ISO 27916:2019 二酸化炭素の回収、輸送、地質学的貯蔵—石油増進回収（CO2-EOR）を使用した二酸化炭素の貯蔵 | ページ 6

3.1

anthropogenic carbon dioxide

carbon dioxide that is initially produced as a by-product of a combustion, chemical, or separation process (including separation of hydrocarbon-bearing fluids or gases) where it would otherwise be emitted to the atmosphere (excluding the recycling of non-anthropogenic CO₂)

Note 1 to entry: The chemical symbol “CO₂” is synonymous with “carbon dioxide”. Accordingly, the two ways of writing out “carbon dioxide” and “CO₂” are used interchangeably in this document.

Note 2 to entry: If CO₂ that meets the definition of anthropogenic CO₂ is not included in a supplemental quantification of associated storage of anthropogenic CO₂ (e.g., because it was received and injected by a CO₂-EOR project prior to the quantification period) it will generally be treated as non-anthropogenic CO₂ in that quantification.

3.2

associated storage

co₂ stored in association with co₂-EOR (3.4) that occurs as an inherent result of a dedicated hydrocarbon production operation

Note 1 to entry: The requirements of this document are intended to ensure that CO₂ stored in association with a CO₂-EOR operation is stored as effectively as CO₂ stored in a geologic storage operation that complies with ISO 27914.

3.3

authority

competent governmental entity or entities with legal power to regulate or permit co₂-EOR (3.4) , to regulate storage of CO₂ in association with a co₂-EOR (3.4) operation, or to regulate quantification of the storage of CO₂ in association with a co₂-EOR (3.4) operation

3.4

co₂ enhanced oil recovery

co₂-EOR

process designed to produce hydrocarbons from a reservoir using the injection of CO₂

Note 1 to entry: The process of CO₂ enhanced oil recovery is explained in detail in Annex A

3.5

co₂ enhanced oil recovery project

co₂-EOR project

EOR complex (3.10) , underground equipment, wells, surface or above seabed equipment, activities and rights necessary to an enhanced oil recovery operation, including any necessary or required surface or subsurface rights regulated by the authority

3.6

co₂ injection well

well used to inject CO₂ into a project reservoir (3.19)

3.7

co₂ stream

stream consisting overwhelmingly of carbon dioxide

Note 1 to entry: The CO₂ stream typically includes impurities and may include substances added to the stream to improve performance of hydrocarbon recovery operation and/or to facilitate CO₂ detection.

[SOURCE:ISO 27917:2017, 3.2.10, modified — Note revised to added “to improve performance of hydrocarbon recovery operation”.]

3.8

containment

status of CO₂ being confined within the EOR complex (3.10) by an effective trap (3.23) or combination of traps

3.9

containment assurance

demonstration that the features and geologic structure of the co₂-EOR project (3.5) are adequate to provide safe, long-term (3.21) containment (3.8) of CO₂, and that the CO₂ flood is operated in a way to assure containment of the CO₂ in the EOR complex (3.10)

3.10

EOR complex

project reservoir (3.19) , trap (3.23) , and such additional surrounding volume in the subsurface as defined by the operator (3.16) within which injected CO₂ will remain in safe, long-term (3.21) containment (3.8)

3.11

injection-withdrawal ratio

ratio, during a defined period, of the volume of all fluids and gases injected into the project reservoir (3.19) to the volume of all fluids and gases produced from the project reservoir as determined using consistent temperature and pressure conditions

3.12

leakage

unintended release of CO₂ to the atmosphere or out of the EOR complex (3.10)

[SOURCE:ISO 27917:2017, 3.2.14, modified — Added to the atmosphere or out of the EOR complex.]

3.13

leakage pathway

geological or artificial conduit for leakage (3.12) of CO₂ out of the EOR complex (3.10)

3.14

loss

leakage (3.12) , intended releases, and transfers of CO₂ from the co₂-EOR project (3.5)

3.15

native CO₂

co₂ present and indigenous within the project reservoir (3.19) prior to hydrocarbon production or any CO₂ injection

Note 1 to entry: Native CO₂ is also known as “in situ CO₂”.

3.16

operator

entity responsible for the co₂-EOR project (3.5)

3.17

plug & abandon

permanently close a well or wellbore to prevent inter-formational movement of fluids into strata, into freshwater aquifers, and out of the well

Note 1 to entry: In most cases, a series of cement plugs is set in the wellbore, with an inflow or integrity test made at each stage to confirm hydraulic isolation.

3.18

post-termination

period of time after termination (3.22)

3.19

project reservoir

geologic reservoir in to which CO₂ is injected for production of hydrocarbons in paying or commercial quantities

3.20

quantification period

period of time during which associated storage (3.2) is being quantified

3.21

safe, long-term

period necessary for associated storage (3.2) to be considered environmentally safe by the system under which the quantification is being implemented

3.22

termination

process beginning with the cessation of quantification of associated storage (3.2) , and ending with both the termination of hydrocarbon production from the project reservoir (3.19) , and the plugging & abandonment of wells unless otherwise required by the authority (3.3)

3.23

trap

any feature or mechanism that alone or in combination provides safe, long-term (3.21) containment (3.8) below a low-permeability confining geologic layer (cap rock or seal), including in the pore spaces of the EOR complex (3.10) (physical, stratigraphic, or structural trapping), by capillary pressure from the water in the pore spaces between the rock (residual trapping), by dissolution in the in situ formation fluids (solubility), by hydrodynamic trapping, by adsorption onto organic matter or by reacting in geologic formations to produce minerals (geochemical trapping)