Project 1: Flow along a detachment fault

Project objectives

  • Explore hydrothermal flow along fault zones

  • Find which faults capture a rising plume and which do not

  • Understand how fault zone properties affect vent temperature

The first project builds upon lecture 3 on Structural controls on hydrothermal flow. We will explore under which conditions hydrothermal upflow can be “captured” by an inclined fault zone of enhanced permeability.

../../_images/andersen_fault_2017.png

Fig. 48 Figure taken from [Andersen et al., 2017] ; preferential fluid flow along a fault zone.

Deliverables

The goal of this project is to provide work on these topics

  1. Plume captureing, provide a sequence of 2D simulations that illustrate what can “happen” for different fault widths and fault permeabilities (check Fig. 29)

  2. Systematics, provide a “phase diagram” for fault width and fault permeability that illustrates the regime when the pume is captured by the fault zone.

  3. Vent temperature, provide information on the relationship between the fault’s ability to capture a plume and the resulting vent temperature.

The results should be delivered in a short powerpoint presentation.

Starting point

Case file

Download the basic case file from (Fault Flow Model).. It includes a basic setup for a fault-controlled hydrothermal system.

Meshing software

The example case uses a meshing software called Gmsh to create a mesh that resolves the fault zone. Gmsh is already installed within your docker containers, so there should be no need for installing additional software. The gmsh input file is in gmsh/make_mesh.geo.

../../_images/gmsh_screen.png

Fig. 49 Mesh created with gmsh.

Have a look at gmsh/make_mesh.geo and the Gmsh . Check that you (more or less) understand what’s happening and try to change things like fault width and and angle.

Post-processing

There are many ways of extracting information from a completed run. For this project, you will want to know how high the vent temperature is and where the venting occurs, so that you can evaluate if the plume was “captured” by the fault. You can either do this in paraview by using, for example, the “Plot Over Line” filter in Paraview. An alternative is to use the built-in postprocessing function of OpenFoam.

postProcess -func sampleDict -latestTime

It will read the system/sampleDict file (have a look!) and extract T along a line.

More powerful is, of course, to use python, like in Upflow temperatures in submarine hydrothermal systems.

Background reading