I'm currently the lead-PI (unless indicated otherwise) on multiple research projects related to the long-term impact of gas production and salt cavern abandonment, long-term CO2 storage, temporary hydrogen storage and the long-term disposal of radioactive waste.
Current projects:
Hydrogen storage in Offshore Porous gEological formations in the Netherlands (HOPE) (2025-2029; co-PI)
Green hydrogen will play a pivotal role in future energy systems, requiring large-scale underground storage in porous geological formations. Depleted offshore and neighbouring onshore gas fields represent promising candidates for such storage in the Netherlands. Building upon extensive experience from geological carbon storage, this project aims to identify suitable storage sites and advance the understanding of large-scale hydrogen storage in subsurface formations. This project will investigate hydrogen flow and mixing dynamics, geochemical reactions, and geomechanical behaviour in fractured porous media. Particular emphasis will be placed on how the coupled interactions among these processes, together with cyclic hydrogen injection and withdrawal, influence caprock integrity, fault re-activation, and fluid-rock interactions. The outcomes will support the identification of optimal storage sites and the development of safe and efficient operational strategies for hydrogen storage in porous geological formations.
Long-term porosity-permeability evolution of backfilled openings in a radioactive waste repository: final healing behaviour of partially saturated granular backfill (2025-2026)
This project builds upon the outcomes of the PhD project described below, with a special focus on further improving our understanding of the microscale mechanisms of solution-precipitation transfer resulting in long-term healing and permeability reduction during late stage cavity closure.
Impact of cyclic pressure changes and H2 exposure on clay-rich caprock integrity (2024-2028; HyTROS GroenvermogenNL)
Safe and efficient underground hydrogen storage in porous reservoirs is partly determined by maintaining integrity of the sealing caprock formation. Thermo-hydro-chemo-mechanical changes in the caprock may lead to the creation of leakage pathways and/or movement along (pre-existing) fractures and faults. Many potential Dutch and European storage reservoirs are overlain by clay-rich formations. One of the key mechanisms that may occur within clay-rich caprock is the sorption of hydrogen to the clay-matrix. This sorption may lead to the development of swelling stresses and strains, which could impact potential leakage pathways in intact caprock or along pre-existing faults. In addition, direct pressure changes or thermal stresses could cause fault reactivation.
Numerical modelling of salt cavern abandonment or re-use for energy storage in single- and multi-cavern systems (2023-2027; collaboration with TNO; co-PI), and
Multi-scale validation of constitutive models for rock salt creep behavior and application to field-scale numerical models (2023-2027; collaboration with TNO; co-PI)
Salt caverns created for brine production or energy storage tend to converge due to salt creep, which may lead to induced seismicity surrounding the caverns and surface subsidence . However, the amount of cavern convergence and subsidence, particularly on the long-term, cannot be predicted with confidence, hindering the full assessment of surface effects. Within this programme, we will (1) quantify the physical mechanisms underpinning salt creep, with an emphasis on low stress creep behavior and dynamic recrystallisation, and (2) extending existing numerical modelling tools that by incorporating realistic grain-scale mechanisms, to accurately simulate salt creep and salt cavern deformation, as well as the associated surface impacts.
Re-use of depleted oil and gas fields for CO2 sequestration (2022-2026; ACT RETURN)
Globally, depleted oil and gas reservoirs represent huge potential storage volumes for CO2. However, Joule-Thomson cooling and freezing of any pore fluid, due to injection of high-pressure CO2 into a low-pressure, depleted reservoir, causes an important technical challenge. This could impact injectivity, but also near-well stability and well integrity. The current PhD position will focus on determining and quantifying the effects of re-pressurisation and pressure-temperature cycling on the mechanical and transport properties of sandstone reservoirs and clay-rich caprocks.
Impact of fluid extraction on the creep behaviour of clay-rich formations enveloping Rotliegend sandstone reservoirs (2021-2026; DeepNL)
Extraction of fluids, like natural gas, from the Earth’s crust frequently results in surface subsidence and tremors. This is largely caused by compaction of the gas reservoir. However, the rocks directly above and below the reservoir may also play a role. Many gas fields are surrounded by softer, clay-rich rock units that respond differently to gas production than the stiffer sandstone reservoir. We will identify and quantify the physical mechanisms causing slow deformation of these surrounding rock units, to improve and extend hazard predictions via computer modelling.
Concluded projects:
Evolution of the mechanical and transport properties of rock salt under simulated cavern wall conditions during cyclical hydrogen storage (2022-2025)
The integrity and efficiency of hydrogen storage in salt caverns, as an energy buffer, depends on the impact of hydrogen pressure cycling on creep and damage/permeability development in the cavern walls, i.e. on the magnitude and frequency of the injection-extraction cycle. Though it is recognised that salt creep and cavern wall porosity-permeability (i.e. damage) play an important role in determining cavern stability, storage integrity and operational safety, these phenomena are currently assumed to be unaffected by pressure cycling and neglected in models addressing cavern behaviour and H2-energy storage efficiency.
Long-term porosity-permeability evolution in and around backfilled openings in a radioactive waste repository in rocksalt (2021-2025)
The principal uncertainty regarding the containment capacity of a radioactive waste repository sited in rocksalt formations lies in predicting the long term convergent creep and sealing behaviour of backfilled shafts, galleries and boreholes created in the construction of the facility. Potential pathways for brine intrusion, expulsion and associated radionuclide release that must be considered in containment modelling include the backfilled openings themselves plus the surrounding permeable zone produced by excavation- and creep-induced microcracking, i.e. the excavation damage zone or EDZ. To model the closure evolution in the context of system performance, using finite element or other methods, constitutive equations describing the mechanical behavior and evolving transport properties of salt rock and of crushed salt backfill are essential. The present project consists of an experimental, microstructural and microphysical modelling study of the densification, healing and sealing behaviour of excavation-damaged rocksalt and of salt backfill under repository-relevant conditions, that will provide the basis for extrapolation of the rock salt behaviour in time.
A multi-scale, multi-physics framework for modelling the geomechanical response of sandstone reservoirs to pore fluid extraction (2019-2024; DeepNL)
Extraction of fluids, like natural gas, from the Earth’s crust frequently results in surface subsidence and tremors. The cause lies in reservoir compaction, driven by the increase in effective overburden stress due to decreasing reservoir fluid pressure. However, the long-term surface impact of fluid production cannot be predicted confidently. The key barrier to obtaining appropriate models is that the physical and chemical mechanisms responsible for reservoir compaction are poorly known and quantified at realistic subsurface pressure and temperature conditions. We will quantify these mechanisms causing long-term subsidence and seismicity, to enable prediction via computer modelling.