/A

NA

N/A

Gg per 106m3 gas production

Table 4.2.5(continued)

Tier 1 emission factors for fugitive emissions (including venting and flaring) from oil and gas operations in developing countries and countries with economies in transition3,1*

Category

Sub-categoryc

Code

CH,

co/

NMVOC

n2o

Units of measure

Value

Uncertainty (% of value)

Value

Uncertainty (% of value)

Value

Uncertainty (% of Value)

Value

Uncertainty (% of value)

Transmission & Storage

Transmission

Fugitives'

l.B.2.b.iii.4

+250%

+250%

+250%

NA

NA

Gg per 106m3 of marketable gas

Venting*

l.B.2.b.i

+250%

+250%

+250%

NA

NA

Gg per 106m3 of marketable gas

Storage

All

l.B.2.b.iii.4

2.5E-05 to 5.8E-05

-20 to +500%

1.1E-O7to 2.6E-07

-20 to +500%

3.6E-07 to 8.3E-07

-20 to +500%

ND

ND

Gg per 106m3 of marketable gas

Distribution

All

All

l.B.2.b.iii.5

1.1E-03 to 2.5E-03

-20 to +500%

5.1E-05 to 1.4E-04

-20 to +500%

1.6E-05 to 3.6E-5

-20 to +500%

ND

ND

Gg per 106m3 of utility sales

Natural Gas

Liquids

Transport

Condensate

All

l.B.2.a.iii.3

1.1E-04

-50 to +200%

7.2E-06

-50 to +200%

1.1E-03

-50 to +200%

ND

ND

Gg per 103 m3 Condensate and Pentanes Plus

Liquefied Petroleum Gas

All

l.B.2.a.iii.3

NA

NA

4.3E-04

+100%

ND

ND

2.2E-09

-10 to +1000%

Gg per 103 m3 LPG

Liquefied Natural Gas

All

l.B.2.a.iii.3

nd

ND

ND

ND

ND

ND

ND

ND

Gg per 106m3 of marketable gas

table 4.2.5(continued)

Tier 1 emission factors for fugitive emissions (including venting and flaring) from oil and gas operations in developing countries and countries with economies in transitiona'b

Category

Sub-category0

Code

CH,

CO/

NMVOC

n2o

Units of measure

Value

Uncertainty (% of value)

Value

Uncertainty (% of value)

Value

Uncertainty (% of Value)

Value

Uncertainty (% of value)

Production

Conventional Oil

Fugitives (Onshore)

l.B.2.a.iii.2

+800%

+800%

+800%

NA

NA

Gg per 103 m3 conventional oil production

Fugitives (Offshore)

l.

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