Utrecht University, Department of Earth Sciences

Utrecht University’s Faculty of Geosciences studies the Earth: from the Earth's core to its surface, including man's spatial and material utilisation of the Earth - always with a focus on sustainability and innovation. With a population of 3,400 students (BSc and MSc) and 720 staff, the Faculty is a strong and challenging organisation. The Faculty is organised in four Departments: Earth Sciences, Physical Geography, Sustainable Development, and Human Geography & Spatial Planning.

The Department of Earth Sciences conducts teaching and research across the full range of the solid Earth and environmental Earth sciences, with activities in almost all areas of geology, geochemistry, geophysics, biogeology and hydrogeology. Our key research themes are Earth & Planetary Processes, Sustainable Use of the Subsurface, Planetary Health & Environment, and Climate & Life. The department hosts a highly international tenured staff. We house or have access to a wide variety of world-class laboratories, among which are UU’s Electron Microscopy Centre, the Geolab, and the Earth Simulation Lab. We also have excellent High- Performance Computing facilities and organise a warm welcome for every new member.

About Utrecht:

Utrecht is the fourth largest city in the Netherlands with a population of nearly 360,000 and forms a hub in the middle of the country. Its historical city centre and its modern central station can easily be reached from our campus in Utrecht Science Park by public transport or by a 15-minute bicycle ride. Utrecht boasts beautiful canals with extraordinary wharf cellars housing cafés and terraces by the water, as well as a broad variety of shops and boutiques.

Homepage: https://www.uu.nl/geo/aw/

In the energy transition many technologies rely on the injection and extraction of energy carriers, like geothermal heat, CO₂ and hydrogen. Repeated fluid pumping could lead to clogging of fluid pathways. Are you ready to dive into the how, using cutting-edge imaging techniques?

Then the Department of Earth Sciences is looking for you! We would welcome a highly motivated and ambitious applicant for a PhD position to contribute to our research theme Sustainable Use of the Subsurface.

Project description

Clogging in geological formations poses critical challenges for subsurface applications from geothermal energy to CO₂ and hydrogen storage. While individual clogging mechanisms have been studied extensively, the dynamic interplay between physical particle deposition, chemical precipitation, and deformation-induced particle remobilisation remains poorly understood. These processes vary fundamentally across rock types – from porous sedimentary to fractured crystalline systems, with volcanic and altered crystalline rocks presenting unique intermediate cases. Recent advances in operando micro-computed tomography (µCT) enable unprecedented real-time visualisation of these processes, yet systematic investigation across diverse rock types and integration with predictive models remains lacking.

In this PhD study, you will be performing experiments and numerical simulations to understand and predict the clogging evolution in a range of geological media by:

• Quantifying physical and chemical clogging dynamics across a spectrum of rock types (porous sedimentary, porous volcanic, altered crystalline, and fractured crystalline rocks) using 4D µCT imaging
• Establishing the role of deformation in particle remobilisation and preferential flow path creation that controls clogging patterns
• Developing predictive digital rock physics and permeability evolution models from µCT data using machine learning and computational tools (PuMA/CHFEM/MOOSE) validated against experimental observations
• Bridging scales from pore-level processes (µm) to sample-scale behaviour (cm) through integrated experimental-numerical approaches

To achieve this, you will be doing in-situ experiments using our state-of-the-art in-house Zeiss Versa 610 µCT-scanner equipped with custom flow-through cells to capture clogging evolution. In addition, we will apply for beamtime at a synchrotron facility across Europe for critical experiments requiring very high imaging rates or ultra-high resolution. These experiments will be coupled with large- and small-scale flow-through experiments, using capabilities available at the High Pressure and Temperature Laboratory (in collaboration with Dr Suzanne Hangx) and the Porous Media Lab (in collaboration with Dr Amir Raoof) at the Department of Earth Sciences, to examine particle mobilisation thresholds, and how stress-induced deformation remobilises particles, creates new flow pathways, and redistributes clogging zones. Your experimental data and observations will be used to upscale from pore-scale physics to continuum behaviour.

If you are thrilled to dive deep into the world of real-time imaging for sustainable energy solutions, this is a great opportunity for you! This position offers you the chance to explore your passion for understanding the impact of subsurface activities and boost your career with high-impact research in a field that is rapidly growing.

The main supervisor of the study is Dr Roberto Rizzo.

Training

A personalised training programme will be set up, reflecting your training needs and career objectives. About 20% of your time will be dedicated to this training component, which includes following courses/workshops as well as training on the job in assisting in the Bachelor’s and Master’s programmes of the department at Utrecht University. Through interactions with the various scientists and stakeholders, you will be exposed to potential career paths in both academia and industry, helping you guide your future.

Qualifications

The successful applicant will hold an MSc in Earth Sciences, Geology, Physics, or related field by the time the position starts. Non-Dutch MSc diploma’s may be subjected to specific approval by the Board for Conferral of Doctoral Degrees before the candidate can be accepted in the PhD programme.

Good quantitative skills and programming experience (Python/MATLAB/Julia) are essential. Ideally, you will have experience with acquisition and processing of tomographic images, rock mechanics, machine learning and/or numerical modelling.

Given the highly diverse nature of the research groups that you will be working with, excellent communication (written and spoken English) and interpersonal skills are essential. In return, you will be part of an international team in an inspiring environment.

If you already have a PhD degree, then we unfortunately cannot consider you for this position.

Do you feel that you are a good match for the position but feel you do not meet all of our requirements, or have questions regarding the skills you may need? Then get in touch with us, so we can explore how you potentially can learn and grow in this position.

Terms of employment

You will be offered a full-time PhD position, initially for one year with extension to four years in total upon a successful assessment in the first year, and with the specific intent that it results in a doctorate within this period. The gross monthly salary starts with € 3,059 in the first year and increases to € 3,881 in the fourth year of employment with a full-time appointment. Salaries are supplemented with a holiday bonus of 8% and an end-of-year bonus of 8,3% per year. A pension scheme, partially paid parental leave, and flexible employment conditions are based on the Collective Labour Agreement of Dutch Universities.

In addition to the collective employment conditions, Utrecht University has a number of its own arrangements. These include agreements on professional development, leave arrangements, sports and cultural schemes, and you get discounts on software and other IT products. We also give you the opportunity to expand your terms of employment through the Employment Conditions Selection Model. This is how we encourage you to grow. For more information, please visit working at Utrecht University.

For informal questions (not for applications), please contact Dr Roberto Rizzo via r.e.rizzo@uu.nl, or Dr Suzanne Hangx via S.J.T.Hangx@uu.nl.

To apply, please use this link to go to the advertisement on UU’s own website and follow the guidelines mentioned there. We aim for a quick selection procedure after the deadline of December 14^th, 2025. The position is already available from February 1^st, 2026, or preferably filled as soon as possible thereafter.

Note that international candidates that need a visa/work permit for the Netherlands require at least four months processing time after selection and acceptance. This will be arranged with help of the International Service Desk (ISD) of our university. Finding appropriate housing in or near Utrecht is your own responsibility and, unfortunately, we must warn that it is a tight market at the moment. In case of general questions about working and living in The Netherlands, please consult the Dutch Mobility Portal.

Online screening may be part of the selection. Commercial response to this ad is not appreciated.