5.3.5 Reactive transport

The intense flushing of the reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids rock around CO2Carbon dioxide injectors with large quantities of dried super critical CO2Carbon dioxide can cause desiccation of the remaining brine in the pore spaceSpace between rock or sediment grains that can contain fluids, leading to substantial precipitation of salts and sulphate minerals, blocking the pores and diminished injectivityA measure of the rate at which a quantity of fluid can be injected into a well. On the other hand, carbonateNatural minerals (e.g. calcite, dolomite, siderite, limestone) composed of various anions bonded to a CO32- cation dissolution by the acidified brine could cause porosityMeasure for the amount of pore space in a rock and permeabilityAbility to flow or transmit fluids through a porous solid such as rock to increase.

Both precipitation and dissolution can cause geomechanical effects, given that large pressure variations can occur close to the injector. Although Thermal-Hydraulic-Chemical (THC) codes present many advantages in forecasting injectionThe process of using pressure to force fluids down wells flow rates or chemical processes, they only consider interactions between minerals and aqueous phases. THC codes do not integrate the mechanical deformation involved in CO2Carbon dioxide injectionThe process of using pressure to force fluids down wells. For the time being, fully coupled thermal-hydraulic-chemical-mechanical codes are still in the development stage. The first simulations, with external coupling between the reactive transport model and geomechanical model, give encouraging results. Johnson et al. (2005) simulated long-term caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir integrity as a function of geochemical and geomechanical contributions to permeabilityAbility to flow or transmit fluids through a porous solid such as rock evolution using the reactive transport simulator NUFT and distinct-element geomechanical model LDEC (Gaus et al., 20082008 - I. Gaus, P. Audigane, L. André, J. Lions, N. Jacquemet, P. Durst, I. Czernichowski-Lauriol and M. AzaroualGeochemical and solute transport modelling for CO2 storage, what to expect from it?see more).

Li et al., 20062006 - Q. Li, Z. Wu, Y. Bai, X. Yin and X. LiThermo-hydro-mechanical Modeling of CO2 Sequestration System Around Fault Environmentsee more built a model that uses a sequential coupling approach to investigate the thermo-hydro-mechanical behaviour of CO2Carbon dioxide injectionThe process of using pressure to force fluids down wells around a fault(geology) A surface at which strata are no longer continuous, but are found displaced environment. The effects of temperature, initial geological stress, injectionThe process of using pressure to force fluids down wells pressure and CO2Carbon dioxide buoyancyTendency of a fluid or solid to rise through a fluid of higher density on the mechanical behaviour of the fault(geology) A surface at which strata are no longer continuous, but are found displaced were studied. The injectionThe process of using pressure to force fluids down wells pressure has a larger influence on the relative slip change of the fault(geology) A surface at which strata are no longer continuous, but are found displaced than the buoyancyTendency of a fluid or solid to rise through a fluid of higher density induced by the CO2 plumeDispersing volume of CO2-rich phase contained in target formation. Although at the initial stage of the injectionThe process of using pressure to force fluids down wells the pore pressure of the storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere formations is affected by the injectionThe process of using pressure to force fluids down wells pressure, as time passes, the CO2 plumeDispersing volume of CO2-rich phase contained in target formation-induced buoyancyTendency of a fluid or solid to rise through a fluid of higher density plays a key role, influencing the pore pressure of the storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere system.

Heffer et al., 20072007 - K. Heffer, X. Zhang, N. Koutsabeloulis, I. Main and L. LiIdentification of activated (Therefore Potentially Conductive) faults and fractures through statistical correlations in production and injection rates and coupled flow-geomechanical modellingsee more suggested that statistical modelling using the principal component analysis of wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids rate fluctuations can be used to identify the faults that are mechanically active during project development. Coupled geomechanical-flow models were used to demonstrate the observed correlations between rate and fault(geology) A surface at which strata are no longer continuous, but are found displaced-related characteristics.

Chang and Bryant, 20092009 - K. W. Chang and S. L. BryantThe Effect of Faults on Dynamics of CO2 Plumessee more studied the effects of declined and inclined faults on the behaviour of CO2Carbon dioxide plumes in 2D and 3D Formations. Several fault(geology) A surface at which strata are no longer continuous, but are found displaced properties (conductive vs. sealing, angle relative to dip(geology) The steepest angle of descent of a tilted rock strata or feature relative to a horizontal plane, distance from initial plume location) were examined to understand the dynamics of CO2Carbon dioxide behaviour such as residual phase trapping(CO2) Containment or immobilisation of CO2, there are four main trapping mechanisms: structural or stratigraphic trapping; residual CO2 trapping (capillary trapping) by capillary forces; solubility trapping by dissolution of CO2 in resident formation fluids forming a non-buoyant fluid; and mineral trapping where CO2 is absorbed by solid minerals present in the storage volume and direction of the plume. They stated that a large amount of CO2Carbon dioxide leaks into the fault(geology) A surface at which strata are no longer continuous, but are found displaced below the top sealAn impermeable rock that forms a barrier above and around a 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 such that fluids are held in the 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. However, the fault(geology) A surface at which strata are no longer continuous, but are found displaced also creates a virtual sourceAny process, activity or mechanism that releases a greenhouse gasGas in the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) that absorbs and emits infrared radiation emitted by the Earth’s surface, the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%), and clouds; thus, trapping heat within the surface-troposphere system. e.g. water vapour (H2O), carbon dioxide (CO2Carbon dioxide), nitrous oxide (N2O), methane (CH4), ozone (O3), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs), an aerosol, or a precursor thereof into the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) for up-dip(geology) The steepest angle of descent of a tilted rock strata or feature relative to a horizontal plane migrationThe movement of fluids in reservoir rocks into the permeable bed. This attenuates the 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 and results in significant additional residual saturationThe fraction of the injected CO2Carbon dioxide that is trapped in pores by capillary forces 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, as can be seen in Fig. 5-7.