Fluid flow in faulted and fractured sandstone reservoirs and aquifers

Projects address the effect of faults and fracture systems on fluid migration in sandstone formations. We use field mapping of alteration patterns, petrography, and various analytical tools to infer conditions and directions of past fluid flow and the interaction of flow with structural features and regional tectonic events. The flow properties of structural features as inferred from the observed alteration patterns are then compared to measured petrophysical properties.
View over iron oxide alteration zones in Jurassic Aztec Sandstone at Valley of Fire, Nevada. Alteration reflects multiple stages of oxidation and reduction of the eolian sandstone by fluids migrating in response to tectonic processes and exhumation.
Sequence of alteration and fluid flow events in the Jurassic Aztec Sandstone at Valley of Fire, NV. The sandstone is stained red during or soon after deposition in a desert environment. Two later stages of groundwater flow result in yellow, orange, and purple alteration colors. These flow events are correlated with Late Cretaceous Sevier thrusting and Tertiary Basin and Range faulting.
Hematite staining of Aztec Sandstone reflects the ponding of ground water flow across deformation bands (arrows) that act as barriers to flow due to porosity and permeability reduction. Valley of Fire, NV. Quarter for scale.
Hematite alteration halos adjacent to joints result from preferred fluid flow along joints. In this example, joints have been sheared (half arrows) subsequent to the hematite precipitation thus offsetting the initially symmetric alteration halo. Valley of Fire, NV. Swiss army knife for scale.


Publications

Eichhubl, P., Davatzes, N. C., and Becker, S. P., 2009, Structural and Diagenetic Control of Fluid Migration and Cementation along the Moab Fault, Utah: AAPG Bulletin, vol. 93, no. 5, p. 653-681. [html abstract, pdf full text, cover]

Eichhubl, P., and Flodin, E., 2005, Brittle deformation, fluid flow, and diagenesis in sandstone at Valley of Fire State Park, Nevada. In: Pederson, J., and Dehler, C. M., eds., Interior Western United States: Geological Society of America Field Guide, vol. 6, p. 151-167. [pdf full text]

Eichhubl, P., Taylor, W. L., Pollard, D. D. and Aydin, A., 2004, Paleo-fluid flow and deformation in the Aztec Sandstone at the Valley of Fire, Nevada-Evidence for the coupling of hydrogeologic, diagenetic, and tectonic processes. Geological Society of America Bulletin, vol. 116, no. 9, p 1120-1136. [html abstract, pdf full text, cover]
last update: 2/27/11

© P. Eichhubl, 2011

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