Geostatistical, type-curve, and inverse analyses of pneumatic injection tests in unsaturated fractured tuffs at the apache leap research site near superior, Arizona

Guoliang Chen, Walter A. Illman, Dick L. Thompson, Velimir V. Vesselinov, Shlomo P. Neuman

Research output: Chapter in Book/Report/Conference proceedingChapter

23 Scopus citations

Abstract

Over 270 single-hole [Guzman et al., 1996] and 44 cross-hole pneumatic injection tests [Illman et al., 1998; Illman, 1999] have been conducted at the Apache Leap Research Site (ALRS) near Superior, Arizona. In this paper, we describe a geostatistical analysis of the single-hole data and type-curve as well as numerical inverse interpretations of one cross-hole test, PP4. Our geostatistical analysis yields information about the spatial structure of air permeabilities measured on a nominal scale of 1 m, as well as of other variables such as fracture density. Our type-curve and inverse interpretations of cross-hole test PP4 yield information about pneumatic connections, directional air permeabilities, and airfilled porosities on scales ranging from a few meters to a few tens of meters. The numerical model can be applied simultaneously to pressure data from multiple borehole intervals (and multiple cross-hole tests), which amounts to "pneumatic tomography" of the rock. Our analyses suggest that (a) pneumatic pressure behavior of unsaturated fractured tuffs at the ALRS can be interpreted by treating the rock as a continuum on scales ranging from meters to tens of meters; (b) this continuum is representative primarily of interconnected fractures; (c) its pneumatic properties nevertheless correlate poorly with fracture density; and (d) air permeability exhibits multiscale random variations in space.

Original languageEnglish (US)
Title of host publicationDynamics of Fluids in Fractured Rock, 2000
EditorsPaul A. Witherspoon, Boris Faybishenko, Sally M. Benson
PublisherBlackwell Publishing Ltd
Pages73-98
Number of pages26
ISBN (Electronic)9781118669662
ISBN (Print)9780875909806
DOIs
StatePublished - 2000

Publication series

NameGeophysical Monograph Series
Volume122
ISSN (Print)0065-8448
ISSN (Electronic)2328-8779

ASJC Scopus subject areas

  • Geophysics

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    Chen, G., Illman, W. A., Thompson, D. L., Vesselinov, V. V., & Neuman, S. P. (2000). Geostatistical, type-curve, and inverse analyses of pneumatic injection tests in unsaturated fractured tuffs at the apache leap research site near superior, Arizona. In P. A. Witherspoon, B. Faybishenko, & S. M. Benson (Eds.), Dynamics of Fluids in Fractured Rock, 2000 (pp. 73-98). (Geophysical Monograph Series; Vol. 122). Blackwell Publishing Ltd. https://doi.org/10.1029/GM122p0073