Modeling fracture porosity development using simple growth laws
Article first published online: 9 MAY 2005
Volume 43, Issue 3, pages 314–326, May 2005
How to Cite
Bloomfield, J. P., Barker, J. A. and Robinson, N. (2005), Modeling fracture porosity development using simple growth laws. Ground Water, 43: 314–326. doi: 10.1111/j.1745-6584.2005.0039.x
- Issue published online: 9 MAY 2005
- Article first published online: 9 MAY 2005
- Received February 21, 2003; accepted August 11, 2004.
A model of porosity development has been developed to investigate general relationships between simple fracture aperture growth laws and fracture porosity in evolved fracture arrays in aquifers. The growth of fracture apertures in two-dimensional orthogonal arrays with initially spatially uncorrelated lognormal aperture distributions has been studied, where aperture growth rate is proportional to an exponent of the flow rate through each fracture. The evolved arrays show geometrical phase changes as a function of the aperture growth rate exponent, e, and the standard deviation of the initial aperture distribution, σz. Low values of e and σz lead to bimodal aperture distributions, where apertures parallel to flow are preferentially enlarged. At moderate values of e and σz, there is a transition to a regime of more complex geometries consisting of networks of channel-like structures of preferentially enlarged apertures. At larger values of e, array-spanning channel-like paths of preferentially enlarged apertures develop, where the tortuosity of the channel-like paths is a linear function of σz. Following an initial growth phase, during which dynamically stable aperture configurations develop, arrays undergo simple amplification. The geometry of the evolved aperture fields is diverse and they can be highly complex; consequently, parameterization and prediction of their evolution in terms of the initial aperture distributions and growth rate laws is not trivial.