The quality and integrity of caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir preventing leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column from the reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids is no less important than good reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids properties for effective CO2Carbon dioxide storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere. This is especially relevant for insufficiently explored saline aquiferAn underground layer of fluid-bearing permeable rock or unconsolidated materials (gravel, sand, or silt) with significant permeability to allow flow structures.
CaprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir quality and integrity (i.e. whether it would be an impermeable barrier for trapped CO2Carbon dioxide for millennia) can be assessed using information from wells (drill cores, wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids logging) and seismic data, as in the case of reservoirs. Although the study methods are usually site specific, in general the following analyses are applied to evaluate caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir structures (Chadwick et al., 20062006 - R. A. Chadwick, O. Eiken, P. Williamson, G. WilliamsGeophysical monitoring of the CO2 plume at Sleipner, North Sea: an outline reviewsee more):
- permeabilityAbility to flow or transmit fluids through a porous solid such as rock and threshold capillary entry pressureAdditional pressure needed for a liquid or gas to enter a pore and overcome surface tension measurements on drill core samples;
- analyses of mineralogical composition (minerals important for CO2Carbon dioxide-brine-rock interaction, e.g. carbonates, to a lesser extent albite, chloriteA magnesium-iron aluminosilicate sheet silicate clay mineral, muscovite, etc.) of drill core samples;
- pore water analyses in order to assess pore water origin of drill core samples;
- caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir reactivity (with CO2Carbon dioxide and brine) laboratory analyses of drill core samples and modelling;
- evaluation of seismic sections and maps in order to identify faults within and above the principal caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir and/or facies changes within the caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir;
- evaluation/modelling of fault(geology) A surface at which strata are no longer continuous, but are found displaced properties within and above the principal caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir (tightness/stress/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 likelihood).