An investigation of porosity–velocity relationships in faulted carbonates using outcrop analogues
Published:January 01, 2015
David Healy, Joyce E. Neilson, Thomas J. Haines, Emma A. H. Michie, Nicholas E. Timms, Moyra E. J. Wilson, 2015. "An investigation of porosity–velocity relationships in faulted carbonates using outcrop analogues", Fundamental Controls on Fluid Flow in Carbonates: Current Workflows to Emerging Technologies, S. M. Agar, S. Geiger
Download citation file:
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.
Figures & Tables
Fundamental Controls on Fluid Flow in Carbonates: Current Workflows to Emerging Technologies
This volume highlights key challenges for fluid-flow prediction in carbonate reservoirs, the approaches currently employed to address these challenges and developments in fundamental science and technology. The papers span methods and case studies that highlight workflows and emerging technologies in the fields of geology, geophysics, petrophysics, reservoir modelling and computer science. Topics include: detailed pore-scale studies that explore fundamental processes and applications of imaging and flow modelling at the pore scale; case studies of diagenetic processes with complementary perspectives from reactive transport modelling; novel methods for rock typing; petrophysical studies that investigate the impact of diagenesis and fault-rock properties on acoustic signatures; mechanical modelling and seismic imaging of faults in carbonate rocks; modelling geological influences on seismic anisotropy; novel approaches to geological modelling; methods to represent key geological details in reservoir simulations and advances in computer visualization, analytics and interactions for geoscience and engineering.