Synthesis of an Eco-Friendly Xylooligosaccharides and Its Mechanistic Evaluation in Water-Based Drilling Fluids

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Author,

- The article describes an important issue regarding the sustainability of chemicals used in drilling oils when drilling large earth wells.
With regard to the environmental hazards of petroleum-based chemicals, it is particularly important to find substitutes that do not cause harm to the environment but still provide the technical performance of a drilling oil.
- The author describes a class of oligosaccharides that are both easy to produce (from natural substances) and rapidly degradable if left in nature. The only point to be scientifically clarified is the technical performance, i.e. the comparison to synthetic additives, their applicability (temperature range) and their effectiveness. The author conducts these investigations on the basis of comparative measurements with existing products.
- The article complements very well existing publications in this field (on sustainable additives), because the class of oligosaccharides still provides a wide field of possible candidates. Other publications use soaps, glycerol derivatives, chitins, etc., but the variance of possible natural substances requires many more publications on potential substitutes, because the entire interaction of the various components of drilling oils requires many more investigations, which cannot be covered in one publication.  
- The tables and figures show the technical potential of oligosaccharides on the basis of the measured values.
For the future, of course, many more measurements will be necessary to investigate the interaction with other additives in drilling oils (service life, dispersibility with different additives, more tests on real drilling oils with real muds).  
- This article can only be a first start for the study of these oligosaccharides. More investigations must follow and, as mentioned, the interactions with the other additives must be scientifically deepened.
- Also, much more mechanistic investigations must follow to prove and understand the interaction with the clay minerals, in order to then be able to make predictions as to which chemical structures will lead to which effects with the clays (building up of the important hydrophobic intermediate layer between mineral and aqueous phase).

 

Author Response

Comment 1: The article describes an important issue regarding the sustainability of chemicals used in drilling oils when drilling large earth wells. With regard to the environmental hazards of petroleum-based chemicals, it is particularly important to find substitutes that do not cause harm to the environment but still provide the technical performance of a drilling.

Response: We appreciate the reviewer's recognition of the importance of the sustainability aspect discussed in our article. Ensuring the sustainability of chemicals used in drilling fluids for large earth wells is indeed a critical concern, given the environmental impact of drilling operations. Our research aims to address this issue by introducing an eco-friendly additive, Xyloligosaccharides (XOS), and examining its potential to enhance the sustainability of water-based drilling fluids (WBFs). We hope that our findings will provide valuable insights into more environmentally responsible drilling practices.

Comment 2: The author describes a class of oligosaccharides that are both easy to produce (from natural substances) and rapidly degradable if left in nature. The only point to be scientifically clarified is the technical performance, i.e., the comparison to synthetic additives, their applicability (temperature range) and their effectiveness. The author conducts these investigations on the basis of comparative measurements with existing products.

Response: Thank you for your suggestion. We agree that comparing our results with other published literature to identify similar findings and trends would be valuable. We will conduct a comprehensive literature review to identify relevant studies and compare our results with those findings. This will help provide a broader context for our research and highlight the significance of our results in the existing body of knowledge. We appreciate your feedback and will incorporate this into our manuscript, including the addition of necessary references and highlighting them in yellow to emphasize their relevance. This will strengthen the manuscript and provide a better context for the significance of our research.

Comment 3: The article complements very well existing publications in this field (on sustainable additives), because the class of oligosaccharides still provides a wide field of possible candidates. Other publications use soaps, glycerol derivatives, chitins, etc., but the variance of possible natural substances requires many more publications on potential substitutes, because the entire interaction of the various components of drilling oils requires many more investigations, which cannot be covered in one publication.

Response: We appreciate the reviewer's recognition of the complementarity of our article to existing publications on sustainable additives. The broad spectrum of natural substances, including oligosaccharides, offers a rich area for potential alternatives. As pointed out, the complexities of interactions within drilling fluids necessitate ongoing investigations, which cannot be comprehensively covered in a single publication. We would like to emphasize that our study on Xyloligosaccharides (XOS) in drilling fluids is part of an ongoing research effort. While this article provides valuable insights into XOS's performance, we recognize that there is much more to explore in this field. Therefore, we are committed to continuing our research on XOS in drilling fluid systems, and we intend to delve deeper into its applicability, mechanisms, and potential variations in future articles. We believe that this ongoing research will contribute to a more comprehensive understanding of sustainable additives and their role in environmentally responsible drilling practices.

Comment 4: The tables and figures show the technical potential of oligosaccharides on the basis of the measured values. For the future, of course, many more measurements will be necessary to investigate the interaction with other additives in drilling oils (service life, dispersibility with different additives, more tests on real drilling oils with real muds). This article can only be a first start for the study of these oligosaccharides. More investigations must follow and, as mentioned, the interactions with the other additives must be scientifically deepened. Also, much more mechanistic investigations must follow to prove and understand the interaction with the clay minerals, in order to then be able to make predictions as to which chemical structures will lead to which effects with the clays (building up of the important hydrophobic intermediate layer between mineral and aqueous phase).

Response: We appreciate the insightful comments and agree with the reviewer's observations regarding the scope and potential of our study on oligosaccharides in drilling fluids. Indeed, our research represents an initial exploration into the technical potential of oligosaccharides as sustainable additives. As the reviewer correctly points out, there is much more work to be done in this area to comprehensively understand their interactions with other additives, service life, dispersibility in different conditions, and their performance in real drilling scenarios with authentic mud compositions. We acknowledge the need for further investigations, especially mechanistic studies, to provide a deeper understanding of how oligosaccharides interact with clay minerals and other components in drilling fluids. This will not only help predict the effects of different chemical structures on clay interactions but also contribute to the development of tailored additives for specific drilling conditions. We are committed to expanding our research efforts in this direction and will explore these aspects in future studies. The feedback provided by the reviewer is valuable, and we share the view that this is just the beginning of a promising avenue of research with significant potential for sustainable drilling practices.

Reviewer 2 Report

Comments and Suggestions for Authors

It is a very interesting work, its content constituting research for the future. The use of XOS in water-based drilling fluids is innovative, and the presented scope of study complements the literature on this topic.

The submitted manuscript is rich in research and relatively well described. For completeness, it is essential to complete a few important points:

1. Line 99. Concerns about the materials, specifically the black fungus used. The authors wrote that they procured them from Metro Supermarket. How is freedom from contamination ensured, which may vary depending on where it is purchased? Any contamination affects the correctness and repeatability of the results. Have the Authors investigated this issue?

2. Line 108. Is the sample preparation procedure standardized? How finely crushed should samples of black fungus be? Where are the sample preparation parameters selected from?

3. Line 131. Each formula should be marked separately.

4. Line 239. In Chapter 3.2.3, there is no commentary on the results included in the table. The chapter consists of only two tables. The description is in the next chapter. This arrangement is confusing. I suggest combining the chapters or placing the description of the lubrication performance test results in a chapter along with the results.

5. Line 241. There is an unfinished table description there. To remove.

6. Line 242. Table 3 contains the "reduction rate from friction coefficient" parameter. For what conditions was this parameter given, and on what basis can we talk about reduction? How it was calculated: I have not yet obtained such indicators in % based on the data from the table.

7. Line 331. The conclusions lack a connection between all the obtained research results and an attempt to find a relation resulting from administering a specific amount of % XOS. I consider the conclusions incomplete.

8. General question 1. The manuscript presents research from various areas and also uses a graphic method. None of the charts constitute statistics. Hence, the question arises of how many times and whether the studies were repeated at all. What is the repeatability of test results? (this is somewhat related to point 1 regarding crushing black fungus).

9. General question 2. What is the efficiency of the fluid with the addition of XOS, and what are the properties of the fluid produced and used?

 

In my opinion, the paper should solve all the above topics before publication.

Author Response

Comment 1: Line 99. Concerns about the materials, specifically the black fungus used. The authors wrote that they procured them from Metro Supermarket. How is freedom from contamination ensured, which may vary depending on where it is purchased? Any contamination affects the correctness and repeatability of the results. Have the Authors investigated this issue?

Response: We appreciate the reviewer's concern regarding the source of the black fungus used in our study. Ensuring the quality and freedom from contamination of materials is indeed crucial for the accuracy and repeatability of research results. In our study, we procured black fungus samples from Metro Supermarket. While we took care to select high-quality and uncontaminated samples, we understand the importance of verifying the quality and potential for contamination of the materials used in research. To address this concern, we conducted initial inspections to visually assess the samples for any visible signs of contamination or impurities. Additionally, we employed standard laboratory procedures for sample preparation, including washing, grinding, and filtration, to minimize the risk of contamination. However, we acknowledge that further analysis and verification of material quality, such as microbial testing or chemical analysis, could provide additional confidence in the material's purity. In future research, we will consider implementing such quality assurance measures to ensure the reliability of our results. Thank you for raising this important point, and we will take it into account for our future work.

Comment 2: Line 108. Is the sample preparation procedure standardized? How finely crushed should samples of black fungus be? Where are the sample preparation parameters selected from?

Response: In the process of sample preparation, the first step of coarse crushing of black fungus samples is not crucial. We use the final step of crushing and a 200-mesh sieve for screening. We consistently follow this step in all sample preparation procedures to ensure that the samples are uniformly crushed to minimize variability. The parameters of the sample preparation program were selected based on standard laboratory practice and our research objectives. The current crushing particle size mainly ensures that the sample can be quickly dispersed in the drilling fluid base mud to ensure subsequent experiments. In future research, we will consider providing more detailed information on the particle size or fineness obtained during sample preparation to improve the transparency and reproducibility of our method. Thank you for emphasizing this aspect, and we will take it into account in our future work.

Comment 3: Line 131. Each formula should be marked separately.

Response: Thank you for your comment. Marking each formula separately can improve the clarity and readability of the document. Here's the revised section with separate markings for each formula:

	(1)
	(2)
	(3)

Comment 4: Line 239. In Chapter 3.2.3, there is no commentary on the results included in the table. The chapter consists of only two tables. The description is in the next chapter. This arrangement is confusing. I suggest combining the chapters or placing the description of the lubrication performance test results in a chapter along with the results.

Response: Thank you very much for pointing out this issue. Due to an error in converting the formatting, the discussion of the experimental results in the table was mistakenly pasted at the bottom of Figure 4. This error has now been corrected.

Comment 5: Line 241. There is an unfinished table description there. To remove.

Response: Thank you very much for pointing out this error. We have removed the unfinished table.

Comment 6: Line 242. Table 3 contains the "reduction rate from friction coefficient" parameter. For what conditions was this parameter given, and on what basis can we talk about reduction? How it was calculated: I have not yet obtained such indicators in % based on the data from the table.

Response: In Tables 2 and 3, the reduction rate from the friction coefficient is determined by comparing the friction coefficient in the base mud to the friction coefficient after the introduction of XOS. For instance, at 25°C, the friction coefficient of the base mud without XOS is 0.9030, while the friction coefficient decreases to 0.3336 upon the addition of XOS. Thus, the reduction rate from the friction coefficient can be calculated as 1 - (0.3336 / 0.9030) = 0.6306, resulting in a reduction rate from the friction coefficient of 63.065%. The same algorithm was used to calculate the reduction rate from the friction coefficient in other rows of Tables 2 and 3. We believe that calculating the reduction rate can more intuitively demonstrate the lubrication performance of XOS.

Comment 7:  Line 331. The conclusions lack a connection between all the obtained research results and an attempt to find a relation resulting from administering a specific amount of % XOS. I consider the conclusions incomplete.

Response: Thank you very much for your comment. We have revised the conclusion section based on your comment. We will further characterize the mechanism of XOS through more experiments and explore its performance in various drilling fluid systems. This will help establish a more comprehensive connection between XOS concentration and its impact on drilling fluid properties, and provide more complete and detailed conclusions. We attach great importance to your suggestion and will strive to provide more valuable research results.

Comment 8: The manuscript presents research from various areas and also uses a graphic method. None of the charts constitute statistics. Hence, the question arises of how many times and whether the studies were repeated at all. What is the repeatability of test results? (This is somewhat related to point 1 regarding crushing black fungus).

Response: Thank you for raising the question regarding the repeatability of our test results. We understand the importance of ensuring the reliability of our findings. In our study, we conducted multiple repetitions of experiments to enhance the robustness and reliability of the results. However, we acknowledge that a more detailed description of the repeatability and statistical analysis of our experiments should be included in the manuscript to provide a clearer picture of the reliability of our findings. In future work, we will make sure to include this information to address this important aspect of our research. We have supplemented the existing error experimental results and redrawn the analysis diagram in the revised manuscript, as shown in Figures 3 and 4, revised as follows:

Comment 9: General question 2. What is the efficiency of the fluid with the addition of XOS, and what are the properties of the fluid produced and used?

Response: Thank you for your question regarding the efficiency of the fluid with the addition of XOS and the properties of the fluid used in our study. In our current manuscript, we primarily focused on the characterization of the XOS additives and their impact on friction reduction. However, we understand the importance of evaluating the overall efficiency and properties of the drilling fluid with XOS additives. We plan to conduct a more comprehensive analysis that includes the evaluation of fluid efficiency, rheological properties, and other relevant characteristics of the drilling fluid when XOS additives are incorporated. This will allow us to provide a more holistic understanding of the performance of XOS in drilling fluid systems. Thank you for highlighting this aspect, and we will work on addressing it in our future work.

Reviewer 3 Report

Comments and Suggestions for Authors

Title: Synthesis of an Eco-friendly Xylooligosaccharides and its Mechanistic Evaluation in Water-based Drilling Fluids

Article Type: full article

Manuscript Number: sustainability-2582215-v1

 

In this article the preparation and application mechanism of Xylooligosaccharides additive that derived from black fungus in water-based drilling fluids. XOS emerges as a versatile and sustainable oligosaccharide inhibitor which effectively optimizing the performance of WBFs. XOS emerges as a versatile and sustainable oligosaccharide inhibitor, effectively optimizing the performance of WBFs that diverse contributions to lubrication, inhibition, and microstructure refinement position XOS as a promising solution for efficiently extracting oil and gas resource.

 

 My recommendation is that the authors carefully consider the below points, revise appropriately.

1. Page 3 line 100; the authors show that the black fungus used in this experiment came from supermarkets and was either fresh black fungus or dried black fungus. Do the samples have been tested to confirm that there are no other chemical additives.

2. My suggestion is that the authors check the full text for grammar and symbols with appropriate software. For example, the symbol of the wavenumber is inconsistent with the symbol in lines 171~184 on page 5 and Figure 1.

3. My suggestion is that authors must write in accordance with the requirements of the journal, in a format that has already been published in a similar article in the journal. Particularly, the brand and purity of each drug must be clearly labeled. In particular, the references section must be carefully revised.

4. My suggestion is whether the authors can compare other published literature to find results similar to this study. For the result is very interesting and valuable.

5. My suggestion is that the authors compare this study with similar articles that have been published in the past and highlight the superiority of this study.

Comments on the Quality of English Language

The authors must write in accordance with the requirements of the journal, in a format that has already been published in a similar article in the journal. Particularly, the references section must be carefully revised.

Author Response

Comment 1: Page 3 line 100; the authors show that the black fungus used in this experiment came from supermarkets and was either fresh black fungus or dried black fungus. Do the samples have been tested to confirm that there are no other chemical additives.

Response: Thank you for your question regarding the black fungus samples used in our experiment. While we procured the black fungus from supermarkets, we acknowledge the importance of ensuring that the samples are free from any chemical additives or contaminants that could affect the experiment's integrity. In our study, we visually inspected the black fungus samples to ensure they were of high quality and did not appear to have any obvious chemical additives. However, we did not conduct specific chemical testing to confirm the absence of additives. To address this concern and ensure the validity of our results, we plan to include a section in our future research where we analyze the black fungus samples for potential chemical additives or contaminants. This additional step will provide a more comprehensive understanding of the samples used in our experiments. Thank you for bringing this issue to our attention.

 

Comment 2: My suggestion is that the authors check the full text for grammar and symbols with appropriate software. For example, the symbol of the wavenumber is inconsistent with the symbol in lines 171~184 on page 5 and Figure 1.

Response: Thank you for your suggestion regarding the consistency of symbols in our manuscript. We apologize for any inconsistencies, and we appreciate your attention to detail. We will carefully review the manuscript to ensure that all symbols, including the wavenumber symbol, are used consistently throughout the text, figures, and equations. Additionally, we will use appropriate software to check for any grammar or formatting issues to improve the overall quality of the manuscript. Your feedback is valuable, and we will take steps to address these concerns in the final version of the manuscript.

 

Comment 3: My suggestion is that authors must write in accordance with the requirements of the journal, in a format that has already been published in a similar article in the journal. Particularly, the brand and purity of each drug must be clearly labeled. In particular, the references section must be carefully revised.

Response: Thank you for your suggestion regarding adhering to the journal's requirements and formatting guidelines. We will ensure that the manuscript is revised to meet the specific formatting and labeling requirements of the journal, including providing clear information about the brand and purity of each drug or substance used in the study. Additionally, we will carefully review the references section to ensure accuracy and compliance with the journal's guidelines. Your feedback is valuable, and we will make the necessary revisions to ensure that the manuscript meets the journal's standards.

Comment 4: My suggestion is whether the authors can compare other published literature to find results similar to this study. For the result is very interesting and valuable.

Response: Thank you for your suggestion. We agree that comparing our results with other published literature to identify similar findings and trends would be valuable. We will conduct a comprehensive literature review to identify relevant studies and compare our results with those findings. This will help provide a broader context for our research and highlight the significance of our results in the existing body of knowledge. We appreciate your feedback and will incorporate this into our manuscript. We have added the necessary references and highlighted them in yellow in the revised manuscript.

 

Comment 5: My suggestion is that the authors compare this study with similar articles that have been published in the past and highlight the superiority of this study.

Response: Thank you for your suggestion. We have revised the introduction section of the manuscript and have included a comparison of this study with similar articles that have been published in the past. We have highlighted the superiority of our study in this context and have used yellow highlighting to emphasize this content. We appreciate your feedback, and we hope that this addition strengthens the manuscript and provides a better context for the significance of our research.

Reviewer 4 Report

Comments and Suggestions for Authors

I found the paper interesting to read and enjoyed it. The topic is relevant to the field and found it novel. And tries to enhance interest in drilling fluids field of study.

The abstract should be modified to one paragraph. 

The authors should quantify the extraction yield and purity of XOS?

Would it be possible to obtain the steady-shear viscosity at modified temperatures?

Would it be possible to obtain the TGA of loaded XOS at varied concentrations in Mud Cake samples corresponding to Figure 5?  

Also, the references cited are inadequate and not the latest.

The presented article can be recommended for publication with major revisions in the journal "Sustainability". 

Comments on the Quality of English Language

Moderate editing of English language required

Author Response

Comment 1: The abstract should be modified to one paragraph.

Response: Thank you for your feedback. We will revise the abstract to make it a single paragraph to better adhere to the journal's formatting guidelines.

Comment 2: The authors should quantify the extraction yield and purity of XOS?

Response: Thank you for your valuable input. Through this study, we have primarily explored the fundamental performance of XOS as a single additive in water-based drilling fluid formulations, including its lubrication, inhibition, rheological, and filtration control properties. However, investigating and quantifying the relationship between the components of natural plant extracts and their performance is a challenging task. In our future work, we will take your suggestion into account and thoroughly examine the specific effects of different components within the Auricularia polysaccharide extract on various performance aspects, conducting quantitative experiments. In our preliminary experiments, we observed that XOS exhibits a higher resistance to elevated temperatures compared to other natural sugar-based treatment agents. This can be attributed mainly to the relatively high thermal stability of Auricularia polysaccharides present in XOS. The unique molecular structure and composition of Auricularia polysaccharides, characterized by abundant branching structures, cyclic molecules, and cross-linking structures, as well as the presence of hydrogen and covalent bonds, collectively contribute to the stability of these polysaccharides. This makes them less susceptible to degradation or denaturation under high-temperature conditions. However, it's important to note that these potential mechanisms will require further extensive research for confirmation in future studies. Your insightful feedback is greatly appreciated, and we will strive to explore and elucidate these mechanisms in our forthcoming research endeavors.

 

Comment 3: Would it be possible to obtain the steady-shear viscosity at modified temperatures?

Response: Thank you for your suggestion. Investigating the steady-shear viscosity at modified temperatures could provide further insights into the temperature-dependent rheological properties of the drilling fluids with XOS additives. We will explore the feasibility of conducting additional experiments at different temperatures and the results in the next manuscript on the XOS mechanism research.

 

Comment 4: Would it be possible to obtain the TGA of loaded XOS at varied concentrations in Mud Cake samples corresponding to Figure 5?

Response: Thank you for your suggestion. Obtaining the TGA (Thermogravimetric Analysis) data for loaded XOS at varied concentrations in Mud Cake samples is an interesting idea. This additional data could provide valuable insights into the thermal stability and behavior of the mud cake with different XOS concentrations. We will explore the feasibility of conducting additional experiments at different temperatures, and if we can improve the comprehensiveness of the study, we will include the results in the next manuscript on the XOS mechanism research.

 

Comment 5: Also, the references cited are inadequate and not the latest.

Response: We appreciate your feedback and will incorporate this into our manuscript. We will review and update the references to ensure that the most recent and relevant sources are cited in the manuscript. This will help strengthen the background and support for our research. We have added the necessary references and highlighted them in yellow in the revised manuscript.

Round 2

Reviewer 4 Report

Comments and Suggestions for Authors

It can now be accepted for publication.

Comments on the Quality of English Language

Minor editing of English language required