Fractional Flow Analysis of Foam Displacement in Tight Porous Media with Quasi-Static Pore Network Modeling and Core-Flooding Experiments
, Iftekhar Ahmed Shakib 1, Zeyu Lin 3, Yunan Song 1, Yanfeng He 1, Bo Zhang 4,* and Jing Zhao 1,2,*
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis manuscript is overall well-written and well-organized. A few comments are listed below:
1) From Figure 9 to 15, I wonder if it is possible for author to add lines across to show the trend since some points are mixing together, making it difficult to distinguish the trend.
2) For tight reservoirs, hydraulic fracturing is usually used to improve oil production. Does author will consider this in the experiment in the future? I suggest to add a section to talk about future work.
3) What are advantages and limitations of this work?
Author Response
The author response letter is attched.
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Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThis paper provides a comprehensive study on fractional flow profiles of foam displacement processes, including the theoretical study inside microscale pore network, and experimental study inside mesoscale tight core samples. There are several defects in manuscript authors can revise to improve the overall quality.
1. Line 115 to line 121: Distribution and identification of trapped wetting phase is key issue in pore network modeling. Please summarise relevant trapping rule in the assumptions.
2. Line 145-147: Please make further explanations on the reason of why leave-behind do not make additional contribution to the accumulation of foam flowing threshold.
3. Figure 6: Please explain why the fractional flow calculation has only done once after the maximum gas saturation being reached. Shouldn’t it be included in the main loop of the process?
4. Line 275-280: Please provide more detailed properties of two core samples used in this work.
5. Line 156: Please correct the typo in the manuscript like Rt here.
6. Line 174-175: Please provide more detailed explanation on the reason remove F and G from the candidate list.
Author Response
Please see the detailed response letter in the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe aim of this present paper is to investigate the characteristics of foam displacement inside the tight porous media with varying absolute permeability, injection rate, and foam quality via the fractional flow analysis with the pore-scale simulation study and the core-scale experimental work. While the authors have conducted a series of works, the manuscript lacks deep key discussions, particularly in relation to the paper's key research goals. Therefore, the paper needs necessitating substantial revisions. There are several aspects that need clarifying or more detail added to strengthen this article.
1. The title of this manuscript needs to be renamed, and the adjective word-mesoscale can be removed.
2. Abstract needs to be enhanced to address key results and important findings of novelty accordingly.
3. The introduction needs some rephrasing to be more clear. Especially, add more detailed scientific contents on fractional flow analysis and quasi-static pore network modeling. And add more relevant literatures in recent years, such as “Imbibition behavior of oil-saturated rock: Implications for enhanced oil recovery in unconventional reservoirs”, “Rock fabric of lacustrine shale and its influence on residual oil distribution in the Upper Cretaceous Qingshankou Formation, Songliao Basin”.
4. Figures and tables of this manuscript should be improved. Revise all of your figures and tables to increase the normativity and readability according to guidelines of the host journal.
5. Line 262 of page 9, ‘The experimental apparatus of core flooding test is shown in Figure 7’ is not corrected due to the lack of period, please revise it. Carefully check these low-level mistakes throughout the manuscript. Too many low mistakes existed in the submitted manuscript, such as ‘CO2’ and ‘(250cc, Teledyne ISCO)’.
6. Section 4 (Results and discussion), it is too descriptive, should contain some numerical data that resulted from analysis of experimental results. And the obtained results and conclusion are not compared with published articles by other researchers. For more contribution, authors should compare their results with those in relevant published works of other researchers. Enhance the depth of your discussions based on the experiment data analysis. Moreover, authors should exhibit the gap in knowledge which the present study fills. Especially, I strongly suggest that this section should be divided into more chapters such as 4.1.1, 4.1.2 and 4.1.3 to improve the quality of this scientific paper.
7. Streamline the conclusions by consolidating the key insights. Emphasize the authors present findings arising from this study, and remove redundant or excessively detailed ‘results’, allowing for a more impactful and succinct summary of the research outcomes.
8. Novelty and field application was not clearly demonstrated in this manuscript.
Comments on the Quality of English LanguageNo comments
Author Response
Please see the detailed response letter in the attachment.
Author Response File: 
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Reviewer 4 Report
Comments and Suggestions for AuthorsIn this manuscript, authors have investigated the foam flooding in tight reservoir conditions with fractional flow theory. Both experimental method and theoretical analysis are introduced to discuss the foam performance with different rock properties, injection methods, and foaming parameters. There are several parts should be polished and more details should be added to improve the quality of the manuscript.
1 Line 87: In this work, authors choose the truncated log-normal distribution instead of commonly used Rayleigh distribution in the pore network generation. Please add more details on this choice.
2 Line 119: Based on the description from Line 123-130, should the situation of multiple lamellae presence within the same pore body or pore throat be excluded, or not? Please further explain the impacts on lamellae distribution during the foam flooding process.
3 Line 123: There are three basic foam generation mechanisms in porous media, including snap-off, leave-behind, and the division. Authors did not mention the last one here in introducing the basic foam generation mode. Please add the relevant discussion, or state it in the assumption of model.
3 Line 305: Two types of reck samples are selected in the experiment section of the manuscript. Both are not as common as classic rock type like Berea core. More detailed mineralogy info or element info should be added.
4 Section 3.2 and Table 3: Foam quality is one of the most important parameters during foam flooding, as well as this work. Could the authors further explain how the foam quality is controlled or maintained, specifically.
5 Figure 16: According to the general assumption of invasion percolation with memory, the immiscible displacement terminates when invading phase reaches the outlet of the porous media. The post-breakthrough displacement continuous by introducing the additional drag effect. However, the end point of simulation results can be extended to the extreme condition when no water flow travelling across the outlet.
Comments on the Quality of English LanguageMinor editing of English language required.
Author Response
Please see the detailed response letter in the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsIt can be accepted at present form.
