An investigation of porosity-velocity relationships in faulted carbonates using outcrop analogues

Porosity and permeability are notoriously difficult to predict in carbonates, especially prior to drilling when there is a lack of direct petrophysical data. The aim of this paper is to document the initial results of an integrated outcrop and laboratory study designed to investigate the relationshi...

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Main Authors: Healy, D., Neilson, J., Haines, T., Michie, E., Timms, Nicholas Eric, Wilson, M.
Format: Journal Article
Published: Geological Society of London 2015
Online Access:http://hdl.handle.net/20.500.11937/43850
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author Healy, D.
Neilson, J.
Haines, T.
Michie, E.
Timms, Nicholas Eric
Wilson, M.
author_facet Healy, D.
Neilson, J.
Haines, T.
Michie, E.
Timms, Nicholas Eric
Wilson, M.
author_sort Healy, D.
building Curtin Institutional Repository
collection Online Access
description Porosity and permeability are notoriously difficult to predict in carbonates, especially prior to drilling when there is a lack of direct petrophysical data. The aim of this paper is to document the initial results of an integrated outcrop and laboratory study designed to investigate the relationships between pore systems and acoustic velocities in faulted Oligo-Miocene carbonates on the Mediterranean islands of Malta and Gozo. Depositional facies is shown to have a significant effect, with velocities in grain-dominated carbonates up to 1000 m s−1 higher than those in micrite-dominated carbonates. Based on outcrop structural data, the fault zones can be separated into three architectural components: a fault core; an intensely damaged zone; and a weakly damaged zone, with the last passing into undamaged protolith. Our data suggest that only the fault core component can be identified using porosity–velocity data, with P-wave velocity (Vp) values of 5000–6500 m s−1 at helium porosities of less than 5%. Our study is novel in that the prediction of elastic properties and acoustic velocities across fault zones is anticipated by linking laboratory-scale measurements with seismic-scale predictions through quantitative rock physics modelling.
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spelling curtin-20.500.11937-438502017-09-13T13:42:26Z An investigation of porosity-velocity relationships in faulted carbonates using outcrop analogues Healy, D. Neilson, J. Haines, T. Michie, E. Timms, Nicholas Eric Wilson, M. Porosity and permeability are notoriously difficult to predict in carbonates, especially prior to drilling when there is a lack of direct petrophysical data. The aim of this paper is to document the initial results of an integrated outcrop and laboratory study designed to investigate the relationships between pore systems and acoustic velocities in faulted Oligo-Miocene carbonates on the Mediterranean islands of Malta and Gozo. Depositional facies is shown to have a significant effect, with velocities in grain-dominated carbonates up to 1000 m s−1 higher than those in micrite-dominated carbonates. Based on outcrop structural data, the fault zones can be separated into three architectural components: a fault core; an intensely damaged zone; and a weakly damaged zone, with the last passing into undamaged protolith. Our data suggest that only the fault core component can be identified using porosity–velocity data, with P-wave velocity (Vp) values of 5000–6500 m s−1 at helium porosities of less than 5%. Our study is novel in that the prediction of elastic properties and acoustic velocities across fault zones is anticipated by linking laboratory-scale measurements with seismic-scale predictions through quantitative rock physics modelling. 2015 Journal Article http://hdl.handle.net/20.500.11937/43850 10.1144/SP406.13 Geological Society of London restricted
spellingShingle Healy, D.
Neilson, J.
Haines, T.
Michie, E.
Timms, Nicholas Eric
Wilson, M.
An investigation of porosity-velocity relationships in faulted carbonates using outcrop analogues
title An investigation of porosity-velocity relationships in faulted carbonates using outcrop analogues
title_full An investigation of porosity-velocity relationships in faulted carbonates using outcrop analogues
title_fullStr An investigation of porosity-velocity relationships in faulted carbonates using outcrop analogues
title_full_unstemmed An investigation of porosity-velocity relationships in faulted carbonates using outcrop analogues
title_short An investigation of porosity-velocity relationships in faulted carbonates using outcrop analogues
title_sort investigation of porosity-velocity relationships in faulted carbonates using outcrop analogues
url http://hdl.handle.net/20.500.11937/43850