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  • Haiwen Chen1,
  • Feng Zheng1 and
  • Rongcai Song1,2,*
  • et al.

Reviewer 1: Yilong Yuan Reviewer 2: Marco Pola Reviewer 3: Muralitharan Jothimani

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this work, the author comprehensively collated drilling, geological, and geophysical data to quantitatively analyze the geometric, thermal, and physical properties of the Huangliu Formation's thermal reservoirs, delineating regions with superior geothermal resources. The results presented in this work can provide support for deepening the understanding of the characteristics of the Huangliu Formation thermal reservoir in the Yinggehai Basin and for the development and utilization of offshore geothermal resources. However, the novelty of this work is not well presented. It is suggested to clarify the novelty of this work compared with others in section 1. To further enhance the quality and readability of the manuscript, I propose the following suggestions: 

1. Refine the Abstract: The abstract should succinctly summarize the importance of geothermal energy, the research objectives, the primary methods, and the key findings. 

2. Establish a Methodological Framework: Given the variety of methods employed by the authors, it is recommended to include a concise overview of the entire methodology within the manuscript. Clearly outlining the steps involved in geothermal resource assessment will aid readers in quickly grasping the overall structure of the research approach. 

3. Optimize Figure Information: Enhance the clarity of the figures by increasing the size of key graphics, such as the Monte Carlo simulation results (Figure 9). This will improve readability and facilitate the interpretation of the data presented. 

4. Expand Literature References: Broaden the scope of literature citations, especially in the methodology description and results discussion sections (Chapter 4). Ensuring that each method and finding is supported by appropriate references will enhance the credibility and scholarly value of the research. 

5. Some Figures are not clear, e.g., Figure 1, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9, Figure 10. The font size indicated in the figure needs to be larger. 

6. Conclusions drawn in this study is apparent. The section can be condensed and refined.

Comments on the Quality of English Language

The English writting is ok, but minor editing is required.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Associate Editor and Authors,

I reviewed the manuscript titled “Geothermal Resource Assessment and Development Recommendations for the Huangliu Formation in the Central Depression of the Yinggehai Basin” from Chen et al. The manuscript details the distribution of the geothermal resources in the Huangliu formation within the Yinggehai Basin. Furthermore, it estimates the amount of thermal energy stored in the aquifer with volumetric models and Monte Carlo simulations determining the most prospective locations for the thermal energy extraction.

The results presented in the manuscript are interesting and the methodological approach is multi-fold representing a good case study in the literature of geothermal resources potential estimation. However, the manuscript is often confused, with parts that are redundant or wordy, and mixing methods and results. Several different methodological approaches are used in this work and sometimes it is difficult to clearly separate the single method from its result. Still, a separation is needed to better follow the manuscript. Furthermore, the figures are too small and difficult to read and are missing some key points that could help the Reader in the comprehension of the results.

Here are my general comments:

·       please add line numbering in the text. This will make the manuscript easier to review.

·       numbering of chapters and subchapters need to be revised.

·       an overall methodology of the work is missing. The Authors are: i) assessing the thermal setting of the study area with reinterpretation of available data and numerical modeling, ii) delineating the geometry of the reservoir, its temperature distribution, and its physical properties with geological reconstruction and mapping, iii) assessing the energy stored in the reservoir using with volumetric estimations and Monte Carlo simulations, and iv) determining the more perspective resources with the TOPSIS method. An initial, general, workflow describing all these steps could help the Reader in following the logic of the manuscript. The methodological approach should be described after the chapter “2. Regional Geothermal Geological Background”. A figure could support the description.

·       the methods used in points 1 and 2 of the previous list are generally lacking and sometimes it is not clear if the presented results are new or taken from the literature. For example: i) in the chapter “3. Present-day geothermal field in Yinggehai Basin”, the Authors state that they performed the Horner correction for correcting the temperature from Modular Formation Dynamics Tester measurements, but the Reader could not be familiar with this methodology, ii) in the chapter “3. Present-day geothermal field in Yinggehai Basin”, the Authors state that “a two-dimensional finite element method was employed to simulate the deep temperature field of the central depression of the Yinggehai Basin”, however it is not clear how was this model constructed, which are the boundary and initial conditions, the parameters of the formations, which software was used to run the simulations, iii) in the chapter “3.2. Temperature of the Huangliu Formation Geothermal Reservoir”, new radiogenic heat production and rock thermal conductivity data are used for the calculation of the temperature distribution, but it is not described how were these data were obtained. Many other remarks on the lack of methodology are reported in the revised pdf version of the manuscript.

·       the methods for the energy estimation and for assessing the most perspective resources are described, but they are mixed within the results. A clear separation is needed. I reported detailed comments on this topic in the revised pdf version of the manuscript.

·       all the methodologies described in the text should be constrained with literature references. In particular, the Reader could be interested to know if they are generally used in the investigation of thermal resources. Sometimes, I highlighted it in the revised pdf version of the manuscript, but references are needed in many other parts of the text.

·       the figures are sometimes difficult to read because they are too small. Some general comments on the figure: i) a geographical map is shown in Figure 1, but it is too small and geographical references (cities, provinces, coordinates) are missing, ii) all the maps reporting the geothermal gradient, the heat flux, the temperature distributions, the thickness of the reservoir should be enlarged since they are the foundation for all other calculations, iii) the Authors are referring to sections of the geothermal reservoir (R01-R26), but the positions of these sections are not shown in a map, iv) the results of Monte Carlo simulations for the sections of the reservoir (Figures 8 and 9) are way too small and they are impossible to read. In my opinion, points 1 and 3 of the list are paramount since they would help the Reader to spatially locate the study area (point 1) and to follow the results of the work that are all based on the delineation of the reservoirs. Regarding point 4, I suggest enlarging the insets of Figure 8, while the results in Figure 9 could be reported as supplementary material since the results of the Monte Carlo simulations are numerically described in Table 5.

·       the captions of all figures should be slightly extended making them more informative and descriptive.

·       the text is sometimes wordy and imprecise terminology is used. I added some comments in the revised pdf version of the manuscript.

These and other comments are reported in the revised pdf version of the manuscript. Unfortunately, I couldn’t make any corrections on the Word file since it was not provided nor I could refer my comments to specific lines since they were not present.

Best regards,

Marco Pola

Comments for author File: Comments.pdf

Comments on the Quality of English Language

My comments on the quality of the English language are embedded within the general comments and suggestions for the Authors, as well as in the attached revised pdf version of the manuscript.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The paper discussing the Geothermal Resource Assessment and Development Recommendations for the Huangliu Formation in the Central Depression of the Yinggehai Basin seems technically sound. However, a few potential areas might require clarification and improvement.

Abstract

Mention of the significance of geothermal energy in global and regional contexts.

State the main objectives of the study.

Include a short description of the main methodologies used in the study.

Highlight the most critical findings and their implications.

Introduction

Identify the specific gaps in existing research that this study aims to address.

Write a clear statement of the study's objectives and research questions.

Briefly outline the scope of the study and any inherent limitations.

Methodology

Include detailed descriptions of all data sources and how they were obtained.

Explain how different data types were integrated.

Mention the methods used to validate the data and results.

Geothermal Field Analysis

Compare with geothermal fields in other regions to contextualize findings.

Discuss uncertainties in the geothermal gradient and heat flow measurements.

Acknowledge any limitations in the data used for analysis.

Results and Discussion

Interpretate the results in the context of existing literature.

Discuss the broader implications of the findings for geothermal energy development.

Compare the results with similar studies in other basins.

Suggest future research directions based on the findings.

Conclusion

Write a concise summary of the study's main findings.

Write detailed practical implications of the findings for policymakers and industry stakeholders.

 

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The author have solved most of my comments. However, some Figures are still not clear. The font size indicated in the figure needs to be larger.

Author Response

Thank you for pointing this out. I agree with this comment. Therefore, I have increased the font size in the figures to ensure clarity. Specifically, the changes have been made in Figures 3, 5, and 6.

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Editor,

I checked the revised version of the manuscript “Geothermal Resource Assessment and Development Recom-2 mendations for the Huangliu Formation in the Central Depres-3 sion of the Yinggehai Basin” by Chen et al. The Authors addressed my comments. I have some minor suggestions:

·        Spaces between words or in-text citations are sometimes missing.

·        Some in-text citations are in yellow.

·        L. 141: instead of “Geothermal gradient characteristics”, I suggest “Geothermal gradient distribution”.

·        L. 152: repetition of text.

·        L. 170: as the comment for L. 141.

·        L. 358: I suggest “the Oracle Crystal Ball software”. Appropriate references should be added.

Author Response

Thank you for pointing this out. We agree with this comment. Therefore, we have made the following changes:

  1. We have checked and supplemented the missing spaces between words and in-text citations throughout the manuscript.
  2. The yellow highlights within the text have been removed.
  3. Lines 141 and 170 have been revised to "Geothermal gradient distribution" and "Distribution of heat flow," respectively.
  4. The repetitive text in Line 152 has been rewritten.
  5. Regarding Line 358, we apologize for not fully understanding your suggestion to change it to "Oracle Crystal Ball software." The specific use of this software is detailed in Line 398. We have made the necessary changes and added the appropriate reference [55] at this location. If you believe the modification should be made at Line 358, please provide further clarification, and we will be grateful for your assistance.