Hydraulic fracturing is a method which is commonly used in shaleClay that has changed into a rock due to geological processes gas production and is also used in methane production from coal seams (e.g. Wo et al., 2005). The method is applied to artificially create fractures in the reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids rock (in that case a shaleClay that has changed into a rock due to geological processes or coal seam) in order to increase its permeabilityAbility to flow or transmit fluids through a porous solid such as rock. The risks of fracturing in relation to geological storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere of CO2Carbon dioxide are somewhat different in the two applications. These are therefore treated separately below.
It is possible that the reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids of a shaleClay that has changed into a rock due to geological processes gas producing geological unit is part of the caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir of a geological storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere of CO2Carbon dioxide. Hydraulic fracturing in connection to shaleClay that has changed into a rock due to geological processes gas exploration and extraction is an example of conflict of interest since hydraulic fracturing will increase the permeabilityAbility to flow or transmit fluids through a porous solid such as rock of the caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir. Therefore, an increased riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event of leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column from the CO2Carbon dioxide storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere site might be expected, if there is gas shaleClay that has changed into a rock due to geological processes production in the caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir.
Methane production and/or geological storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere of CO2Carbon dioxide in deep coal seams may include fracturing of the coal bed in order to increase the permeabilityAbility to flow or transmit fluids through a porous solid such as rock. During this process there is a riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event that fractures could extend into the caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir, decreasing cap rock integrity. However, hydraulic fractures are artificially created, and their extension can therefore to some extent be controlled. The vertical extension of hydraulic fractures is dependent on in-situ stress state of the bedrock, elastic moduli of the bedrock, fractureAny break in rock along which no significant movement has occurred toughness, formationA body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it leak-off pressure and fluid flow. The growth of vertical fractures can be modelled using linear elastic fractureAny break in rock along which no significant movement has occurred models and the risks can be reduced if the propagation of the fractures can be monitored (Wo et al., 2005).
During methane production, methane is desorbed from the coal. This process may cause shrinkage of the coal reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids volume and affect the overlying bedrock integrity (Wo et al., 2005), which may either be the caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir of a coal seam CO2Carbon dioxide storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere site or form part of the sealing formations for CO2Carbon dioxide storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere in, for instance, a deep saline aquiferA deep underground rock formation composed of permeable materials and containing highly saline fluids.
If the amount of injected CO2Carbon dioxide is greater than the storage capacityThe accumulated mass of CO2 that can be stored environmentally safely, i.e., without causing leakage of CO2 or native reservoir fluids or triggering geologic activity that has a negative impact on human health or the environment of the reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids, dissolute CO2Carbon dioxide may be transported from the storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere complex by natural fluid flow to areas where the geological conditions are less wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids known and potential leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column pathways may not have been identified. This migrationThe movement of fluids in reservoir rocks event may happen if storage capacityThe accumulated mass of CO2 that can be stored environmentally safely, i.e., without causing leakage of CO2 or native reservoir fluids or triggering geologic activity that has a negative impact on human health or the environment of the reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids has been grossly underestimated during the initial site characterisation process. However, a wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids-functioning monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions program during injectionThe process of using pressure to force fluids down wells will detect if the movements of the CO2 plumeDispersing volume of CO2-rich phase contained in target formation goes beyond the anticipated reservoirA subsurface body of rock with sufficient porosity and permeability to store and transmit fluids and injectionThe process of using pressure to force fluids down wells can be stopped. The CGSCO2 Geological Storage; Injection accompanied by storage of CO2 streams in underground geological formations. Europe Key Report 1 provides an extensive review of monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions techniques. However, it should be noted that through the detailed geoscientific surveys undertaken during the site characterisation stage of the storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere life cycle, storage capacityThe accumulated mass of CO2 that can be stored environmentally safely, i.e., without causing leakage of CO2 or native reservoir fluids or triggering geologic activity that has a negative impact on human health or the environment and the minimum capacity in particular should be wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids known so migrationThe movement of fluids in reservoir rocks out of the storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere complex should not occur.