Geologic carbon storage is considered as a requisite to effectively mitigate climate change, so large amounts of carbon dioxide (CO2) are expected to be injected in sedimentary saline formations. CO2 injection leads to the creation of acidic solution when it dissolves into the resident brine, which can react with reservoir rock, especially carbonates. We numerically investigated the behavior of reservoir-caprock system where CO2 injection-induced changes in the hydraulic and geomechanical properties of Apulian limestone were measured in the laboratory. We found that porosity of the limestone slightly decreases after CO2 treatment, which lead to a permeability reduction by a factor of two. In the treated specimens, calcite dissolution was observed at the inlet, but carbonate precipitation occurred at the outlet, which was closed during the reaction time of three days. Additionally, the relative permeability curves were modified after CO2–rock interaction, especially the one for water, which evolved from a quadratic to a quasi-linear function of the water saturation degree. Geomechanically, the limestone became softer and it was weakened after being altered by CO2. Simulation results showed that the property changes occurring within the CO2 plume caused a stress redistribution because CO2 treated limestone became softer and tended to deform more in response to pressure buildup than the pristine rock. The reduction in strength induced by geochemical reactions may eventually cause shear failure within the CO2 plume affected rock. This combination of laboratory experiments with numerical simulations leads to a better understanding of the implications of coupled chemo-mechanical interactions in geologic carbon storage.
#1Víctor Vilarrasa(CSIC: Spanish National Research Council)H-Index: 23
#2Roman Y. Makhnenko(UIUC: University of Illinois at Urbana–Champaign)H-Index: 12
Abstract CO 2 leakage is a major concern for geologic carbon storage. To assess the caprock sealing capacity and the strength of faults, we test in the laboratory the rock types involved in CO 2 storage at representative in-situ conditions. We use the measured parameters as input data to a numerical model that simulates CO 2 injection in a deep saline aquifer bounded by a low-permeable fault. We find that the caprock sealing capacity is maintained and that, even if a fault undergoes a series of ...
#1Víctor Vilarrasa(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 23
#2Roman Y. Makhnenko(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 12
Last. Sohrab Gheibi(NTNU: Norwegian University of Science and Technology)H-Index: 5
view all 3 authors...
Abstract Large amounts of carbon dioxide (CO2) should be injected in deep saline formations to mitigate climate change, implying geomechanical challenges that require further understanding. Pressure build-up induced by CO2 injection will decrease the effective stresses and may affect fault stability. Geomechanical effects of overpressure induced by CO2 injection either in the hanging wall or in the foot wall on fault stability are investigated. CO2 injection in the presence of a low-permeable fa...
In December 2015, member states of the United Nations Framework Convention on Climate Change (UNFCCC) adopted the Paris Agreement, which aims to hold the increase in the global average temperature to below 2°C and to pursue efforts to limit the temperature increase to 1.5°C. The Paris Agreement requires that anthropogenic greenhouse gas emission sources and sinks are balanced by the second half of this century. Because some nonzero sources are unavoidable, this leads to the abstract concept of “...
In situ rock is often saturated with fluid, the presence of which affects both elastic parameters and inelastic deformation processes. Techniques were developed for testing fluid-saturated porous rock under the limiting conditions of drained (long-term), undrained (short-term) and unjacketed (solid matrix) response in hydrostatic, axisymmetric and plane-strain compression. Drained and undrained poroelastic parameters, including bulk modulus, Biot and Skempton coefficients, of Berea sandstone wer...
Abstract Due to the corrosive nature of dissolved CO2, the potential short or long term alteration of rock properties, represents a major issue in several sites where natural CO2 circulation is observed, as well as in reservoirs targeted for storage of anthropogenic CO2. To date, this has been primarily studied from a transport-chemical perspective, with laboratory evidence of microstructural modifications together with the consequences for flow properties. Compared to the transport-chemical asp...
This study investigates the stress-dependency of relative permeability in rock fractures. Previous studies provide contradictory evidence of the influence of increasing stress on the relative permeability of fractures. Some studies suggest that irreducible water saturation increases, while others show the reverse. In an attempt to resolve these differences, laboratory core flooding experiments are applied to measure the relative permeability of nitrogen–water mixtures in a fracture under various...
Carbonatic rocks, such as calcarenites, are very often subject to damage processes, causing a progressive degradation of their mechanical properties. In nature, in some cases, this phenomenon can cause the collapse of cliffs and underground cavities, with dangerous consequences for the anthropic environment. In this paper, the results of an experimental campaign, intended to both clarify and quantify the mechanical consequences of this process, are illustrated. To achieve such a goal, suitable p...
Abstract Enhanced oil recovery by CO2 injection (CO2-EOR) is a tertiary oil recovery process which has a prospective for being used, at the same time, as an effective technique for carbon dioxide storage. There is a huge potential for additional oil production and CO2 storage in the North Sea depleted chalk reservoirs. North Sea chalk is characterized by high porosity but also high specific surface causing low permeability. A high porosity provides room for CO2 storage, while a high specific sur...
Abstract Geological carbon dioxide storage must be designed such that the CO 2 cannot escape from the rock formation into which it is injected, and often simple stratigraphic trapping is insufficient. CO 2 can be trapped in the pore space as droplets surrounded by water through capillary trapping. X-ray microtomography was used to image, at a resolution of 6.6 μm, the pore-scale arrangement of these droplets in three carbonates and two sandstones. The pressures and temperatures in the pore space...
#2Víctor Vilarrasa(UPC: Polytechnic University of Catalonia)H-Index: 23
Last. Tobias S. Rötting(UPC: Polytechnic University of Catalonia)H-Index: 18
view all 6 authors...
Abstract CO2 injection and storage in deep saline aquifers involves many coupled processes, including multiphase flow, heat and mass transport, rock deformation and mineral precipitation and dissolution. Coupling is especially critical in carbonate aquifers, where minerals will tend to dissolve in response to the dissolution of CO2 into the brine. The resulting neutralization will drive further dissolution of both CO2 and calcite. This suggests that large cavities may be formed and that proper s...
Abstract null null Cementitious grouts are a vital component for the economically-viable implementation of the geological storage of CO2 in providing an engineered long-term seal. In this study a class G cement was carbonated at 80 bar, at either 60 °C or 120 °C, whilst immersed in a synthetic brine for durations of up to 5 months. X-ray computed tomography was used to evaluate the advancement of carbonation depth, whilst SEM/EDXA and XRD were used to characterise microstructural alteration of t...
#2Shanpo Jia(CUMT: China University of Mining and Technology)
Last. Lingdong Meng(Northeast Petroleum University)H-Index: 1
view all 5 authors...
The rapidly increasing demand for the consumption of natural gas has attracted the interests to store natural gas in aquifer reservoir. However, natural gas injected into the aquifer reservoir, which could cause ground surface deformation and mechanical integrity destruction of caprock. Taking the aquifer gas storage of S trap as the research object, according to the geological structure and hydrogeological information, a coupling large-scale hydromechanical model is established to evaluate the ...
#1Kiseok Kim(UIUC: University of Illinois at Urbana–Champaign)H-Index: 3
#2Roman Y. Makhnenko(UIUC: University of Illinois at Urbana–Champaign)H-Index: 12
Proper characterization of the mechanical and flow properties of participating rock formations is crucial for subsurface geo-energy projects, including hydrocarbon extraction, geologic carbon storage, and enhanced geothermal systems. Application of mechanical and hydraulic pressures changes the porosity of rock and modifies flow paths. For low-permeable or “tight” rock that mainly contains nanoscale pores and serves as the confining layer for underground storage operations, a significant change ...
Abstract This article studies the individual contribution of each term in the Navier-Stokes-Darcy (Brinkman) equation to the fluid linear momentum balance and the consequences of opting for the Darcy or Brinkman equations in 3D reactive flow simulations of a vuggy carbonate. A two-scale continuum model was used to simulate the acidification of a carbonate sample using the Darcy and Brinkman equations. Rock heterogeneity is considered in the initial porosity and permeability fields, which are cal...
#1Kiseok Kim(UIUC: University of Illinois at Urbana–Champaign)H-Index: 3
#2Roman Y. Makhnenko(UIUC: University of Illinois at Urbana–Champaign)H-Index: 12
Injection of CO2 into the subsurface requires consideration of the poromechanical behavior of reservoir rock saturated with aqueous fluid. The material response is usually assumed to be elastic, to avoid consideration of induced seismicity, or viscoelastic, if long-term deformations are needed to be taken into the account. Both elastic and viscous behavior may be influenced by the chemical reactions that are caused by the acidic mixture formed as high-pressure CO2 enters the pore space saturated...
Abstract CO2 reinjection in petroleum reservoirs brings advantages in oil production but may cause dissolution in carbonate reservoirs. Two-scale continuum models have been successfully used to simulate acidification. However, the use of realistic porosity and permeability fields in mesh simulations is still a challenge, in such a way that uniform and normal distributions have been used to generate these fields in the past. The main objective of this work was to transcript the plugs heterogeneit...
#1Ali Tarokh(UIUC: University of Illinois at Urbana–Champaign)H-Index: 8
#2Roman Y. Makhnenko(UIUC: University of Illinois at Urbana–Champaign)H-Index: 12
Last. Dustin E. Sweet(TTU: Texas Tech University)H-Index: 11
view all 7 authors...
Abstract Subsurface reservoirs are targeted formations for geologic carbon dioxide (CO2) storage. Even if proper management of injection pressures minimizes the risks of induced seismicity, high pressure CO2 can interact with brine-saturated host rock and cause microstructural changes that lead to alterations in poromechanical properties of the rock. The effect is well pronounced in carbonate-rich rock, but observations on silica-rich reservoirs are ambiguous. In this study, we report a broad ra...
