Medici, G

Mountney, NP

Odling, NE

Ruelland, P

West, LJ

White Rose Research Online

This is a repository copy of Inferred Fluid Flow Behaviour in a fractured Red-bed aquifer: St Bees Sandstone Formation.White Rose Research Online URL for this paper:http://eprints.whiterose.ac.uk/92082/Version: Accepted VersionConference or Workshop Item:Medici, G, West, LJ, Mountney, NP et al. (2 more authors) (2015) Inferred Fluid Flow Behaviour in a fractured Red-bed aquifer: St Bees Sandstone Formation. In: 42nd IAH Congress: AQUA 2015, 13-18 Sep 2015, Rome (Italy). eprints@whiterose.ac.ukhttps://eprints.whiterose.ac.uk/Reuse Unless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version - refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher’s website. Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. Inferred fluid flow behaviour in a red-bed fractured aquifer: St Bees Sandstone Formation, UK Giacomo Medici1, L. Jared West1, Nigel P. Mountney1, Noelle E. Odling1, Philippe Ruelland2  1 School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds, W Yorkshire, LS2 9JT, UK 2  Total France EP, CSTJF, Av. Larribau, Pau, France  Corresponding author: Giacomo Medici, eegm@leeds.ac.uk  KEYWORDS: red-beds, channel sandstones, overbanks, silt drapes, faults, fractures  Understanding fluid-flow behaviour in arenaceous red-bed successions is globally important because such accumulations represent major aquifers for water supplies, geothermal energy and hydrocarbon reservoirs. The St Bees Sandstone Formation comprises Triassic fluvial red-beds and represents a case study to address this issue. This geological formation is part of the Sherwood Sandstone Group, which is the UK’s second most important aquifer. The formation is dominated by channelized fluvial architectural elements in which sandstones represent the most permeable lithology based on laboratory analyses (porosity 18 - 22%; Kh 800 - 4000 mD; Kv 150 - 700 mD). Mud-prone fluvial overbank architectural elements occur both at the base of channel belts and as interbedded bodies within channelized elements. Overbank elements are characterized by lower porosity and permeability values (porosity 14% - 18%; Kv 3 - 10 mD; Kh 50 - 400 mD) with respect to channelized elements, and therefore represent a key heterogeneity. Multi-level piezometer data indicate that the aquifer is horizontally layered whereas overbank elements enhance the aquifer’s layer-cake behaviour when they are interbedded in channelized elements. Another sedimentary heterogeneity is represented by white, in-channel silty sandstone drapes (porosity from 8% - 10%; permeability values of a few milliDarcies). Although matrix conduits facilitate fluid flow, tectonic features, which have been characterised through scanline surveys, also potentially represent significant fluid pathways. Vertical joints form strata-bound systems which terminate at bedding surfaces; bedding-parallel fractures establish communication between sub-vertical joints in adjacent units. Additionally, normal faults have extended damage zones with high fracturing density and high connectivity. The work conducted, that will be completed analysing pumping tests, has revealed how the St Bees Sandstone Formation potentially represents a heterogeneous dual-permeability aquifer.  

Inferred Fluid Flow Behaviour in a fractured Red-bed aquifer: St Bees Sandstone Formation

https://eprints.whiterose.ac.uk/92082/1/IAH%20Roma%20Medici%20et%20al%202015.pdf

Inferred Fluid Flow Behaviour in a fractured Red-bed aquifer: St Bees Sandstone Formation

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