Articles | Volume 14, issue 3
© Author(s) 2023. This work is distributed underthe Creative Commons Attribution 4.0 License.
Transport mechanisms of hydrothermal convection in faulted tight sandstones
- Final revised paper (published on 10 Mar 2023)
- Supplement to the final revised paper
- Preprint (discussion started on 24 Nov 2022)
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor |
: Report abuse
RC1: 'Comment on egusphere-2022-1185', Anonymous Referee #1, 17 Dec 2022
- AC1: 'Reply on RC1', Guoqiang Yan, 03 Feb 2023
RC2: 'Comment on egusphere-2022-1185', Laurent Guillou-Frottier, 21 Dec 2022
- AC2: 'Reply on RC2', Guoqiang Yan, 03 Feb 2023
Peer review completion
AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
AR by Guoqiang Yan on behalf of the Authors (04 Feb 2023) Author's response Author's tracked changes Manuscript
ED: Referee Nomination & Report Request started (11 Feb 2023) by Susanne Buiter
RR by Laurent Guillou-Frottier (13 Feb 2023)
ED: Publish subject to technical corrections (20 Feb 2023) by Susanne Buiter
ED: Publish subject to technical corrections (20 Feb 2023) by Susanne Buiter(Executive editor)
AR by Guoqiang Yan on behalf of the Authors (21 Feb 2023) Manuscript
The authors perform numerical simulation of a geothermal system and the interaction between a deep fault, lateral faults with a sandstone reservoir. The study aims to explain high observed temperatures in the Piesberg quarry, Germany using a sensitivity analysis around the fault and reservoir properties. My comments are mainly about clarification and publication is recommended after a minor revision.
Eq 1: Can you explain what Sm is? I assume it should be based on porosity, fluid density and their compressibilities and that you then can go from a time derivative of mass to a time derivative of pressure. However, is Sm then pressure dependent or assumed constant? Some definitions and assumptions should be given. You also seem to assume single phase.
What is the index m in qm?
Eq3 Does ‘effective’ also include the fluid?
The density should vary with temperature. Can you comment on how that was modeled?
175 Can the authors give the definition of Rayleigh number and its importance. What determines its value?
Table 1: Please add mathematical symbols for identification with the model parameters.
188 The kappa values have not been defined as far as I can see. What do they represent? What are the indexes MF and SST? If they correspond to values in table 1, the abbreviations should be listed there as well.
205 What is meant by ‘initial temperature’ in this case? Do you mean based on boundary conditions before flow is accounted for or simply an assumed geothermal gradient? Rather than ‘initial temperature’, do you not really mean ‘initial guess’ since you are only interested in the dynamic steady state? A thermal anomaly sounds to me a difference from an expected trend if the circumstances were as everywhere else, e.g. no faults etc. Is that what you mean?
Can you define mathematically how you define the initial state based on your main equations?
224 A mathematical definition of Pe number should be given earlier so it is clear how the parameters are combined.
In the figures showing temperature vs depth it would be good to include the observed anomaly of the Piesberg quarry one wants to explain since the sensitivity analysis can indicate which parameter is more likely to explain it. For example, figure 7 shows that a high fault permeability is needed to explain a high temperature. Is it within range? Alternatively you could discuss how your model explains the observations more quantitatively in 4.2. Can you state something certain about what is needed for such explanation? If the fault is needed, what properties must it at least have to realistically explain the observations? Which mechanisms or parameters are less important?