Permeability prediction based on fractal pore‐space geometry

Abstract

Estimating permeability from grain‐size distributions or from well logs is attractive but difficult. In this paper we present a new, generally applicable, and relatively inexpensive approach which yields permeability information on the scale of core samples and boreholes. The approach is theoretically based on a fractal model for the internal structure of a porous medium. It yields a general and petrophysically justified relation linking porosity to permeability, which may be calculated either from porosity or from the pore‐radius distribution. This general relation can be tuned to the entire spectrum of sandstones, ranging from clean to shaly. The resulting expressions for the different rock types are calibrated to a comprehensive data set of petrophysical and petrographical rock properties measured on 640 sandstone core samples of the Rotliegend Series (Lower Permian) in northeastern Germany. With few modifications, this new straightforward and petrophysically motivated approach can also be applied to metamorphic and igneous rocks. Permeability calculated with this procedure from industry porosity logs compares very well with permeability measured on sedimentary and metamorphic rock samples.

Permanent carbon dioxide storage in deep-sea sediments

“…portant because minor increases in porosity have been shown to generate large increases in permeability (22)(23)(24). The exact relationship between porosity and permeability in carbonate sediment is highly variable (25), and further work is required to quantify whether carbonate dissolution will have a significant effect.…”

TOUGHREACT User's Guide: A Simulation Program for Non-isothermal Multiphase Reactive Geochemical Transport in Variably Saturated Geologic Media, V1.2.1

“…Laboratory experiments have shown that modest reductions in porosity from mineral precipitation can cause large reductions in permeability (Vaughan, 1987). Detailed analysis of a large set of field data also indicated a very strong dependence of permeability on small porosity changes (Pape et al, 1999). This is explained by the convergent-divergent nature of natural pore channels, where pore throats can become clogged by precipitation while disconnected void spaces remain in the pore bodies (Verma and Pruess, 1988).…”

Investigation of porosity and permeability effects from microstructure changes during limestone dissolution

“…The most commonly used models relating permeability to porosity in porous media are based on the original work of Carman [1937]. Permeability k and effective porosity f e (i.e., pore space that effectively contributes to fluid flow) are linked through a power-law relationship, k / f e n or, alternatively, a linear combination of power-laws k / P i a i f e n i [Pape et al, 1999]. Asymptotically, it can be considered that the exponent n varies continuously with the evolution of the porosity versus permeability, so that n is the slope of the tangent at any point of the log(k) versus log(f e ) curve.…”