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  3. Two PhD positions in understanding sandstone deformation (4 years)

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Two PhD positions in understanding sandstone deformation (4 years)

Utrecht University's Faculty of Geosciences is looking for two PhD positions in understanding sandstone deformation (4 years). Are you interested? Then please read the full profile and apply.

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Arbeidsvoorwaarden

Standplaats:
Domplein, Utrecht, Utrecht
Dienstverband:
Tijdelijk contract / Tijdelijke opdracht
Uren per week:
38 - 40 uur
Salarisindicatie:
€ 2325 - € 2972 per maand
Opleidingsniveau:
WO

Functieomschrijving

In the framework of the Dutch research programme DeepNL on understanding subsurface dynamics caused by human activities, the Department of Earth Sciences at Utrecht University invites applications from highly motivated individuals for two PhD positions within the project titled:

A multi-scale, multi-physics framework for modelling the geomechanical response of sandstone reservoirs to pore fluid extraction

Extraction of fluids, like natural gas, from the Earth’s crust frequently results in surface subsidence and tremors, such as observed at the Dutch Groningen Gas Field. However, the long-term surface impact of fluid production cannot be predicted confidently. Within the above project, we will quantify the physical mechanisms causing long-term subsidence and seismicity. As deformation is driven by stresses transmitted across grain-to-grain contacts, microphysical models based on the processes operating at the grain-scale are needed. This project will identify and quantify the main grain-scale deformation mechanism(s) causing inelastic deformation of sandstone reservoir rocks, considering physical (e.g., microcracking, intergranular sliding) and chemical (e.g., stress-driven mineral dissolution) processes, to eventually enable prediction via computer modelling.

We will take a two-fold approach to determine the physical and chemical deformation processes operating at and near stressed grain-to-grain contacts: (1) from experiments conducted at in-situ reservoir conditions, and (2) from microstructures using state-of-the-art micro- and nano-analytical techniques.

The two available PhD positions concern:

PhD position 1 in Experimental Rock Mechanics

Supervisors: Dr S.J.T. Hangx, Dr H.E. King, Prof. Dr C.J. Spiers (promotor)

The aim of this 4-year PhD project is to experimentally determine the deformation processes operating in sandstone reservoir rock under realistic in-situ conditions. The approach will involve conventional mm-/cm-scale triaxial and uniaxial deformation experiments, potentially coupled to real-time X-ray computer tomography (4D-XCT), as well as μm-scale experiments to study the nano-scale evolution of grain contacts using high-resolution, surface microscopy (AFM) and chemical spectroscopy (Raman, NanoSIMS). The results will be used to develop quantitative, mechanism-based models describing the mechanical behaviour of the material.

PhD position 2 in Microstructural Analysis and Electron Microscopy

Supervisors: Dr O. Plümper, Prof. Dr M.R. Drury (promotor)

The aim of this 4-year PhD project is to look in detail at experimentally and naturally deformed sandstone, using state-of-the-art electron microscopy (EM) techniques including crystallographic orientation (EBSD) and spectroscopic (CL) mapping combined with 2- and 3-D structural and chemical imaging (FIB-SEM, TEM). Experimentally deformed samples will be compared to natural samples from a unique set of drill cores, already available at UU, spanning 50 years of depletion. The results will be directly relevant to the development of constitutive models, such as those developed in PhD position 1.


Throughout the project, there will be a close collaboration between both PhD candidates. The obtained results will be directly useable as a first step towards reservoir-scale upscaling of microphysical modelling, providing the much-needed physical basis to current field-scale models, which incorporate empirical laws. In a broader context, this project contributes directly to the transition from high-carbon fossil fuels, such as oil and coal, towards cleaner energy production using natural gas and geothermal energy extracted from sandstone reservoirs. Improved understanding of the processes controlling reservoir deformation, and accurately modelling this, is highly relevant to assessing and reducing risks of subsidence and seismicity associated with geo-energy production, as well as geological storage of CO2, natural gas, hydrogen fuel and compressed air energy.

More information about the DeepNL programme can be found online on the NWO DeepNL website.


Up to 10% of the candidates’ time will be dedicated to assisting in the BSc and MSc teaching programmes of the Earth Sciences Department.

Functie-eisen

  • Applicants must not have a PhD degree.
  • Applicants must hold a Master degree in Geosciences, Physics, or Materials Science, and must have good quantitative and programming skills as well as an interest in chemistry.
  • Applicants must have experience of Earth materials research, ideally in rock or materials mechanics or in rock physics.
  • Applicants must have excellent written and spoken English skills and be highly motivated to work in an international team.
  • Knowledge of high resolution analytical techniques is preferred.

Arbeidsvoorwaarden

The successful candidates will be offered a full-time position at first for one year. Depending on a good performance this may be extended to a total period of four years, with the specific intent that it results in a doctorate within this period. Employment conditions are based on the Collective Labour Agreement of the Dutch Universities. The gross monthly salary starts with €2,325 in the first year and increases to €2,972 in the fourth year of employment with a full-time appointment (salary level from 1 Feb. 2019). The salary is supplemented by a holiday allowance of 8% per year and an end-of-year bonus of 8.3%. In addition, we offer a pension scheme, collective insurance schemes and flexible employment conditions. For more information visit Working at Utrecht University.

In addition, we offer participation in the Dutch research programme DeepNL, funded by The Netherlands Organisation for Scientific Research (NWO), guaranteed funding for the research project and training activities, and a personalised training programme, mutually agreed upon recruitment, which will reflect the candidates' training needs and career objectives.

Additionele informatie

For additional information on Position 1 contact Dr S.J.T. Hangx: s.j.t.hangx@uu.nl.

For additional information on Position 2 contact Dr O. Plumper: o.plumper@uu.nl.