Page 280 - gas transport in porous media

277
Chapter 15: Air Permeability Measurements in Porous Media
still susceptible to measuring the subsurface characteristics of preferential flow paths
they are less likely to increase permeability by drying or other processes. Passive tests
are inexpensive to conduct using simple pressure transducers and electronic data log-
gers and the data are comparable to more conventional vadose zone pumping tests
(Rossabi and Falta, 2002). The information from these tests are generally specific to
the subsurface materials immediately adjacent to the individual test wells and may or
may not be accurately extended to the materials between test wells.
From the single well tests it is very difficult to uniquely quantify the heterogeneous
structure of the permeability field. Multi-well cross hole tests provide a solution
to this limitation. In these tests a series of boreholes are installed (orientation can
vary) sufficiently close together to assure communication between the wells. Using
multilevel packers, each of the boreholes is then segmented into a series of isolated
intervals. A pressure pulse (steady or decay) is then induced in one of the segments
while monitoring the response in all other segments. This process is repeated by
sequentially moving the source to each of the other individual segments. The three-
dimensional heterogeneous permeability field is then estimated through simultaneous
inversion of the pressure response data (Huang et al., 1999). This approach has been
termed pneumatic tomography (Vesselinov et al., 2001).

REFERENCES
Baehr,A.L., and M.F. Hult, Determination of the air-phase permeability tensor of an unsaturated zone at the
Bemidji, Minnesota Research Site, U.S. Geological Survey Program on Toxic Waste, Proceedings of the
Fourth Technical Meeting, Phoenix, Arizona, September 25–29, Water Resour. Invest. Rep., 88–4220,
55–62, 1988.
Baehr,A.L., and M.F. Hult, Evaluation of unsaturated zone air permeability through pneumatic tests, Water
Resour. Res., 27(10), 2605–2617, 1991.
Bear, J., Dynamics of Fluids in Porous Media, Dover Publications, Inc., New York, 1972.
Brace, W.F., J.B. Walsh, and W.T. Frangos, Permeability of granite under high pressure, J. Geophysical
Res., 73, 2225–2236, 1968.
Chandler, M.A., G. Kocurek, D.J. Goggin, and L.W. Lake, Effects of stratigraphic heterogeneity on
permeability in eolian sandstone sequence, Page Sandstone, Northern Arizona,AAPG Bull., 73(5), 658–
668, 1989.
Davis, J.M., R.C. Lohmann, F.M. Phillips, J.L. Wilson, and D.W. Love,Architecture of the Sierra Ladrones
Formation, Central New Mexico: Depositional controls on the permeability correlation structure, Geol.
Soc. Am. Bull., 105(8), 998–1007, 1993.
Davis, J.M., J.L. Wilson, and F.M. Phillips, A portable air-minipermeameter for rapid in-situ field
measurements, Ground Water, 32(2), 258–266, 1994.
Deutsch, C.V. and A.G. Journel, A.G, GSLIB: Geostatistical Software Library and User’s Guide, Oxford
University Press, New York, 1997.
Dreyer, T., A. Scheie, and O. Walderhaug, Minipermeameter-based study of permeability trends in channel
sand bodies, AAPG Bull., 74(4), 359–374, 1990.
Dykstra, H., and R.L. Parsons, The prediction of oil recovery by water flood, in Secondary Recovery of
Oil in the United States, 2nd ed., American Petroleum Institute, New York, pp. 160–174, 1950.
Eijpe, R., and K.J. Weber, Mini-permeameters for consolidated rock and unconsolidated sand, AAPG Bull.,
55(2), 307–309, 1971.
Falta, R. W. Analytical solutions for gas flow due to gas injection and extraction from horizontal wells,
Ground Water, 33(2), 235, 1995.