Assessment of the Biogenic Souring in Oil Reservoirs under Secondary and Tertiary Oil Recovery
, Wolfgang Jelinek 5 and Mohd Amro 1Round 1
Reviewer 1 Report
Comments and Suggestions for Authors1. In the abstract part, make sure that all the entities mentioned, such as "H2S" and "SRMs", have clear full names for non-professional readers to understand.
2. In this paper, the phenomenon of biogenic acidification and its risks in oil and gas exploitation are comprehensively reviewed, and several key research and pioneering work are cited. However, the integration of the latest research progress can be further strengthened to ensure the timeliness and completeness of literature review.
3. The metabolic process of sulfate reducing bacteria (SRB) and other microorganisms using different substrates and how to affect the production of H2S are described in detail, but the changes of microbial community in specific environment can be further clarified. Increase microbial ecological information under specific reservoir conditions.
4. Although the article focuses on the technical level, it does not fully discuss the environmental impact of chemical inhibitors. It is suggested that environmental impact assessment be added.
5. Based on the existing knowledge, the research provides practical workflow and evaluation tools, but it is not innovative in theory or method. It is suggested that future research should be encouraged to explore more novel solutions.
6. The conclusion of the article summarizes the main findings and puts forward the future research direction, but the discussion on the limitations of the current research is not deep enough. It is suggested to strengthen the exposition of limitations and future research direction.
7. Although the model and method used are mentioned, there is a lack of specific experimental details and detailed description of data analysis steps. It is suggested to provide supplementary materials or briefly introduce key experimental parameters and methods in the text so that readers can reproduce the research.
8. In line 22 of page 1, when discussing the inhibition effect of molybdate in detail, add the data compared with other inhibitors to highlight its advantages.
9. In line 54 of page 2, for the continuous discussion on nitrate application, it is necessary to summarize the current viewpoints and point out the focus of controversy.
10. On page 2, line 55, the alternative mitigation chemicals and methods mentioned should be listed with specific examples to increase the practicality of the information.
11. In line 57 of page 2, when the importance of predicting and evaluating the influence of biogenic acidification on production performance is emphasized, practical cases can be added to support the argument.
12. In line 60 of page 2, it is suggested to provide specific practical strategies or guidelines for the scarce practical reservoir engineering perspective.
13. In line 11 of page 1, it is suggested that the definition of "biogenic acidification" should be clarified, and its specific harm to the petroleum industry should be briefly explained.
Comprehensive consideration, based on the above comments, the overall quality of the article is high, which has certain scientific value and application prospects. It is suggested that it be accepted for publication after appropriate revision and improvement.
Comments on the Quality of English Languageits ok
Author Response
Thank you very much for taking the time to review this manuscript. Please find the detailed responses and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsBiogenic souring is a common risk in secondary (waterflooding) and tertiary oil production (EOR) operations. This paper reviews the latest progress of biogenic reservoir acidification, control parameters and mitigation measures. A combination of water flooding and microbial enhanced oil recovery techniques to validate the mechanisms and effects of biological acid on reservoir oil recovery, assess H2S from microbial interactions, assess parametric uncertainty using Monte Carlo methods, and propose and discuss workflows that can be used in similar studies to assess the risk of biogenic rancidity and potential mitigation measures. Suggestions as follow:
1. Table 1 mentions numerous static and dynamic assessment methods. What are the differences or references from the mineralogical analysis of siderite rocks in section 3.3.5?
2. In part 3.3.2, “Laboratory data and unpublished field data indicate that the levels of H2S that can be generated in high salinity brines (TDS of higher than 150 g/L) are lower compared to equivalent lower salinity brines.” What is the classification standard of high salinity brine?
3. Page 19, lines 634-637, “Mineral scavenging, sulfate content of injection water and injection rates were selected as sensitive parameters and entered to a Monte Carlo uncertainty analysis as statistical distributions between the minimum and maximum values estimated from lab and field data.” What is the selection basis?
4. In Chapter 6, in addition to an overview of the inhibition of nitrate, nitrite and molybdate on microbial sulfate reduction, the defects of various inhibitors are also introduced. However, in the current description, these mechanism analyses are slightly inadequate. In order to deepen readers' understanding, it is suggested to add or combine more detailed mechanism analysis to make the content richer and deeper, so as to have a more comprehensive understanding of this field.
5. Chapter 7 mentioned that Kalpakci et al. described a decision-making strategy relatively early, the author makes a detailed introduction to the assessment of biogenic souring and its mitigation. Is this decision-making strategy used for reference? Where is its optimization reflected?
6. This paper puts forward the work flow of assessing and managing biogenic souring in oil reservoirs during secondary and tertiary, and the conclusion should be briefly explained.
Author Response
Thank you very much for taking the time to review this manuscript. Please find the detailed responses and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.
Kind regards
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe author has revised the whole article according to the requirements, and it is recommended to accept this article.
