Evaluating the Influence of Wall-Roughness on Fracture Transmissivity with CT Scanning and Flow Simulations

D. Crandall — G. Bromhal — D. McIntyre

National Energy Technology Laboratory3610 Collins Ferry RoadMorgantown, WV 26507-0880USADustin.Crandall@pp.netl.doe.govGrant.Bromhal@netl.doe.govDustin.McIntyre@netl.doe.gov

ABSTRACT. Combining CT imaging of geomaterials with computational fluid dynamics provides substantial benefits to researchers. With simulations, geometric parameters can be varied in systematic ways that are not possible in the lab. This paper details the conversion of micro-CT images of a physical fracture in Berea sandstone to several tractable finite volume meshes. By computationally varying the level of detail captured from the scans we produced several realistic fracture geometries with different degrees of wall-roughness and various geometric properties. Simulations were performed and it was noted that increasing roughness increased the resistance to fluid flow. Also, as the distance between walls was increased, the mean aperture approached the effective aperture.

 

KEYWORDS: fracture flow, finite volume CFD, Navier-Stokes, permeability

1. Introduction

Fractures often provide primary flow pathways within low-permeability geological media. For decades researchers have examined the effects of fracture wall-roughness on fluid transport by separating fractures, measuring the fracture surfaces with a profilometer, reconstructing analogue geometric models, and ...

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