Spatial variability in topology, connectivity and permeability of deformation band networks: Insights from the Jurassic Entrada Sandstone, Utah

Abstract

Networks of deformation bands have the potential to act as baffles to fluid flow, yet little work has been devoted to addressing their network properties, such as topology and connectivity. Motivated by this, we investigate the two-dimensional spatial variability of areal intensity, node and branch topology, and network connectivity within select deformation band networks in the Jurassic Entrada Sandstone (Utah). The results highlight distinct topological signatures for deformation band networks, dominated by Y-nodes, and IC- and CC-branches. Low proportion of isolated II-branches reflects the evolution of deformation bands through bifurcation and abutment (Y-nodes) to form interconnected networks. A key observation is that network connectivity and topology exhibit great spatial variability within one and the same deformation band network. We evaluate effective permeabilities across the deformation band network, incorporating a topological measure of network connectivity into the permeability calculations. Results highlight that deformation band networks with >1.5 connections per branch can significantly reduce effective permeabilities, whereas networks with low connectivity may offer pathways for tortuous fluid flow.