THMC4CCS

Overview

The United Nations Intergovernmental Panel on Climate Change (IPCC) provides several lines of ‎evidence that anthropogenic carbon dioxide (CO2) emissions into the atmosphere—reaching an all-time high record of 37 gigatonnes in 2023—are the primary driver of climate change, posing a serious threat to living systems‎‎. Mitigating climate change and its worst consequences requires rapid, deep and vast decarbonization to ‎achieve net-zero emissions by 2050. Energy systems models analysed by IPCC suggest that attaining ‎this goal is impossible without large-scale deployment of Carbon Capture and Storage (CCS) to ‎decarbonize hard-to-abate industries such as chemicals, cement, steel and fertilizer manufacturing. ‎Several billion tonnes (gigatonnes, Gts) of CO2 need to be annually captured from large industrial sources, ‎instead of being emitted into the atmosphere, and injected into deep sedimentary layers, particularly saline ‎aquifers due to their huge storage capacity, in the upcoming decades. Challenges associated with such ‎large-scale injections, which entail scaling up the current storage rate by factors as large as 200, must be comprehensively studied.

Challenges in front of CCS scaleup can only be addressed in light of the underlying coupled thermal-hydraulic-mechanical-chemical (THMC) processes. An important process is CO2 dissolution into the ‎resident pore fluid produces carbonic acid, which drives geochemical reactions, primarily in terms of mineral ‎dissolution and precipitation. Geochemical CO2 -brine-rock interactions may alter the rock’s pore structure and potentially, leading to ‎time-dependent alterations in its hydraulic (e.g., porosity, permeability and two-phase flow) and mechanical ‎‎(e.g., stiffness and strength) properties. As such, these interactions contribute to pressure and ‎stress redistribution in the subsurface and, thus, to unsolicited side effects of massive CO2 injection: (i) fault reactivation, which may compromise caprock integrity and increase the risk of CO2 leakage, (ii) perceivable induced seismicity, harming public perception of CCS, and (iii) ‎differential ground surface uplift, posing risks to infrastructure. Thus, our ability to forecast and quantify coupled THMC processes of CO2 injection is crucial for CCS deployment at scale in a timely and safe ‎way. ‎

THMC4CCS aims to develop an improved understanding of reactive flow and transport phenomena in the CCS context to reduce uncertainties around the subsurface response to CO2 injection and the long-term fate of the injected CO2. To achieve this goal, THMC4CCS defines two specific objectives: to (1) advance knowledge of pore-scale processes governing geochemical reactions of CO2 with sedimentary rocks and their impact on flow and mechanical rock properties and (2) develop and verify constitutive models of CO2-rock interactions for quantitative field-scale evaluations. To tackle these objectives, THMC4CCS integrates laboratory experiments—including flow-through experiments with cutting-edge pore-scale imaging techniques—and coupled multiphysics numerical simulations.

Fund details