Some observations on the scale dependence of permeability by pumping tests

Abstract

[1] The dependence of scale in estimates of permeability or transmissivity in pumping tests is addressed in terms of internal architecture. The need for using geologic models that go beyond treating heterogeneity as a multinormal logarithmic field is noted. By using stratification as a vehicle and simulating flow, the role of the internal architecture of the aquifer is demonstrated. Specifically, transient data generated with the help of a stratified model are evaluated without consideration of internal architecture or geological imprint, and the consequences on estimates of aquifer properties are examined particularly in terms of scale. Evidence of scale effects should suggest the need for evaluating pumping tests with models that incorporate geologic considerations.

Mineralization of carbon dioxide sequestered in volcanogenic sandstone reservoir rocks

“…Our models assume that injectivity is directly determined by the core-scale permeability, which may be an overly conservative assumption. In most cases, the effective permeability at the scale of injection (10's of meters) can be 1 or even 2 orders of magnitude higher than the core-scale permeability (Raghavan, 2006). This difference is usually attributed to larger scale heterogeneity, including the presence of fractures, and tends to be more significant in rocks with lower permeability.…”

Deriving Three‐Dimensional Properties of Fracture Networks From Two‐Dimensional Observations in Rocks Approaching Failure Under Triaxial Compression: Implications for Fluid Flow

“…These studies suggest that permeability increases with spatial scale. The presence of stratification, layering, and other heterogeneities with a spatial dimension larger than the typical core sample produces this spatial dependence (e.g., Raghavan, 2006). Laboratory data further support the idea that permeability increases with spatial scale (e.g., Schulze‐Makuch et al., 1999).…”

Impact of model complexity and multi-scale data integration on the estimation of hydrogeological parameters in a dual-porosity aquifer

“…Mansour et al, 2011;Raghavan, 2004;Schad and Teutsch, 1994;Thorbjarnarson et al, 1998). Pumping tests have been simulated with finite difference (Barrash and Dougherty, 1997;Cheng and Chen, 2007;Halford and Yobbi, 2006;Kaleris et al, 1995;Lee et al, 2007;Leven and Dietrich, 2006;Mohamed and Rushton, 2006;Raghavan, 2009Raghavan, , 2006Schroth and Narasimhan, 1997), finite elements, and hybrid finite elements -finite difference models (Chen and Jiao, 1999;Lebbe et al, 1992). Radial flow models based on cylindrical coordinate grids are particularly appropriate for the simulation of pumping tests since they provide a more precise representation of the flow field around the pumping borehole (e.g.…”