The aim of this project is to conduct a detailed, laboratory-based study investigating how grain-coating clays, crucial to sandstone reservoir quality, behave during sediment transport.
Detrital grain-coating clays which form on a sand grain before, during or immediately after deposition (Dowey et al., 2017), are often interpreted as pre-cursors for well-developed, diagenetic grain-coating clays. These are found in deeply buried petroleum reservoirs with anomalously high porosity and permeability (e.g. Aagaard et al., 2000; Ajdukiewicz and Larese, 2012; Dowey et al., 2012). Despite their key control on sandstone reservoir quality, little is known about the stability of these detrital grain-coating clays during sediment transport and how this affects their preservation potential.
This PhD project will build on preliminary work on grain-coat stability which concluded that sediment transport processes generally reduce the thickness and completeness of the detrital grain-coating clays; two key properties that determine the preservation potential of these early coatings.
During the project laboratory experiments will be conducted to simulate transport of coated grains, followed by the analysis of both the transport processes and the deposits. This project will establish the key controls on the stability of detrital grain-coating clays and the potential effects of these on the formation of diagenetic grain-coating clays at depth, and thus the overall reservoir quality potential of the deposits.
This PhD project will offer a quantitative investigation of the impact of sediment transport processes on detrital grain-coating clays and the effect on porosity and permeability in the deposit. The work will consist of detailed flume tank experiments that simulate open-channel and gravity flow conditions with sediment collected from modern estuaries, for example the Ravenglass Estuary in the Lake District (NW England; e.g. Wooldridge et al., 2017), using sampling locations that are known to have high concentrations of grain-coating clays. Subsequently the flow properties (e.g. velocity and turbulence; e.g. Baas et al., 2009) and sediment characteristics (e.g. sorting, composition, state of the grain coating, etc.) will be examined in detail.
During the project the candidate will work in a multidisciplinary team with members of staff from the sedimentary geology and petroleum geology research groups within the Department of Earth, Ocean and Ecological Sciences and collaborate with staff in the Hydraulics Laboratory, which is based in the School of Engineering. The PhD candidate will receive training in the design and running of flume experiments and the use of several analytical techniques including ultrasonic velocimetry (UDVP), standard petrography, and SEM. Additionally, the candidate will be trained in scientific writing and will publish results in international peer-reviewed journals. The project comprises both pure and applied aspects of (petroleum) geology and will therefore be suitable for candidates who wish to pursue a career in either academia or in industry.
To apply for this opportunity please visit: https://www.liverpool.ac.uk/study/postgraduate-research/how-to-apply/
and click the ‘Apply online’ button.
Full funding (fees, stipend, research support budget) is provided by the University of Liverpool for 3.5 years for UK or EU citizens. Formal training is offered through partnership between the Universities of Liverpool and Manchester. Our training programme will provide all PhD students with an opportunity to collaborate with an academic or non-academic partner and participate in placements.
Aagaard, P., Jahren, J.S., Harstad, A.O., Nilsen, O. & Ramm, M. 2000. Formation of grain-coating chlorite in sandstones. Laboratory synthesized vs natural occurrences. Clay Minerals, 35, 261-269.
Ajdukiewicz, J.M. & Larese, R.E. 2012. How clay grain coats inhibit quartz cement and preserve porosity in deeply buried sandstones: Observations and experiments. AAPG Bulletin, 96, 2091-2119
Baas, J.H., Best, J.L., Peakall, J. & Wang, M., 2009. A phase diagram for turbulent, transitional, and laminar clay suspension flows. J. Sediment. Res., 79, 162-183.
Dowey, P.J., Hodgson, D.M. & Worden R.H. 2012. Pre-requisites, processes, and prediction of chlorite grain coatings in petroleum reservoirs: A review of subsurface examples. Marine and Petroleum Geology. 32, 63-75.
Dowey, P.J., Worden, R. H., Utley, J. and Hodgson, D.M., 2017. Sedimentary controls on modern sand grain coat formation. Sedimentary Geology, 353, 46-
Wooldridge, L. J., Worden, R. H., Griffiths, J., & Utley, J. E., 2017. Clay-coated sand grains in petroleum reservoirs: understanding their distribution via a modern analogue. J. Sediment. Res., 87, 338-352