Geomechanical Feasibility Analysis of Salt Cavern Gas Storage Construction in Sanshui Basin, Guangdong Province

Round 1

Reviewer 1 Report (New Reviewer)

The reviewed paper “Geomechanical Feasibility Analysis Of Salt Cavern Gas Storage Construction In Sanshui Basin, Guangdong Province” consider results of experimental study of salt rock geomechanical properties. The laboratory experiments were conducted on the set of salt rock core samples under various stress conditions: tension, uniaxial compression, Brazilian test, triaxial compression test, test with heating, creep test. Based on obtained estimations of the salt rock properties, mechanical stability of the underground cavern in the considered region was evaluated. The results are of practical interest, and the main conclusion of the paper is that the salt formation in Sanshui Basin, Guangdong Province is suitable for the construction of underground salt cavern gas storage. 

I have some remarks, most of them are marked in the reviewed paper by yellow.

1.     P.5, “Core photos show that the molecular crystal grains…” – I doubt that you can see any molecules on the photos.

2.     P.6, “… the peak strength of the rock generally increases with the increase of confining pressure, the peak strength of the core generally increases” – I do not understand, why do you repeat part of the sentence?

3.     P.6, “… the peak strength of salt rock does not increase by multiple, but grad-ually decreases, and the axial deformation when entering plastic yield is also increasing” – incomprehensive statement, it needs in rewording.

4.     Fig.4, fig.9-12 – I would like to suggest adding more explanations in the figure captions: what are the red ellipses, what is difference between Fig.10a and 10b, what is “fitting of salt rock samples” (I suppose, you mean “fitting of creep rate dependance on stress difference?), what is shown in the Fig.12 lower graph?

5.     P.9, “… the creep rate is exponentially related to the deviatoric stress, and is significantly affected by the deviatoric stress …” – the second statement is a consequence of the first statement, you needn’t to repeat.

6.     P.11 – “… and made a comparison with the triaxial creep data… ” – there is no subject in this part of the sentence, you need to reword it.

7.     P.12, “Cohesion is the mutual attraction between adjacent parts of the same material” – you need not to explain, what is “cohesion”.

8.     P.14, “the three-dimensional geostress of the salt rock strata in this area is equal” – it is equal to what? Do you mean “the three components of the stresses are equal to each other”, or “the stresses are isotropic”?

9.     P.14 – what is “Cpower model”?

10.  P.15 – “z=12,42m” – should it be z=1242m? The last sentence on the p.15 has no predicate.

11.  Fig.16-17 – what component of the deformation (or displacement) is shown? it is hard to see any differences between left and right graphs in the Fig.17. Both figures should be made more clear.

12.  PP.17-18 – “Volume convergence rate” – should it be in %/year?

13.  Fig.21 – the scales are incomprehensive.

14.  In all the paper you do not show any values of measurement errors, even when presenting average strength meaning. I suggest you to add measurement errors.

15.  I recommend through editing the text.

I support the paper publication after corrections.

Comments for author File: Comments.pdf

Author Response

Thank you for your precious time to review my manuscript. Please see the attachment about the revision.

Author Response File: Author Response.docx

Reviewer 2 Report (New Reviewer)

The paper is interesting however require minor correction.

Detailed comments were inserted in attached file.

Comments for author File: Comments.pdf

Author Response

Thank you for your precious time to review my manuscript. Please see the attachment about the revision.

Author Response File: Author Response.docx

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The manuscript concerns the geomechanical analysis of UGS in rock salt deposits. The authors have performed wide laboratory tests on the rock salt samples. Using obtained data they have performed fitting the laboratory data to the common known Norton creep law and conducted numerical analyses for single and two salt caverns. In my opinion, the article is prepared in a good way. Needs some additional information and corrections. The comments are:

1. Please complete the literature review with works from outside China. The issues related to the study of the salt rock mass, laboratory tests and modeling of salt caverns have been conducted for several, if not several dozen years. There is a lack of basic literature in this field, in particular, the German and Polish experience.

2. Change the diameter sign to the appropriate one "Ø"

3. Table 2 - please change FALSE to N/A

4. Figs 16, 17, 22 - please add figures in higher resolution

5. Change volume shrinkage to volume convergence term

6. Which numerical method has been used in a simulation?

7. Please state which constitutive model has been adopted in simulations

8. Please give the parameters of rock mass layers used in analyses

Author Response

Thank you for the valuable comments. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Good work

Author Response

Thank you for your precious time and hard work.

Reviewer 3 Report

This paper authored by Haitao Li et al. investigated the geomechanically feasibility of salt cavern gas storage construction in Sanshui basin, Guangdong province. The manuscript is well organized. There are just several points which should be considered in the revised version of the manuscript.

1.       This paper only introduces the research progress of salt cavern gas storage in China, and does not give the current research status in the world.

2.       Please provide the content of salt and mud in the salt rock samples.

3.       The words in Figure 16, 21 are not very clear to read. Please revise.

4.       How does cyclic loading affect the mechanical properties of the salt rock?

Author Response

Thank you very much for the valuable comments. Please see the attachment.

Author Response File: Author Response.docx

Reviewer 4 Report

This paper conducts experimental research on salt rock's mechanical properties in the main salt layer of the Sanshui Basin. The paper is, in general attractive, but it needs significant improvement before it can be recommended for publication. The following comments must be addressed in the next version of the paper.

(1) The English of this manuscript should be polished thoroughly. Some sentences are wordy and unreadable

(2) The abstract's content needs to be simplified, and pay more attention to the conclusion and outcome.

(3) In table 1, the numbering of salt rock is messy and should be clarified and rearranged.

(4) Please give the actual photo of the self-designed core direct tensile loading device in Fig. 2.

(5) Delete the column of Confining Pressure in Table 3.

(6) Please given more detail on why the yield failure of salt rock can be described by the Mohr Coulomb criterion, and the salt rock creep model of the salt mine is consistent with Norton's steady creep model.

(7) In Section 3.3, Stability Analysis, a numerical tool appears to be involved. If so, please elaborate on numerical modeling and parametric input.

Author Response

Thank you very much for the valuable comments. Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors responded adequately to the reviewers' comments. 

Reviewer 4 Report

The comments are well answered, so it is recommended to accepting in the present form.