# 98.483 Calculating CO geologic sequestration.
You must calculate CO<sub>2</sub> sequestered using the following quantification principles from Clause 8.2 of CSA/ANSI ISO 27916:19 (incorporated by reference, see § 98.7).
(a) You must calculate the mass of CO<sub>2</sub> stored in association with CO<sub>2</sub>-EOR (*m*<sub>stored</sub>) in the reporting year by subtracting the mass of CO<sub>2</sub> loss from operations and the mass of CO<sub>2</sub> loss from the EOR complex from the total mass of CO<sub>2</sub> input (as specified in equation 1 to this paragraph (a)).
****Equation 1 to paragraph (a)
*m*<sub>stored</sub> = *m*<sub>input</sub>−*m*<sub>loss operations</sub>−*m*<sub>loss EOR complex</sub>
Where:
*m*<sub>stored</sub> = The annual quantity of associated storage in metric tons of CO<sub>2</sub> mass.
*m*<sub>input</sub> = The total mass of CO<sub>2</sub> *m*<sub>received</sub> by the EOR project plus *m*<sub>native</sub> (see Clause 8.3 of CSA/ANSI ISO 27916:19 (incorporated by reference, see § 98.7) and paragraph (c) of this section), metric tons. Native CO<sub>2</sub> produced and captured in the CO<sub>2</sub>-EOR project (*m*<sub>native</sub>) can be quantified and included in *m*<sub>input</sub>.
*m*<sub>loss operations</sub> = The total mass of CO<sub>2</sub> loss from project operations (see Clauses 8.4.1 through 8.4.5 of CSA/ANSI ISO 27916:19 (incorporated by reference, see § 98.7) and paragraph (d) of this section), metric tons.
*m*<sub>loss EOR complex</sub> = The total mass of CO<sub>2</sub> loss from the EOR complex (see Clause 8.4.6 of CSA/ANSI ISO 27916:19 (incorporated by reference, see § 98.7)), metric tons.
(b) The manner by which associated storage is quantified must assure completeness and preclude double counting. The annual mass of CO<sub>2</sub> that is recycled and reinjected into the EOR complex must not be quantified as associated storage. Loss from the CO<sub>2</sub> recycling facilities must be quantified.
(c) You must quantify the total mass of CO<sub>2</sub> input (*m*<sub>input</sub>) in the reporting year according to paragraphs (g)(1) through (3) of this section.
(1) You must include the total mass of CO<sub>2</sub> received at the custody transfer meter by the CO<sub>2</sub>-EOR project (*m*<sub>received</sub>).
(2) The CO<sub>2</sub> stream received (including CO<sub>2</sub> transferred from another CO<sub>2</sub>-EOR project) must be metered.
(i) The native CO<sub>2</sub> recovered and included as *m*<sub>native</sub> must be documented.
(ii) CO<sub>2</sub> delivered to multiple CO<sub>2</sub>-EOR projects must be allocated among those CO<sub>2</sub>-EOR projects.
(3) The sum of the quantities of allocated CO<sub>2</sub> must not exceed the total quantities of CO<sub>2</sub> received.
(d) You must calculate the total mass of CO<sub>2</sub> from project operations (*m*<sub>loss operations</sub>) in the reporting year as specified in equation 2 to this paragraph (d).
****Equation 2 to paragraph (d)
Where:
*m*<sub>loss leakage facilities</sub> = Loss of CO<sub>2</sub> due to leakage from production, handling, and recycling CO<sub>2</sub>-EOR facilities (infrastructure including wellheads), metric tons.
*m*<sub>loss vent/flare</sub> = Loss of CO<sub>2</sub> from venting/flaring from production operations, metric tons.
*m*<sub>loss entrained</sub> = Loss of CO<sub>2</sub> due to entrainment within produced gas/oil/water when this CO<sub>2</sub> is not separated and reinjected, metric tons.
*m*<sub>loss transfer</sub>=Loss of CO<sub>2</sub> due to any transfer of CO<sub>2</sub> outside the CO<sub>2</sub>-EOR project, metric tons. You must quantify any CO<sub>2</sub> that is subsequently produced from the EOR complex and transferred offsite.