Canada’s Air Pollutant Emissions Inventory Report 2022: annex 2.2

A2.2 Estimation methodologies for Oil and Gas Industry by sector/subsector

Refined Petroleum Products Bulk Storage and Distribution (under Downstream Oil And Gas Industry)

Description

Refined Petroleum Products Bulk Storage and Distribution covers fugitive volatile organic compound (VOC) emissions from bulk distribution terminals and bulk plants. It includes volatile components of fuels that are emitted as fuel moves from the refinery to the end-user, whenever tanks are filled or emptied or while tanks are open to the atmosphere, be the large above-ground tanks, tank trucks, or railcars. In addition, the subsector includes emissions that result from the evaporation of fuels spilled during transfer operations.

Only fugitive VOC emissions from bulk plants are estimated in-house.

General inventory method

Pollutant(s) estimated:
VOCs

Emissions are calculated using the gross sales of gasoline for on-road motor vehicles multiplied by emission factors developed by Tecsult Inc (2006).

Activity data

Gross sales of gasoline for motor vehicles: Statistics Canada (n.d.[a])

Emission factors (EF)

Study on gasoline vapour recovery in Stage 1 distribution networks in Canada: Tecsult Inc (2006)

Natural Gas Distribution (under Downstream Oil and Gas Industry)

Description

Natural Gas Distribution includes emissions from all infrastructure used to receive high-pressure natural gas from transmission pipelines and then reduce the pressure for distribution to end-users. This sector consists of distribution pipelines (distribution mains and service lines) and measurement and regulation stations, up to and including customer meters.

Emissions from related construction activities, ancillary structures and operations (buildings, offices, etc.), and mobile sources are included under the Construction Operations, Commercial and Institutional Fuel Combustion, and Transportation and Mobile Equipment sources (respectively) of the Air Pollutant Emissions Inventory (APEI).

General inventory method

Pollutant(s) estimated:
TPM, PM₁₀, PM_2.5, SO_x, NO_x, VOCs, CO, NH₃

Emission estimates are generated using data from comprehensive inventories (EC, 2014; CAPP, 2005a) and extrapolated (CAPP, 2005b) from 2012 onwards based on pipeline length.

Activity data

Gas Pipeline Distance, by province: Statistics Canada (2021)

Emission factors (EF)

EC (2014)

Natural Gas Transmission and Storage (under Upstream Oil and Gas Industry)

Description

Natural Gas Transmission includes emissions from all infrastructure used to transport pipeline quality natural gas to local distribution companies. This sector consists of large diameter pipelines, compressor stations and metering facilities. Natural Gas Storage includes emissions from all infrastructure used to store natural gas produced during off-peak times (i.e. summer) for delivery during peak demand periods (i.e. winter). Gas is stored in spent production fields, aquifers or salt caverns with facilities consisting of piping, meters, compressor stations and dehydrators.

Emissions from midstream services (e.g. straddle plants) and gas plants are included under Natural Gas Production and Processing. Emissions from related construction activities, ancillary structures and operations (buildings, offices, etc.) and mobile sources are included under the Construction Operations, Commercial and Institutional Fuel Combustion, and Transportation and Mobile Equipment sources (respectively) of the APEI.

General inventory method

Pollutant(s) estimated:
TPM, PM₁₀, PM_2.5, SO_x, NO_x, VOCs, CO, NH₃

Emission estimates are generated using data from comprehensive inventories (EC, 2014; CAPP, 2005a) and extrapolated (CAPP, 2005b) from 2012 onwards. Natural gas transmission emissions are extrapolated based on pipeline length, while natural gas storage emissions are extrapolated based on annual volumes of gas injected and withdrawn.

Activity data

Gas Pipeline Distance, by province: Statistics Canada (2021)

Natural gas injections to storage and withdrawals from storage: Statistics Canada (n.d.[b])

Emission factors (EF)

EC (2014)

Upstream Oil and Gas Industry

Description

Upstream Oil and Gas Industry includes emissions from all infrastructure used to locate, extract, produce, process/treat and transport natural gas, crude oil (light/medium oil, heavy oil, crude bitumen), liquefied petroleum gas (LPG) and condensate to market. It also includes emissions from onshore and offshore facilities, as well as drilling and exploration, conventional oil and gas production, open pit mining and in situ oil sands production, natural gas processing and oil transmission. Specifically, it includes the following subsectors:

• Accidents and Equipment Failures
• Disposal and Waste Treatment
• Heavy Crude Oil Cold Production
• Light/Medium Crude Oil Production
• Natural Gas Production and Processing
• Oil Sands In-Situ Extraction
• Petroleum Liquids Transportation
• Well Drilling/Servicing/Testing

Emissions from related construction activities, ancillary structures and operations (buildings, offices, etc.), and mobile sources are included under the Construction Operations, Commercial and Institutional Fuel Combustion, and Transportation and Mobile Equipment sources (respectively) of the APEI.

General inventory method

Pollutant(s) estimated:
TPM, PM₁₀, PM_2.5, SO_x, NO_x, VOCs, CO, NH₃

Emission estimates are generated using data from comprehensive inventories (EC, 2014; CAPP, 2005a) and are extrapolated (CAPP, 2005b) from 2012 onwards using various provincial-level activity data.

Alberta reported venting and flaring emissions are calculated directly (i.e. not extrapolated) for the years 2010 to 2020 using monthly conventional volumetric data (Petrinex, 2021) and detailed gas composition data for each township in Alberta (Tyner and Johnson, 2020).

Saskatchewan reported venting and flaring emissions are calculated directly for the years 1990 to 2020 using reported vent and flare volumes (SKMER, 2021a) and detailed gas composition data by five production classes^{Footnote 1} provided by the Saskatchewan Ministry of Energy and Resources (SKMER, 2021b).

Alberta and British Columbia VOC emissions from surface casing vent flow (SCVF) are calculated directly for 1990 to 2020 from provincial SCVF incidence reports (AER, 2021e; BCOGC, 2021c). Reports for each detected SCVF are linked to provincial oil and gas well information (AER, 2021f; BCOGC, 2021d, 2021e), which provides key dates and characteristics of the wells where SCVF has occurred. Location information for wells in Alberta allows specific township-level gas composition data (Tyner and Johnson, 2020) to be applied to SCVF releases, while the composition of SCVF releases in British Columbia is derived from representative Alberta data. This information is combined to estimate the magnitude and duration of these releases, then annual emissions are aggregated and allocated to the appropriate Upstream Oil and Gas subsector.

Activity data

Spills and accidents: AER (2021a), BCOGC (2021a), CNLOPB (2021a), MB (2021), and SKMER (2021c)
Wells drilled: CAPP (2021)
Operating wells: CAPP (2021) and CNLOPB (2021b, 2021c, 2021d, 2021e, 2021f)
Reported volumes of gas flared and vented: AER (2020), BC (2019), BCOGC (2020, 2021b), CNLOPB, (2021g), Petrinex (2021) and SKMER (2021a)
Fuel gas volumes: AER (2021b), BC (2019), BCOGC (2021b) and SKMER (2021a)
In-situ bitumen production volumes: AER (2021c)
Non-associated natural gas production volumes: CER (2021)
Crude oil and natural gas production volumes: NBERD (2021), SKMER (2021d, 2021e) and Statistics Canada (n.d.[c], n.d.[d], n.d.[e], n.d.[f])
Natural gas shrinkage: AER (2021d) and BC (2021)
Alberta monthly conventional volumetric data: Petrinex (2021b)
Alberta and British Columbia SCVF: AER (2021e, 2021f) and BCOGC (2021c, 2021d, 2021e)

In addition to the extrapolated estimates, the SO_x estimates for Alberta Natural Gas Processing are adjusted to account for regulations that were developed after the model was originally created. The adjustments are made using both historical provincial data and National Pollutant Release Inventory (NPRI) data up to 2005. From 2006 onwards, NPRI data for Alberta SO_x emissions from gas plants are used due to the complete facility coverage. NPRI data for the Atlantic provinces are used in place of the model estimates due to the complete facility coverage for the region. Additionally, extrapolated estimates for the Oil Sands In-Situ Extraction facilities are reconciled with NPRI data to eliminate double-counting. NPRI data for Oil Sands Mining, Extraction and Upgrading are used due to the complete facility coverage of the subsector.

Emission factors (EF)

EC (2014)

Alberta flaring emissions from 2010 to 2020 are calculated using the monthly conventional volumetric data (Petrinex, 2021) and emission factors calculated from the detailed gas composition data (Tyner and Johnson, 2020) by Alberta township. Similarly, Saskatchewan flaring emissions from 1990 to 2020 are calculated using flare volumes by production class and EFs calculated from gas composition data (SKMER 2021a). The flaring SO₂ emission factors are calculated as shown in Equation A2-2.1.

Equation A2–2.1

EF_SO2,i=∑_j ((y_(i,j)∙n_(s,j)∙ MW_SO2)/V_STP) ∙g_c

where:

EF_SO2,i = volume-weighted SO₂ emission factor for area i (g/m³)</span>

y_i,j = mole fraction of component j in area i

n_s,j = number of sulphur atoms per molecule of component j

MW_SO2 = molecular weight of SO_2, (g/mol) = 64.066 g/mol

V_STP = volume of gas at standard conditions (101.325 kPa and 15°C) = 23.6444813 m³/kmol

g_c = constant of proportionality = 1000 mol/kmol

The VOC emission factor is calculated as shown in Equation A2-2.2.

Equation A2–2.2

EF_i,j = ∑_j (y_i,j∙MW_j∙(1-CE)/V_STP) ∙ g_c

where:

EF_i,j = emission factor for area i and VOC component j (g/m³)

MW_j = molecular weight of VOC component j (g/mol)

CE = combustion efficiency = 0.98 (EC, 2014)

Flaring emission factors for NO_x, CO, PM_2.5, PM₁₀ and TPM are calculated using Equation A2-2.3.

Equation A2–2.3

EF_i,j = ER_j∙HHV_i

where:

EF_i,j = emission factor for area i and pollutant j (g/m³)

ER_j = flaring emission rate for pollutant j (g/MJ)

HHV_i = higher heating value for area i (MJ/m³)

The flaring emission rates for NO_x, CO, PM_2.5, PM₁₀ and TPM are as follows:

Reported venting emissions for Alberta from 2010 to 2020 and Saskatchewan from 1990 to 2020 are calculated using the vented volumes and detailed gas composition data as shown in Equation A2-2.4.

Equation A2–2.4

Emis_i,j=y_i,j∙Vol_i∙ρ_j

where:

Emis_i,j = vented emissions of component j in area i (kt)

y_i,j = mole fraction of component j in area i

Vol_i = volume of gas vented in area i (10³ m³)

p_j = density of component j at standard conditions (101.325 kPa and 15°C) (kg/m³)

Lastly, VOC emissions from SCVF in Alberta and British Columbia are determined using reported total gas release rates. In cases where SCVF is reported without a gas flow rate, average flow rates are applied based on well location and SCVF characteristics. The product of the total gas flow rate and the estimated duration gives the volume of gas released, which is then used to calculate VOC emissions using Equation A2-2.4.

References, Annex 2.2, Estimation methodologies for Oil and Gas Industry by sector/subsector

[AER] Alberta Energy Regulator. 2020. Upstream petroleum industry flaring and venting report. Calgary (AB): Alberta Energy Regulator. 76 pp. [PDF]

[AER] Alberta Energy Regulator. 2021a. Compliance dashboard – Incidents. Retrieved [accessed 2021 Oct 15].

[AER] Alberta Energy Regulator. 2021b. VPR6800 supply and disposition of gas (economics) [last updated 2021 Jan 26]. Unpublished data. Calgary (AB): Alberta Energy Regulator.

[AER] Alberta Energy Regulator. 2021c. Alberta’s energy reserves and supply/demand outlook [revised 2021 May; cited 2021 Oct 26]. Calgary (AB): Alberta Energy Regulator.

[AER] Alberta Energy Regulator. 2021d. Alberta energy resource industries monthly statistics, gas supply and disposition [revised 2021 Apr 15; cited 2021 Oct 14]. Calgary (AB): Alberta Energy Regulator.

[AER] Alberta Energy Regulator. 2021e. Well vent flow/gas migration report [cited 2021 Aug 16]. Calgary (AB): Alberta Energy Regulator.

[AER] Alberta Energy Regulator. 2021f. Well infrastructure report (Petrinex) [cited 2021 Aug 16]. Calgary (AB): Alberta Energy Regulator.

[BC] British Columbia Government. 2019. Production and distribution of natural gas in BC [accessed 2019 Jul 5].

[BCOGC] British Columbia Oil and Gas Commission. 2020. Air summary report [accessed 2020 Jan 30]. Technical Report. Commission Offices (BC): BCOGC. [PDF]

[BCOGC] British Columbia Oil and Gas Commission. 2021a. Drilling kicks and blowouts by area [accessed 2021 Oct 5].

[BCOGC] British Columbia Oil and Gas Commission. 2021b. 2019-2020 volumetric Petrinex data [received 2021 Jul 30]. Prepared for Environment and Climate Change Canada.

[BCOGC] British Columbia Oil and Gas Commission. 2021c. Surface casing vent flow database [accessed 2021 Nov 18].

[BCOGC] British Columbia Oil and Gas Commission. 2021d. Well index report [accessed 2021 April 7].

[BCOGC] British Columbia Oil and Gas Commission. 2021e. Well surface abandonment report [accessed 2021 Sept 27].

[CAPP] Canadian Association of Petroleum Producers. 2005a. A national inventory of greenhouse gas (GHG), criteria air contaminant (CAC) and hydrogen sulphide (H₂S) emissions by the upstream oil and gas industry, Vols 1–5. Calgary (AB): Clearstone Engineering Ltd.

[CAPP] Canadian Association of Petroleum Producers. 2005b. Extrapolation of the 2000 UOG emission inventory to 2001, 2002 and 2003. Calgary (AB): Clearstone Engineering Ltd.

[CAPP] Canadian Association of Petroleum Producers. 2021. Statistical handbook for Canada’s upstream petroleum industry [accessed 2021 Oct 25]. Calgary (AB): CAPP.

[CER] Canada Energy Regulator. 2021. Canada’s energy future 2020 [accessed 2021 Oct 1].

[CNLOPB] Canada-Newfoundland and Labrador Offshore Petroleum Board. 2021a. Environment statistics: Spill frequency and volume annual summary [last updated 2021 Jan 7; accessed 2021 Oct 21]. [PDF]

[CNLOPB] Canada-Newfoundland and Labrador Offshore Petroleum Board. 2021b. Production summary by well – Hebron [last updated 2021 Jan 18; accessed 2021 Octl 21]. [PDF]

[CNLOPB] Canada-Newfoundland and Labrador Offshore Petroleum Board. 2021c. Production summary by well – Hibernia [last updated 2021 Jan 27; accessed 2021 Oct 21]. [PDF]

[CNLOPB] Canada-Newfoundland and Labrador Offshore Petroleum Board. 2021d. Production summary by well – North Amethyst [last updated 2021 Jan 15; accessed 2021 Oct 21]. [PDF]

[CNLOPB] Canada-Newfoundland and Labrador Offshore Petroleum Board. 2021e. Production summary by well – Terra Nova [last updated 2021 Jan 19; accessed 2021 Oct 21]. [PDF]

[CNLOPB] Canada-Newfoundland and Labrador Offshore Petroleum Board. 2021f. Production summary by well – White Rose [last updated 2021 Jan 15; accessed 2021 Oct 21]. [PDF]

[CNLOPB] Canada-Newfoundland and Labrador Offshore Petroleum Board. 2021g. Monthly gas flaring [accessed 2021 Sep 20]. Unpublished report. Provided to Environment and Climate Change Canada.

[EC] Environment Canada. 2014. Technical report on Canada’s upstream oil and gas industry, Vols. 1–4. Calgary (AB): Clearstone Engineering Ltd. Prepared for Environment Canada.

[MB] Manitoba Government. 2021. Petroleum industry spill statistics [last updated 2021 Sep 15; accessed 2021 Oct 6].

[NBERD] New Brunswick Energy and Resource Development. 2021. Monthly production statistics [accessed 2021 Oct 18]. [PDF]

Petrinex. 2021. Petrinex: Canada’s Petroleum Information Network. Alberta Public Data - Monthly Conventional Volumetric Data [accessed 2021 Jul 13].

[SKMER] Saskatchewan Ministry of Energy and Resources. 2021a. Gas composition by production class [accessed 2021 Jul 13]. Unpublished report. Provided to Environment and Climate Change Canada.

[SKMER] Saskatchewan Ministry of Energy and Resources. 2021b. Saskatchewan fuel, flare and vent [revised 2021 Feb; accessed 2021 Jul 16].

[SKMER] Saskatchewan Ministry of Energy and Resources. 2021c. Saskatchewan upstream oil and gas IRIS incident report [revised 2021 Sep 29; accessed 2021 Oct 5].

[SKMER] Saskatchewan Ministry of Energy and Resources. 2021d. 2020 crude oil volume and value summary [last updated 2021 Jul 8; accessed 2021 Jul 12].

[SKMER] Saskatchewan Ministry of Energy and Resources. 2021e. 2020 natural gas volume and value summary [last updated 2021 Jul 8; accessed 2021 Jul 12].

Statistics Canada. No date(a). Report on energy supply and demand in Canada. Catalogue No. 57 003 X.

Statistics Canada. No date(b). Table 25-10-0057-01 (formerly CANSIM 129-0005) Canadian natural gas storage, Canada and provinces, monthly(database).

Statistics Canada. No date(c). Table 25-10-0014-01 (formerly CANSIM 126-0001) Crude oil and equivalent, monthly supply and disposition.

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Statistics Canada. No date(f). Table 25-10-0063-01 (formerly CANSIM 126-0003) Supply and disposition of crude oil and equivalent.

Statistics Canada. 2021. Gas pipeline distance, by province [accessed 2021 Nov]. Unpublished report. Provided to Environment and Climate Change Canada.

Tecsult Inc. 2006. Study on gasoline vapour recovery in Stage I distribution networks in Canada. Report No. 0514676. Prepared for Environment Canada.

Tyner D and Johnson M. 2020. Improving upstream oil and gas emissions estimates with updated gas composition data. Carleton University (ON): Energy and Emissions Research Laboratory (EERL). Prepared for Environment and Climate Change Canada.