Hakan Heggernes

Insights into deformation band networks: Spatial variability in topology, connectivity and permeability

Hakan Heggernes

I will give a talk on my first PhD-paper, which was recently published. In this paper we characterize networks of deformation bands from an amazing outcrop close to the San Rafael Swell in Southeastern Utah. Here we use topology to assess deformation band intensity, network connectivity and effective permeability of deformation band networks. We also explore the spatial variability of such networks, and how these properties might affect a subsurface reservoir. See you on Wednesday!

Paper 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.