Tracers are unique or highly indicative chemical species that can be used to "fingerprint" the CO2Carbon dioxide of interest and distinguish it from other sources. Chemical tracers, both natural and introduced, can be used for potential leakage(in CO2Carbon dioxide storage) The escape of injected fluid from the storage formationA body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it to the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) or water column detection. Utilisation of tracers requires the availability of a number of boreholes in and around the injectionThe process of using pressure to force fluids down wells plume.
Naturally occurring chemical constituents, such as stable isotopes of C, H, O, or S, can be used to assess fluid origin, detect CO2Carbon dioxide migrationThe movement of fluids in reservoir rocks or leakage(in CO2Carbon dioxide storage) The escape of injected fluid from the storage formationA body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it to the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) or water column into the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) and assess interaction with host rocks along flow paths (Cole et al., 20042004 - D.R. Cole, J. Horita, M.C. van Soest, B.M. Kennedy, M.F. MoreaGas chemistry and isotopic monitoring during the CO2 injection test at Lost Hills, CA.see more). A variety of sampling and analytical approaches are available, including direct extraction from flux chambers, simple or complex soil gas wells, and sorbent approaches. Analysis can be done in the laboratory or via various types of field instruments. The isotopic composition of carbon and oxygen in the injected CO2Carbon dioxide (if different from the ambient CO2Carbon dioxide), as wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injectionThe process of using pressure to force fluids down wells of fluids as minor entrained impurities, can be used to distinguish injected CO2Carbon dioxide from ambient CO2Carbon dioxide. These constituents, however, are not conservative and, hence, as CO2Carbon dioxide moves though rock/fluid/soil/ecosystem, the ratios of isotopes and entrained constituents will be modified, giving a record of the reaction pathway.
Phase-partitioning tracers could be used to determine the amount of immobile phases (such as the residual oil in a petroleum reservoirA subsurface body of rock with sufficient porosityMeasure for the amount of pore spaceSpace between rock or sediment grains that can contain fluids in a rock and permeabilityAbility to flow or transmit fluids through a porous solid such as rock to store and transmit fluids) and to estimate the amount of residual gas trapping(CO2Carbon dioxide) ContainmentRestriction of the movement of a fluid to a designated volume (e.g. reservoir) or immobilisation of CO2Carbon dioxide, there are four main trapping mechanisms: structural or stratigraphicThe order and relative position of geological strata trapping; residual CO2Carbon dioxide trapping (capillary trappingImmobilisation of a fraction of in-situ fluids by capillary forces) by capillary forces; solubility trappingA process in which fluids are retained by dissolution in liquids naturally present by dissolution of CO2Carbon dioxide in resident formationA body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it fluids forming a non-buoyant fluid; and mineral trapping where CO2Carbon dioxide is absorbed by solid minerals present in the storage(CO2Carbon dioxide) A process for retaining captured CO2Carbon dioxide, so that it does not reach the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) volume that has taken place. Residual gas trapping(CO2Carbon dioxide) ContainmentRestriction of the movement of a fluid to a designated volume (e.g. reservoir) or immobilisation of CO2Carbon dioxide, there are four main trapping mechanisms: structural or stratigraphicThe order and relative position of geological strata trapping; residual CO2Carbon dioxide trapping (capillary trappingImmobilisation of a fraction of in-situ fluids by capillary forces) by capillary forces; solubility trappingA process in which fluids are retained by dissolution in liquids naturally present by dissolution of CO2Carbon dioxide in resident formationA body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it fluids forming a non-buoyant fluid; and mineral trapping where CO2Carbon dioxide is absorbed by solid minerals present in the storage(CO2Carbon dioxide) A process for retaining captured CO2Carbon dioxide, so that it does not reach the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) volume is an important parameter for estimating long-term storage(CO2Carbon dioxide) A process for retaining captured CO2Carbon dioxide, so that it does not reach the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) integrity.
Tracers employed in CO2Carbon dioxide storage(CO2Carbon dioxide) A process for retaining captured CO2Carbon dioxide, so that it does not reach the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) projects have included noble gases and perfluorocarbon tracers (PFTs) (Nimz and Hudson, 20052005 - G. Nimz and G. HudsonThe use of noble gas isotopes for monitoring leakage of geologically stored CO2, Carbon Dioxide Capture for Storage in Deep Geologic Formations—Results from the CO2 Capture Project, v. 2: Geologic Storage of Carbon Dioxide with Monitoring and Verification SM Bensonsee more; Fahrner et al., 20122012 - S. Fahrner, D. Schäfer, A. DahmkeA monitoring strategy to detect CO2 intrusion in deeper freshwater aquiferssee more). The occurrence of these chemicals in natural systems is so low that detection and attribution may be done at parts-per-billion detection (e.g. Jeandel et al., 20102010 - E. Jeandel, A. Battani and P. SardaLessons learned from natural and industrial analogues for storage of carbon dioxidesee more). Many introduced tracers (PFTs, SF6) are benign in water and ecosystems, but are powerful greenhouse gasses. They, therefore, need to be used conservatively. Due to low detection limits, contamination is a serious riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event. Thus, it is important to use best practices to inject tracers (separate handling for injectionThe process of using pressure to force fluids down wells and detection). Natural tracers are known to have complex reactions with rock, water, and soil, requiring a fairly sophisticated approach to reach a correct interpretation. For this reason, more knowledge is required with regards to the interaction of introduced tracers with water, different rock types, soil, and organic material.