Permeability of tensile fractures in andesites

Abstract

Fractures play a fundamental role in the movement of fluids and the distribution of pore pressure within a reservoir. We present here laboratory permeability measurements for variably porous andesite samples before and after failure in tension. We find that tensile fractures increase sample permeability. Increases are large and small for samples with low and high initial permeabilities, respectively. We use these data to explore the scale dependence of the permeability of fractured andesite using a model that considers flow in parallel layers. The scale-dependence of the permeability of fractured rock is important to improve estimates of the equivalent permeability of geothermal systems. (The research reported here is published as Heap and Kennedy, 2016).