Cenozoic Subsidence History of the Northern South China Sea: Examples from the Qiongdongnan and Yinggehai Basins

Round 1

Reviewer 1 Report

The paper describes very clearly the geological processes that took place in The Qiongdongnan and Yinggehai Basins. The main problems of exploring the deeper layers of the described areas were shown and the relatively small amounts of data were used in a rational way.

The input data were correctly defined.

A very thorough analysis led to improved conclusions. Scientifically, I rate the work very well. 

The references in the publication are sufficient. The topic corresponds to the content of the publication.

The language of the publication is comprehensible.

I only found minor editing errors: 

in lines: 480, 546, 557, 576, 602 the value and the unit should be on one line

a single letter should not be left at the end of a line: line 605, 753.

With minor corrections, I recommend the article for publication in the journal Processes

Author Response

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Reviewer 2 Report

The United States Geological Survey estimates that the proven and unproven petroleum reserves in the South China Sea (SCS) are equivalent to 5 billion tons, with confirmed petroleum reserves amounting to no more than 1 billion tons. These estimates hold that 60% to 70% of the hydrocarbon in the South China Sea is natural gas (I have found two papers which supports the claim regarding the gas and petroleum reserves, see my remark no. 1). In the present study, the similarities and differences in the Cenozoic subsidence characteristics of the Qiongdongnan (QDNB) and Yinggehai (YGHB) basins have been investigated via comparative analysis, and then, the subsidence features of the two basins were compared with the geological processes that occurred in the south China sea and its adjacent areas to ascertain the main factors controlling the mechanisms of the subsidence in these two basins. The results of this study provide evidence for the reconstruction of the geodynamic processes. There are several issues which haven’t been described no considered in this paper. The authors should explain how did they calculate the porosity. The software/code applied in this research should be described. The results obtained in this work should be validated against previous publications dealing with this subject. It is recommended to reconsider this paper for publication, after performing the following major revisions.

Comments and Suggestions for Authors

1) (Introduction section –Lines no. 62 and 63) it is recommended to cite the following two papers and website:

[1] Liao, Fengrong, Xiaoqi Wu, and Shipeng Huang. “Geochemical Characteristics of Natural Gas in the Yinggehai-Qiongdongnan Basin, South China Sea.” Energy Exploration & Exploitation, 28, no. 1, 2010: 1–12. http://www.jstor.org/stable/26160783.

[2] Zhang, Y.; Zhang, L.; Mi, L.; Lu, X.; Wu, S.; Tang, L.; Zhou, J.; Xiong, X.; Zhu, J. Quantitative Analysis of Cenozoic Extension in the Qiongdongnan Basin, South China Sea: Insight on Tectonic Control for Hydrocarbon Reservoir Accumulation and Formation. Energies, 2022, 15, 4011. https://doi.org/10.3390/en15114011.

[3] Li Guoqiang, China Sea Oil and Gas Resources, China International Studies (CHS),

https://www.ciis.org.cn/english/COMMENTARIES/202007/t20200715_2762.html (accessed on 14/1/2023)

2) (Section 3.2 – Method and Parameters and section 3.2.2 – Parameters) the software/code applied in this research hasn’t been described. The authors should describe the calculation steps. Have the authors applied fractal calculation or Move software?

3) (Line no. 111) the seismic profiles of Qiongdongnan (QDNB) and Yinggehai (YGHB) basins should be cited

4) (Line no.194 – Table 1) how did the authors estimate or measured the porosity of the ground? It should be noted that the porosity is very important property. According to Darcy Equation, This factor can influence the petroleum or gas migration in the ground.

5) (Section 4 – Results) the calculation results shown in the results section should be validated against previous publications.

6) (Line no. 613) the heading of section 5 should be moved to the following page. 

7) (Section 6 – Conclusion) as was stated at the end of the introduction section, the authors should address the issue the deployment of oil and gas exploration in the Qiongdongnan and Yinggehai basins.

8) (References section) the year should be bold (See the following reference example):

Author 1, A.B.; Author 2, C.D. Title of the article. Abbreviated Journal Name Year, Volume, page range, DOI.

Author Response

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Reviewer 3 Report

This is a very well-written manuscript.

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Round 2

Reviewer 2 Report

Dear Authors,

Thank you very much. The calculated porosity of the sand obtained in this work compared favorably with the literature results. The time duration sequence of QDNB in [Ma] is similar to the time duration sequence reported in the literature (see figure 2). It is recommended to accept this useful paper for publications after performing the following minor revisions: (Line no. 158) the MATLAB software version should be described and refenced inside the list of references. Reference [14] - The publication year of this mentioned paper is 2016 and not 2018 as written.  it recommended to cite the following website: Li Guoqiang, China Sea Oil and Gas Resources, China International Studies (CHS),  https://www.ciis.org.cn/english/COMMENTARIES/202007/t20200715_2762.html 

Author Response

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