Carbon dioxide (CO2) capture and storage (CCS) is considered widely as one of promising options for CO2 emissions reduction, especially for those countries with coal-dominant energy mix like China. Injecting and storing a huge volume of CO2 in deep formations are likely to cause a series of geomechanical issues, including ground surface uplift, damage of caprock integrity, and fault reactivation. The Shenhua CCS demonstration project in Ordos Basin, China, is the first and the largest full-chain saline aquifer storage project of CO2 in Asia. The injection started in 2010 and ended in 2015, during which totally 0.3 million tonnes (Mt) CO2 was injected. The project is unique in which CO2 was injected into 18 sandstone formations simultaneously and the overlying coal seams will be mined after the injection stopped in 2015. Hence, intense geomechanical studies and monitoring works have been conducted in recent years, including possible damage resulting from the temperature difference between injected CO2 and formations, injection induced stress and deformation change, potential failure mode and safety factor, interaction between coal mining and CO2 geological storage, determination of injection pressure limit, and surface monitoring by the interferometric synthetic aperture radar (InSAR) technology. In this paper, we first described the background and its geological conditions of the Shenhua CCS demonstration project. Then, we gave an introduction to the coupled thermo-hydro-mechano-chemical (THMC) processes in CO2 geological storage, and mapped the key geomechanical issues into the THMC processes accordingly. Next, we proposed a generalized geomechanical research flowchart for CO2 geological storage projects. After that, we addressed and discussed some typical geomechanical issues, including design of injection pressure limit, CO2 injection induced near-field damage, and interaction between CO2 geological storage and coal mining, in the Shenhua CCS demonstration project. Finally, we concluded some insights to this CCS project.

https://cyberleninka.org/article/n/676280.pdf

The geomechanics of Shenhua carbon dioxide capture and storage (CCS) demonstration project in Ordos Basin, China

Leakage risk assessment of a CO2 storage site: A review

Integrity analysis of CO2 storage sites concerning geochemical-geomechanical interactions in saline aquifers

CO 2 geo‐sequestration into saline aquifers and an enhanced geothermal system (EGS) are two of the most effective solutions to reduce CO 2 emissions into the atmosphere. The significance of thermal‐hydrological‐mechanical‐chemical (THMC) interactions is well identified in these two processes: fluid and heat flow, solute transport within a three‐phase mixture; stresses and displacements related to geomechanical effects; non‐isothermal effects on fluid properties and reaction processes; and equilibrium and kinetics of fluid‐rock and gas‐rock chemical interactions. In this paper, a novel numerical model is developed to describe the THMC processes mathematically. One mean stress formulation, which is simplified from the geomechanical equations with full stress tensor, is employed to solve mean stresses and displacements. Chemical equilibrium and kinetics are considered to quantitatively simulate geochemical reaction associated with solute transport. A sequentially coupled computational framework is proposed and used to solve reactive transport of water, gas components, and chemical species in subsurface formation with geomechanics. It is designed to keep a generalized computational structure for different THMC processes. A practical case with complex chemical compositions is presented to analyze the THMC processes quantitatively on the coupled effects of geochemistry and geomechanics during CO 2 geo‐sequestration. In addition, a practical EGS case is presented to address the mutual effects of each THMC process quantitatively, especially the mutual effects of stress and chemical reaction. Heat transfer affects mean stress and geochemical reactions; mean stress impacts the solute transport and successive chemical reactions; and geochemical reactions are shown to have significant impact on the mean stress, pressure, or temperature.

A novel computational framework for thermal‐hydrological‐mechanical‐chemical processes of CO2 geological sequestration into a layered saline aquifer and a naturally fractured enhanced geothermal system

We straightforwardly synthesized nine different types of ruthenium nanoparticles by using a series of ruthenium metal precursors and ionic liquids. All the materials went for XRD, XPS and SAXS analysis, before going to CO2 hydrogenation reaction as catalyst. As per the results, it was clear that the coordination between anions of ionic liquids and ruthenium nanoparticles played an important role with respect to their catalytic performance in CO2 hydrogenation reaction. Surprisingly, less coordinated and large [DAMI][TfO] mediated ruthenium nanoparticles gave better results over other developed catalytic systems. Narrow size well distributed and stable insitu generated ruthenium nanoparticles were synthesized and found highly active in terms of formic acid formed during the CO2 hydrogenation reaction to other ionic liquid immobilized standing ruthenium nanoparticles. Low catalyst loading, ligand free approach, simple reaction protocol, easy product isolation steps and seven times catalyst recycling are major outcomes of this proposed work.

Ionic Liquid Mediated In Situ Synthesis of Ru Nanoparticles for CO2 Hydrogenation Reaction

https://researchrepository.wvu.edu/cgi/viewcontent.cgi?article=8397&context=etd

Influence of geochemical processes on the geomechanical response of the overburden due to CO2 storage in saline aquifers

This study investigates the hydro-mechanical aspects of carbon dioxide (CO2) injection into a depleted oil reservoir through the use of coupled multiphase fluid flow and geomechanical modeling. Both single-phase and multiphase fluid flow analyses coupled with geomechanics were carried out at the West Pearl Queen depleted oil reservoir site, and modeling results were compared with available measured data. The site geology and the material properties determined on the basis of available geophysical data were used in the analyses. Modeling results from the coupled multiphase fluid flow and geomechanical analyses show that computed fluid pressures match well with available measured data. The hydro-mechanical properties of the reservoir have a significant influence on computed fluid pressures and surface deformations. Hence, an accurate geologic characterization of the sequestration site and determination of engineering properties are important issues for the reliability of model predictions. The computed fluid pressure response is also significantly influenced by the relative permeability curves used in multiphase fluid flow models. While the multiphase fluid flow models provide more accurate fluid pressure response, single-phase fluid flow models can be used to obtain approximate solutions. The ground surface deformations obtained from single-phase fluid flow models coupled with geomechanics are slightly lower than those predicted by multiphase fluid flow models coupled with geomechanics. However, the advantage of a single-phase model is the simplicity. Limited field monitoring of subsurface fluid pressure and ground surface deformations during fluid injection can be used in calibrating coupled fluid flow and geomechanical models. The calibrated models can be used for investigating the performance of large-scale CO2 storage in depleted oil reservoirs.

https://researchrepository.wvu.edu/cgi/viewcontent.cgi?article=2499&context=faculty_publications

Sai B.K. Varre

Papers

Influence of geochemical processes on the geomechanical response of the overburden due to CO2 storage in saline aquifers

Geomechanical response of overburden caused by CO2 injection into a depleted oil reservoir