NERC Centre for Doctoral Training in Oil & Gas (2016 start)
Project Title: Deformation adjacent to mobile evaporite bodies – modelling approaches and outcrop
examples from the Alps.
Host institution: University of Aberdeen
Supervisor 1: Prof. Rob Butler
Supervisor 2: Dr Clare Bond, Supervisor 3: Dr Rod Graham
Project description:
Models of evaporite mobility are based on the key physical properties of halite: it is both significantly
weaker and less dense than almost all other sedimentary rocks found in basins. Substantial
analogue modelling campaigns have led to the modern paradigm that evaporite mobililty in
sedimentary basins is driven by “down-building”. Thus the sediment load acting on an evaporite layer
generates swells and these highs amplify by continued sedimentation in the adjacent lows – breaking
out into extrusive “glaciers” to form canopies. Although the down-building model has received
widespread application on many continental margins and sedimentary basins, orogenic belts also
contain significant volumes of evaporites which, if they became mobile during orogenesis, did so far
removed from any syn-kinematic sedimentation. Existing field descriptions from the Western Alps,
are not compatible with the down-building model. Evaporite bodies cross-cut thrust structures
indicating late-stage intrusion. If confirmed these relationships introduce significant complexity into
models of evaporite mobility in sedimentary basins and a concomitant increase in structural
uncertainty when evaluating both reservoir geometry and performance.
This project will use outcrops of evaporites entrained along faults and in cross-cutting bodies –
focusing on outcrops from the French Alps. Here Triassic-derived halite and gypsum forms zones,
up to several 10s metre wide along thrusts and later faults. Larger bodies contain rafts of countryrocks in various states of disaggregation. These sites will be mapped, tracking the distribution and
patterns of evaporite-lined subsidiary faults. The internal structure of evaporite layers analysed and
kinematic indicators used in selected transects to establish flow systems (Couette vs Poiseuille Flow)
and relate these in turn to the distribution of entrained wall-rock fragments. Outcrop locations will be
captured digitally – using LIDAR and photogrammetric techniques as appropriate. These 3d virtual
outcrops can then be used for synthetic seismic modeling, for comparison with subsurface examples.
The field relationships will then be used to test and challenge halokinetic models.
CDT Research theme(s): 1 Exploration in Challenging Environments 70%. 2. Mature Basins 30%.
Improved understanding of salt deformation and salt-associated plays.
Research context: Butler has extensive field experience in the Alps, running industry short courses
on continental margin and slope process using Alpine analogue, including salt. Bond has been
utilising virtual outcrop geology to capture structural field data. Bond has a current NERC CDT PhD
utilising virtual outcrop geology, and will join a growing team of PhD and PDRA’s with virtual outcrop
geology expertise including a dedicated RA. The department has a large cohort of HC focused PhD
students. Graham is a world expert on salt systems with active Alpine research.
Research costs: Field work (£15k). UoA will fund extra costs through training and consulting
income. UoA has relevant software licences, and kit – LiDAR/photogrammetry for virtual outcrop
geology.
Career routes: The student will be well placed for a career in research, exploration & production
geoscience, and specialist structural geology consultancy. This PhD provides training opportunities
in seismic interpretation and forward modeling, structural geology mapping and modeling together
with general skills in 3D visualization and interpretation, enhanced by modern digital mapping
technologies.
Submissions must conform to this single-sided A4 format. The Awards Committee reserves the right not to
consider submissions that do not adhere to this condition.