Chapter 4 - Scaling of 2-D Permeability Tensors

Abstract

This chapter discusses the development of several approaches to evaluate a representative elementary volume (REV) and to upscale two-dimensional permeability tensors for a fractured rock mass. The permeability tensor of a fractured rock mass is a key parameter in describing fluid flow and transport behavior through the fractured rock mass. The permeability tensor provides information on the direction and magnitude of the major and the minor components of subareas of the rock. The variances in local permeability of the subareas provide an estimate of the heterogeneity of permeability. The chapter evaluates the two-dimensional permeability tensor for a relatively large region using four different sized fracture patterns sampled from separate exposures. The upscaling is made on the basis of the flow rates through the subareas rather than the local geometry of the fracture networks. This approach is applicable where the aperture is variable—for example where stress affects the opening or closure of fractures.