Saline Aquifers
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2021 ◽  
Geovani Christopher Kaeng ◽  
Kate Evans ◽  
Florence Bebb ◽  
Rebecca Head

Abstract CO2 migration and trapping in saline aquifers involves the injection of a non-wetting fluid that displaces the in-situ brine, a process that is often termed ‘drainage’ in reservoir flow dynamics. With respect to simulation, however, this process is more typical of regional basin modelling and percolating hydrocarbon migration. In this study, we applied the invasion percolation method commonly used in hydrocarbon migration modelling to the CO2 injection operation at the Sleipner storage site. We applied a CO2 migration model that was simulated using a modified invasion percolation algorithm, based upon the Young-Laplace principle of fluid flow. This algorithm assumes that migration occurs in a state of capillary equilibrium in a flow regime dominated by buoyancy (driving) and capillary (restrictive) forces. Entrapment occurs when rock capillary threshold pressure exceeds fluid buoyancy pressure. Leaking occurs when fluid buoyancy pressure exceeds rock capillary threshold pressure. This is now widely understood to be an accurate description of basin-scale hydrocarbon migration and reservoir filling. The geological and geophysical analysis of the Sleipner CO2 plume anatomy, as observed from the seismic data, suggested that the distribution of CO2 was strongly affected by the geological heterogeneity of the storage formation. In the simulation model, the geological heterogeneity were honored by taking the original resolution of the seismic volume as the base grid. The model was then run at an ultra-fast simulation time in a matter of seconds or minutes per realization, which allowed multiple scenarios to be performed for uncertainty analysis. It was then calibrated to the CO2 plume distribution observed on seismic, and achieved an accurate match. The paper establishes that the physical principle of CO2 flow dynamics follows the Young-Laplace flow physics. It is then argued that this method is most suitable for the regional site screening and characterization, as well as for site-specific injectivity and containment analysis in saline aquifers.

Earth ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 894-919
Giuliana Vinci ◽  
Lucia Maddaloni ◽  
Leo Mancini ◽  
Sabrina Antonia Prencipe ◽  
Marco Ruggeri ◽  

According to the United Nations (2020), since the 1980s, the global overall rate of water use has grown by 1% per year, and it is projected that, by 2050, humanity’s water footprint could exceed 30% of current levels. This situation is in stark contrast to the path toward the Sustainable Development Goals, especially Goal 6, “clean water and sanitation”, which also influences Goal 14, “life below water”, and Goal 15, “life on land”. This is because the availability of water directly affects the food security and production capacity of each Country, and therefore its management is a crucial issue worthy of particular attention. Problems related to water security are particularly evident in the Mediterranean area, which is already facing high environmental challenges. It is an area severely affected by global warming; thus, it is one of the most vulnerable environments to climate change globally. It follows that the improper management of water resources could further worsen an already alarming situation. This research aims to study the main water-related challenges that Mediterranean Countries face, highlighting the significant problems that weaken each Country. In this regard, the indicators relating to Goal 6 were considered, to define each Country’s current state. However, for a correct understanding, the main problems these Countries face were researched through a critical review of the literature (Scopus, Google Scholar, Web of Science). In this way, we were able to underline the effects of human activities on the hydrosphere and the repercussions on various ecosystems, following the drivers-pressures-state-impact-response causal framework. The results suggest that there is still a long way for Mediterranean Countries to progress toward Agenda 2030, as they face problems related to chemical (nitrate, microplastics, heavy metals, pesticides, etc.) and biological (E. coli and other microorganisms) pollution, as well as saline aquifers, absent or obsolete infrastructures, and transboundary basins. Hence, this study aims to provide valuable tools for a better evaluation of water management in Mediterranean Countries.

2021 ◽  
Vol 11 (20) ◽  
pp. 9759
Changhyup Park ◽  
Jaehwan Oh ◽  
Suryeom Jo ◽  
Ilsik Jang ◽  
Kun Sang Lee

This paper presents a Pareto-based multi-objective optimization for operating CO2 sequestration with a multi-well system under geological uncertainty; the optimal well allocation, i.e., the optimal allocation of CO2 rates at injection wells, is obtained when there is minimum operation pressure as well as maximum sequestration efficiency. The distance-based generalized sensitivity analysis evaluates the influence of geological uncertainty on the amount of CO2 sequestration through four injection wells at 3D heterogeneous saline aquifers. The spatial properties significantly influencing the trapping volume, in descending order of influence, are mean sandstone porosity, mean sandstone permeability, shale volume ratio, and the Dykstra–Parsons coefficient of permeability. This confirms the importance of storable capacity and heterogeneity in quantitatively analyzing the trapping mechanisms. Multi-objective optimization involves the use of two aquifer models relevant to heterogeneity; one is highly heterogeneous and the other is less so. The optimal well allocations converge to non-dominated solutions and result in a large injection through one specific well, which generates the wide spread of a highly mobile CO2 plume. As the aquifer becomes heterogeneous with a large shale volume and a high Dykstra–Parsons coefficient, the trapping performances of the combined structural and residual sequestration plateau relatively early. The results discuss the effects of spatial heterogeneity on achieving CO2 geological storage, and they provide an operation strategy including multi-objective optimization.

2021 ◽  
pp. petgeo2020-117
Giampaolo Proietti ◽  
Marko Cvetković ◽  
Bruno Saftić ◽  
Alessia Conti ◽  
Valentina Romano ◽  

One of the most innovative and effective technologies developed in recent decades for reducing carbon dioxide emissions to the atmosphere is CCS (Carbon Capture & Storage). It consists of capture, transport and injection of CO2 produced by energy production plants or other industries. The injection takes place in deep geological formations with the suitable geometrical and petrophysical characteristics to permanently trap CO2 in the subsurface, which is called geological storage. In the development process of a potential geological storage site, correct capacity estimation of the injectable volumes of CO2 is one of the most important aspects. There are various approaches to estimate CO2 storage capacities for potential traps, including geometrical equations, dynamic modelling, numerical modelling, and 3D modelling. In this work, generation of three-dimensional petrophysical models and equations for calculation of the storage volumesare used to estimate the effective storage capacity of four potential saline aquifers in the Adriatic Sea offshore. The results show how different saline aquifers, with different lithologies at favourable depths, can host a fair amount of CO2, that will imply a further and more detailed feasibility studies for each of these structures. A detailed analysis is carried out for each saline aquifer identified, varying the parameters of each structure identified, and adapting them for a realistic estimate of potential geological storage capacity.Thematic collection: This article is part of the Geoscience for CO2 storage collection available at:

N. Heinemann ◽  
J. Scafidi ◽  
G. Pickup ◽  
E.M. Thaysen ◽  
A. Hassanpouryouzband ◽  

2021 ◽  
Vol 3 ◽  
Yashvardhan Verma ◽  
Vikram Vishal ◽  
P. G. Ranjith

In order to tackle the exponential rise in global CO2 emissions, the Intergovernmental Panel on Climate Change (IPCC) proposed a carbon budget of 2,900 Gt to limit the rise in global temperature levels to 2°C above the pre-industrial level. Apart from curbing our emissions, carbon sequestration can play a significant role in meeting these ambitious goals. More than 500 Gt of CO2 will need to be stored underground by the end of this century to make a meaningful impact. Global capacity for CO2 storage far exceeds this requirement, the majority of which resides in unexplored deep aquifers. To identify potential storage sites and quantify their storage capacities, prospective aquifers or reservoirs need to be screened based on properties that affect the retention of CO2 in porous rocks. Apart from the total volume of a reservoir, the storage potential is largely constrained by an increase in pore pressure during the early years of injection and by migration of the CO2 plume in the long term. The reservoir properties affect both the pressure buildup and the plume front below the caprock. However, not many studies have quantified these effects. The current analysis computes the effect of rock properties (porosity, permeability, permeability anisotropy, pore compressibility, and formation water salinity) and injection rate on both these parameters by simulating CO2 injection at the bottom of a 2D mesh grid with hydrostatic boundary conditions. The study found that the most significant property in the sensitivity analysis was permeability. Porosity too affected the CO2 plume migration substantially, with higher porosities considerably delaying horizontal and vertical migration. Injection rate impacted both the pressure rise and plume migration consistently. Thus, in screening potential storage sites, we can infer that permeability is the dominant criterion when the pore pressure is closer to the minimum principal stress in the rocks, due to which injection rate needs to be managed with greater caution. Porosity is more significant when the lateral extents of the reservoir limit the storage potential.

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