Current PhD Students

Fluid - rock interactions are responsible for many chemical changes within groundwater and geothermal systems. Through these reactions the groundwater acquires its characteristic chemistry and the geothermal reservoir behavior changes. My project aims to define the mechanisms and conditions under which the trace elements are released from rocks into fluids during fluid - rock and fluid - mineral interactions.

The efficient recovery of methane from shale and coal requires rapid desorption and transport of the gas through the heterogeneous pore network at multiple length-scales (typically nano to micro). CO2 is commonly introduced to further stimulate methane production. Therefore, the pore network can often be subject to alteration, for example being partially blocked by mineral precipitates that are later dissolved by acidized fluids, or constriction caused by swelling of the material. These complex issues are of particular relevance for safe extraction of coal bed methane and shale gas, as well as for permanent sequestration of anthropogenic CO2.  This project will involve both experimental and theoretical study of gas diffusion and sorption kinetics at elevated temperatures and pressures representative of deep underground conditions. Samples will be evaluated before and after treatment by acidized fluids. Molecular dynamics simulations will be performed to determine the physical correlation between altered pore space and gas diffusion properties.  

Broadly, my research will involve: looking at vapour adsorption properties of geothermal reservoir rocks. Geochemical analysis of the effects of carbon dioxide and hydrogen sulphide injection into the subsurface. Obtaining mineral dissolution data to contribute towards producing models for the behaviour of a geothermal resource.

The focus of this study is to understand the effect of sedimentary and mechanical heterogeneities on pore scale flow within an aeolian sandstone petroleum reservoir. Sedimentary and mechanical heterogeneities may result in baffles, barriers and even redirection of fluid flow. Additionally, they may also lead to the creation, destruction or limitation of critical flow pathways. Further understanding of the relationship between heterogeneities and pore scale flow could lead to increased productivity and longevity of petroleum reservoirs. In this study, the Anisian aeolian facies of the Helsby Sandstone Formation will be studied, which acts as a producing reservoir in the East Irish Sea Basin and in the North Sea Oilfields.

In recent decades, the oil industry has contributed significantly to land cover change within the Niger Delta region of Nigeria. However, the true extent and severity of the land cover change due to oil production and exploration activities remains unclear. Therefore, the aims of this project are:

• To detect and model the magnitude, nature, direction and the likelihood of land cover changes in the Niger Delta.
• To determine and model the relationship between oil activities and the land cover changes.
• To model the proportional change in land cover due to variation in the amount of oil extraction

 

Geological storage of gas is not only an effective means to mitigate CO₂ emissions by injecting CO₂ underground, but also an excellent way to accommodate fluctuations in energy peak demands by storage of CH₄ and H₂. The main aim of this project is to analyse the impurity content in salt rock formations, used for underground gas storage, and its influence on rheological behaviour and deformation to improve the stability of salt caverns. The research involve geomechanical tests by using rock salt from salt mines and synthetic samples.

Downhole gasification offers a potential way to utilise difficult-to-extract and exhausted reservoirs in the North Sea by in-situ generation of hydrogen (and carbon oxides as displacement gas), which can then also be stored in the reservoir until needed. Seal rock, also called cap rock, is a crucial and sometimes overlooked factor in the evaluation of a potential hydrocarbon accumulation, and is critical in downhole gasification and storage of hydrogen.  In this project, we propose to develop a novel combination of complementary and multi-scale characterisation methods to enable a more accurate study of cap-rock cores, and provide the information needed for secure decisions regarding gas production and storage. We propose to use mercury porosimetry, together with mercury thermoporometry, gas sorption and computerised X-ray tomography (CXT) performed on post-porosimetry samples containing entrapped mercury, to characterise the pore structure of cap-rocks.

A number of studies have demonstrated that changing groundwater level is one of the key parameters that determines land motion above active and abandoned coal mines in the UK. New satellite Interferometric SAR (InSAR) techniques, such as the Intermittent SBAS, have been developed by the University of Nottingham to measure millimetre-scale changes over the land surface in rural and urban areas. The ISBAS algorithm has proved its capability in determining the link between land deformation and geology in multiple studies.
The principal aim of this project is to demonstrate the capability of the satellite InSAR, with the aid of ISBAS algorithm, in predicting the mine water levels in the areas of historical mining to create a simpler way of measuring ground water levels as an alternative to traditional techniques which can be expensive, invasive and labour intensive.

Publications:

Gee, D., Sowter, A., Novellino, A., Marsh, S., & Gluyas, J. (2016). Monitoring land motion due to natural gas extraction: Validation of the Intermittent SBAS (ISBAS) DInSAR algorithm over gas fields of North Holland, the Netherlands. Marine and Petroleum Geology, 77, 1338-1354.

Bateson, L., Gee, D., Sowter, A., Cigna, F., Novellino, A., Marsh, S, Broughton, P., & Satterley, C. (2017). Ground motion in areas of abandoned mining: A case study of the Intermittent SBAS (ISBAS) applied to the Northumberland and Durham coalfield. (Current Work)

This project will determine whether inherent heterogeneity is advantageous to engineering of sandstone reservoirs for carbon dioxide storage with a view to i) determining how natural reservoir heterogeneities offer advantages in terms of injection/ storage, and ii) to selectively divert or block CO2 transport within the reservoir system. It will involve modelling the effects on CO2 plume migration, at multiple length scales, of heterogeneities and how interventions such as polymer or water injection to block or divert flows, respectively.

Extraction of heavy oil is of increasing interest for the North Sea and worldwide. This project will aim to better understand relevant environmental science, and thereby improve the efficiency and assess the impact, of the THAI-CAPRI in-situ combustion-based, recovery process for heavy oil and bitumen deposits (such as the Athabasca tar-sands). Improving the efficiency of THAI requires greater understanding of various types of multi-phase flow, through the heavy oil deposits, and this work also provides parameters for reservoir-scale models. The project will use CFD, Lattice-Boltzmann and Monte-Carlo simulation methods to study flow problems, particularly migration of heavy oil mobilised by heat and/or combustion gases, and injection of nanoparticulate, downhole-upgrading catalysts in the gaseous oxidant. Very little information is currently available on these types of flows for geological porous media. Obtaining this information will improve design and operation of the recovery process. Work in collaboration with the University of Birmingham will focus on studies of pyrolysis and combustion reactions of heavy oil and bitumen within rock samples, including tar-sands and cracks within cap-rock cores (shales) to incorporate into modelling. Samples will be examined physically (e.g. XRay microtomography, TGA) and chemically (e.g. solvent extraction followed by HPLC) following reaction to determine distribution of coke and fracturing.

Random fields have been used by many researchers to model the spatial variation of the properties of heterogeneous materials such as soil, concrete and timber. The quality of the predictions made by these models depends on the accuracy of the statistical inferences made about the parameters of the underlying Gaussian random field of which the model is a transformation. Currently these parameters are directly inferred from experimental measurements of material properties using method of moment estimators. However measured properties are not point observations of the underlying random field but rather homogenisations of this field over some spatial domain and consequently direct statistical inference is suboptimal. This project develops a statistical methodology to indirectly infer the parameters of the underlying random field from its effective properties through approximate Bayesian computation since for most material properties the likelihood function is intractable.