# 40 CFR § 98.443 - Calculating CO2 geologic sequestration.

§ 98.443 Calculating CO2 geologic sequestration.

You must calculate the mass of CO2 received using CO2 received equations (Equations RR-1 to RR-3 of this section), unless you follow the procedures in § 98.444(a)(4). You must calculate CO2 sequestered using injection equations (Equations RR-4 to RR-6 of this section), production/recycling equations (Equations RR-7 to RR-9 of this section), surface leakage equations (Equation RR-10 of this section), and sequestration equations (Equations RR-11 and RR-12 of this section). For your first year of reporting, you must calculate CO2 sequestered starting from the date set forth in your approved MRV plan.

(a) You must calculate and report the annual mass of CO2 received by pipeline using the procedures in paragraphs (a)(1) or (a)(2) of this section and the procedures in paragraph (a)(3) of this section, if applicable.

(1) For a mass flow meter, you must calculate the total annual mass of CO2 in a CO2 stream received in metric tons by multiplying the mass flow by the CO2 concentration in the flow, according to Equation RR-1 of this section. You must collect these data quarterly. Mass flow and concentration data measurements must be made in accordance with § 98.444.

${\mathrm{CO}}_{2T,r}=\sum _{p=1}^{4}\left({Q}_{r,p}-{S}_{r,p}\right)*{C}_{{\mathrm{CO}}_{2,p,r}}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-1)}$

where:
CO2T,r = Net annual mass of CO2 received through flow meter r (metric tons).
Qr,p = Quarterly mass flow through a receiving flow meter r in quarter p (metric tons).
Sr,p = Quarterly mass flow through a receiving flow meter r that is redelivered to another facility without being injected into your well in quarter p (metric tons).
CCO2,p,r = Quarterly CO2 concentration measurement in flow for flow meter r in quarter p (wt. percent CO2, expressed as a decimal fraction).
p = Quarter of the year.
r = Receiving flow meter.

(2) For a volumetric flow meter, you must calculate the total annual mass of CO2 in a CO2 stream received in metric tons by multiplying the volumetric flow at standard conditions by the CO2 concentration in the flow and the density of CO2 at standard conditions, according to Equation RR-2 of this section. You must collect these data quarterly. Volumetric flow and concentration data measurements must be made in accordance with § 98.444.

${\mathrm{CO}}_{2T,r}=\sum _{p=1}^{4}\left({Q}_{r,p}-{S}_{r,p}\right)*{D*C}_{{\mathrm{CO}}_{2,p,r}}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-2)}$

where:
CO2T,r = Net annual mass of CO2 received through flow meter r (metric tons).
Qr,p = Quarterly volumetric flow through a receiving flow meter r in quarter p at standard conditions (standard cubic meters).
Sr,p = Quarterly volumetric flow through a receiving flow meter r that is redelivered to another facility without being injected into your well in quarter p (standard cubic meters).
D = Density of CO2 at standard conditions (metric tons per standard cubic meter): 0.0018682.
CCO2,p,r = Quarterly CO2 concentration measurement in flow for flow meter r in quarter p (vol. percent CO2, expressed as a decimal fraction).
p = Quarter of the year.
r = Receiving flow meter.

(3) If you receive CO2 through more than one flow meter, you must sum the mass of all CO2 received in accordance with the procedure specified in Equation RR-3 of this section.

${\mathrm{CO}}_{2}=\sum _{r=1}^{R}{\mathrm{CO}}_{2T,r}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-3)}$

where:
CO2 = Total net annual mass of CO2 received (metric tons).
CO2T,r = Net annual mass of CO2 received (metric tons) as calculated in Equation RR-1 or RR-2 for flow meter r.
r = Receiving flow meter.

(b) You must calculate and report the annual mass of CO2 received in containers using the procedures in paragraphs (b)(1) or (b)(2) of this section.

(1) If you are measuring the mass of contents in a container under the provisions of § 98.444(a)(2)(i), you must calculate the CO2 received for injection in containers using Equation RR-1 of this section.

where:
CO2T,r = Net annual mass of CO2 received in containers r (metric tons).
CCO2,p,r = Quarterly CO2 concentration measurement of contents in containers r in quarter p (wt. percent CO2, expressed as a decimal fraction).
Qr,p = Quarterly mass of contents in containers r in quarter p (metric tons).
Sr,p = Quarterly volume of contents in containers r redelivered to another facility without being injected into your well in quarter p (standard cubic meters).
p = Quarter of the year.
r = Containers.

(2) If you are measuring the volume of contents in a container under the provisions of § 98.444(a)(2)(ii), you must calculate the CO2 received for injection in containers using Equation RR-2 of this section.

where:
CO2T,r = Net annual mass of CO2 received in containers r (metric tons).
CCO2,p,r = Quarterly CO2 concentration measurement of contents in containers r in quarter p (vol. percent CO2, expressed as a decimal fraction).
Qr,p = Quarterly volume of contents in containers r in quarter p (standard cubic meters).
Sr,p = Quarterly mass of contents in containers r redelivered to another facility without being injected into your well in quarter p (metric tons).
D = Density of the CO2 received in containers at standard conditions (metric tons per standard cubic meter):0.0018682.
p = Quarter of the year.
r = Containers.

(c) You must report the annual mass of CO2 injected in accordance with the procedures specified in paragraphs (c)(1) through (c)(3) of this section.

(1) If you use a mass flow meter to measure the flow of an injected CO2 stream, you must calculate annually the total mass of CO2 (in metric tons) in the CO2 stream injected each year in metric tons by multiplying the mass flow by the CO2 concentration in the flow, according to Equation RR-4 of this section. Mass flow and concentration data measurements must be made in accordance with § 98.444.

${\mathrm{CO}}_{2,u}=\sum _{p=1}^{4}{Q}_{p,u}*{C}_{{CO}_{2,p,u}}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-4)}$

where:
CO2,u = Annual CO2 mass injected (metric tons) as measured by flow meter u.
Qp,u = Quarterly mass flow rate measurement for flow meter u in quarter p (metric tons per quarter).
CCO2,p,u = Quarterly CO2 concentration measurement in flow for flow meter u in quarter p (wt. percent CO2, expressed as a decimal fraction).
p = Quarter of the year.
u = Flow meter.

(2) If you use a volumetric flow meter to measure the flow of an injected CO2 stream, you must calculate annually the total mass of CO2 (in metric tons) in the CO2 stream injected each year in metric tons by multiplying the volumetric flow at standard conditions by the CO2 concentration in the flow and the density of CO2 at standard conditions, according to Equation RR-5 of this section. Volumetric flow and concentration data measurements must be made in accordance with § 98.444.

${\mathrm{CO}}_{2,u}=\sum _{p=1}^{4}{Q}_{p,u}*{D*C}_{{CO}_{2,p,u}}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-5)}$

where:
CO2,u = Annual CO2 mass injected (metric tons) as measured by flow meter u.
Qp,u = Quarterly volumetric flow rate measurement for flow meter u in quarter p at standard conditions (standard cubic meters per quarter).
D = Density of CO2 at standard conditions (metric tons per standard cubic meter): 0.0018682.
CCO2,p,u = CO2 concentration measurement in flow for flow meter u in quarter p (vol. percent CO2, expressed as a decimal fraction).
p = Quarter of the year.
u = Flow meter.

(3) To aggregate injection data for all wells covered under this subpart, you must sum the mass of all CO2 injected through all injection wells in accordance with the procedure specified in Equation RR-6 of this section.

${\mathrm{CO}}_{2I}=\sum _{u=1}^{U}{\mathrm{CO}}_{2,u}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-6)}$

where:
CO2. = Total annual CO2 mass injected (metric tons) through all injection wells.
CO2,u = Annual CO2 mass injected (metric tons) as measured by flow meter u.
u = Flow meter.

(d) You must calculate the annual mass of CO2 produced from oil or gas production wells or from other fluid wells for each separator that sends a stream of gas into a recycle or end use system in accordance with the procedures specified in paragraphs (d)(1) through (d)(3) of this section. You must account for any CO2 that is produced and not processed through a separator. You must account only for wells that produce the CO2 that was injected into the well or wells covered by this source category.

(1) For each gas-liquid separator for which flow is measured using a mass flow meter, you must calculate annually the total mass of CO2 produced from an oil or other fluid stream in metric tons that is separated from the fluid by multiplying the mass gas flow by the CO2 concentration in the gas flow, according to Equation RR-7 of this section. You must collect these data quarterly. Mass flow and concentration data measurements must be made in accordance with § 98.444.

${\mathrm{CO}}_{2,w}=\sum _{p=1}^{4}{Q}_{p,w}{*C}_{{CO}_{2,p,w}}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-7)}$

Where:
CO2,w = Annual CO2 mass produced (metric tons) through separator w.
Qp,w = Quarterly gas mass flow rate measurement for separator w in quarter p (metric tons).
CCO2,p,w = Quarterly CO2 concentration measurement in flow for separator w in quarter p (wt. percent CO2, expressed as a decimal fraction).
p = Quarter of the year.
w = Separator.

(2) For each gas-liquid separator for which flow is measured using a volumetric flow meter, you must calculate annually the total mass of CO2 produced from an oil or other fluid stream in metric tons that is separated from the fluid by multiplying the volumetric gas flow at standard conditions by the CO2 concentration in the gas flow and the density of CO2 at standard conditions, according to Equation RR-8 of this section. You must collect these data quarterly. Volumetric flow and concentration data measurements must be made in accordance with § 98.444.

${\mathrm{CO}}_{2,w}=\sum _{p=1}^{4}{Q}_{p,w}{*D*C}_{{CO}_{2,p,w}}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-8)}$

Where:
CO2,w = Annual CO2 mass produced (metric tons) through separator w.
Qp,w = Volumetric gas flow rate measurement for separator w in quarter p at standard conditions (standard cubic meters).
D = Density of CO2 at standard conditions (metric tons per standard cubic meter): 0.0018682.
CCO2,p,w = CO2 concentration measurement in flow for separator w in quarter p (vol. percent CO2, expressed as a decimal fraction).
p = Quarter of the year.
w = Separator.

(3) To aggregate production data, you must sum the mass of all of the CO2 separated at each gas-liquid separator in accordance with the procedure specified in Equation RR-9 of this section. You must assume that the total CO2 measured at the separator(s) represents a percentage of the total CO2 produced. In order to account for the percentage of CO2 produced that is estimated to remain with the produced oil or other fluid, you must multiply the quarterly mass of CO2 measured at the separator(s) by a percentage estimated using a methodology in your approved MRV plan. If fluids containing CO2 from injection wells covered under this source category are produced and not processed through a gas-liquid separator, the concentration of CO2 in the produced fluids must be measured at a flow meter located prior to reinjection or reuse using methods in § 98.444(f)(1). The considerations you intend to use to calculate CO2 from produced fluids for the mass balance equation must be described in your approved MRV plan in accordance with § 98.448(a)(5).

${\mathrm{CO}}_{2P}-\left(1+X\right)*\sum _{w=1}^{W}{\mathrm{CO}}_{2,w}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-9)}$

Where:
CO2. = Total annual CO2 mass produced (metric tons) through all separators in the reporting year.
CO2,w = Annual CO2 mass produced (metric tons) through separator w in the reporting year.
X = Entrained CO2 in produced oil or other fluid divided by the CO2 separated through all separators in the reporting year (weight percent CO2, expressed as a decimal fraction).
w = Separator.

(e) You must report the annual mass of CO2 that is emitted by surface leakage in accordance with your approved MRV plan. You must calculate the total annual mass of CO2 emitted from all leakage pathways in accordance with the procedure specified in Equation RR-10 of this section.

${\mathrm{CO}}_{2E}=\sum _{x=1}^{X}{\mathrm{CO}}_{2,x}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-10)}$

where:
CO2. = Total annual CO2 mass emitted by surface leakage (metric tons) in the reporting year.
CO2,x = Annual CO2 mass emitted (metric tons) at leakage pathway x in the reporting year.
x = Leakage pathway.

(f) You must report the annual mass of CO2 that is sequestered in subsurface geologic formations in the reporting year in accordance with the procedures specified in paragraphs (f)(1) and (f)(2) of this section.

(1) If you are actively producing oil or natural gas or if you are producing any other fluids, you must calculate the annual mass of CO2 that is sequestered in the underground subsurface formation in the reporting year in accordance with the procedure specified in Equation RR-11 of this section.

${\mathrm{CO}}_{2}={\mathrm{CO}}_{2I}-{\mathrm{CO}}_{2P}-{\mathrm{CO}}_{2E}-{\mathrm{CO}}_{2\mathrm{FI}}-{\mathrm{CO}}_{2\mathrm{FP}}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-11)}$

where:
CO2 = Total annual CO2 mass sequestered in subsurface geologic formations (metric tons) at the facility in the reporting year.
CO2. = Total annual CO2 mass injected (metric tons) in the well or group of wells covered by this source category in the reporting year.
CO2P = Total annual CO2 mass produced (metric tons) in the reporting year.
CO2. = Total annual CO2 mass emitted (metric tons) by surface leakage in the reporting year.
CO2FI = Total annual CO2 mass emitted (metric tons) from equipment leaks and vented emissions of CO2 from equipment located on the surface between the flow meter used to measure injection quantity and the injection wellhead, for which a calculation procedure is provided in subpart W of this part.
CO2FP = Total annual CO2 mass emitted (metric tons) from equipment leaks and vented emissions of CO2 from equipment located on the surface between the production wellhead and the flow meter used to measure production quantity, for which a calculation procedure is provided in subpart W of this part.

(2) If you are not actively producing oil or natural gas or any other fluids, you must calculate the annual mass of CO2 that is sequestered in subsurface geologic formations in the reporting year in accordance with the procedures specified in Equation RR-12 of this section.

${\mathrm{CO}}_{2}={\mathrm{CO}}_{2I}-{\mathrm{CO}}_{2E}-{\mathrm{CO}}_{2\mathrm{FI}}\phantom{\rule{0ex}{0ex}}\text{(Eq. RR-12)}$

where:
CO2 = Total annual CO2 mass sequestered in subsurface geologic formations (metric tons) at the facility in the reporting year.
CO2. = Total annual CO2 mass injected (metric tons) in the well or group of wells covered by this source category in the reporting year.
CO2. = Total annual CO2 mass emitted (metric tons) by surface leakage in the reporting year.
CO2FI = Total annual CO2 mass emitted (metric tons) from equipment leaks and vented emissions of CO2 from equipment located on the surface between the flow meter used to measure injection quantity and the injection wellhead, for which a calculation procedure is provided in subpart W of this part.
[75 FR 75078, Dec. 1, 2010, as amended at 76 FR 73906, Nov. 29, 2011; 78 FR 71978, Nov. 29, 2013]