Characterizing Volumetric Contraction Fracture Networks for Fluid Flow

Date of Award

5-2026

Degree Name

Doctor of Philosophy

Department

Geological and Environmental Sciences

First Advisor

Donald Reeves, Ph.D.

Second Advisor

Peter Voice, Ph.D.

Third Advisor

Lucas Goehring, Ph.D.

Keywords

Columnar basalt, fracture mechanics, mudcracks, patterned ground

Abstract

Volumetric contraction fracture networks (VCNs) commonly develop in nature as the volume of naturally occurring geologic materials change resulting in the formation of a series of infinitely repeating irregular polygons. Fluid interactions with VCN patterns in rock, mud and permafrost is relatively unknown when compared to other natural systems. To characterize the VCN networks for fluid flow, a thick film technique requiring mud to be partially saturated is developed to generate patterns with connected growth intervals. Networks created using this technique is compared to VCN propagation in columnar basalts highlighting the similarities in pattern evolution using newly developed perturbation factor and maturity index equations. Measurements of developed thick film VCN patterns show that individual fractures contain a concave profile, the bulk of apertures contain a normal distribution, the spatial distribution of hierarchal master joints and mega columns, and the mechanical controls on junction migration within the pattern. Observations on the compaction and behavior of individual growth intervals within the thick film pattern is used to break the pattern into three distinct layers: the contracted stable (fully fractured), contracted metastable (active fracturing), and uncontracted metastable layers (unfractured). VCN pattern forming materials are plotted on a contracted stable to uncontracted metastable ternary diagram to show the difference in the expression of fractures in unique materials. Fluid simulations with a lognormal distribution in fracture aperture and hierarchal mega column fractures show the impact of preferential flow paths on particle breakthroughs. Natural variation in hydraulic conductivity in VCN patterns is explained by networks with mapped mega column fractures containing average particle breakthrough times significantly faster than networks without mega columns.

Access Setting

Dissertation-Abstract Only

Restricted to Campus until

5-1-2028

This document is currently not available here.

Share

COinS