Geological Storage of CO2: Mathematical Modeling and Risk Assessment (MatMoRA-II)

The primary goal of the project is to develop methods for modeling and simulating the pertinent flow dynamics of CO2 in appropriate storage sites. The project has achieved substantial results and achieved this goal, focusing on the five subareas: (i) thermal and mechanical effects, (ii) CO2 dissolution, (iii) caprock topography, (iv) optimized injection strategies, and (v) coupled flow-geomechanical models. The key results involve fully developed modeling capabilities at both the large and small scales in the caprock and dissolution subareas, as well as preliminary work in thermal and mechanical modeling and optimization. The project has examined important issues related to the role of heterogeneity and physical complexity to enhance or hinder the ability of convection-driven dissolution and structural features of the caprock to trap and secure CO2 over the long term. Additionally, continuous improvements to existing open-source software are part of ongoing work that will eventually lead to new, sophisticated optimization methods for engineering safe and cost-effective CO2 storage projects. The key deliverables have been publications in high-level peer-reviewed journals. Additionally, new research codes have been developed and shared among the project partners. In particular, in collaboration with the spin-off project "Numerical CO2 laboratory", we have developed a CO2-module in the open-source software MRST , which offers a comprehensive set of tools for modeling structural/stratigraphic, residual and solubility trapping. The module supports industry-standard input formats and offers a wide range of methods, ranging from simple structural analysis (spill-point and percolation type models), via vertical equilibrium methods, to fully implicit methods in 3D. In addition, the module offers a number of tutorial examples as well as simple access to public data sets used for benchmarking, including the Johansen field, Layer 9 from Sleipner, as well as regional data sets from the recent North Sea Storage Atlas. The MatMoRA II project has provided extensive knowledge and novel research results motivated by the injection of CO2 in saline aquifers. Much of the basic research that is conducted also have other applications, particularly for enhanced oil and gas recovery using CO2, but also for unconventional reservoirs, where understanding thermal and mechanical effects on different scales become increasingly important. As part of the MatMoRA II project, a comprehensive review of the state of the art of modeling of CO2 storage has been prepared for the 50th anniversary issue of the journal Water Resources Research.

In the proposed project, we will address important research questions regarding capacity estimates and long-term safety and risk factors related to geological storage of CO2. Simulation technology plays an important role in pushing these knowledge fronti ers, and therefore our goal is to advance the state-of-the-art in numerical simulation of subsurface storage. These efforts need to follow several parallel paths: (1) fast and reliable numerical methods for fundamental flow physics; (2) trustworthy frame works for software implementation; and (3) computationally efficient generalizations to account for couplings inherent in complex case-dependent physics such as thermal and geomechanical models. Our proposal consists of several research tasks that togeth er will generate efficient reduced models to handle more complex and realistic physics and coupled phenomena, a task that will be coordinated with concerted efforts to develop efficient software implementations. Using these new models, we intend to study the thermal and mechanical effects of CO2 injection, dissolution and flow in low-permeability structures, and the effect of caprock topography and integrity on CO2 migration. The key benefit of this project is the development of cutting-edge modeling tool s that can be used for extensive risk assessment studies that will improve our understanding of potential CO2 storage sites in Norway.