Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study of water injection resistance in homogeneous and heterogeneous cores is both interesting and meaningful. A large number of experiments demonstrate the differences between the two, providing convincing evidence and conclusions with practical value. I recommend the paper for publication.

Issues with the paper:

    1.Make sure that terms like “Plugging/blockage” or “microparticle migration/fine migration” are used consistently throughout the paper. Switching between terms can confuse readers.

    2.In the title “Plugging Resistance and Plugging Position,” the word “Plugging” is repeated twice. It is recommended to keep only one.

    3.In the abstract, the novelty of the study needs to be clearly highlighted. It is recommended to provide a detailed description of the uniqueness of the experimental method.

    4.In the abstract, the concluding statement should include implications for field operations or future work to add more depth.

    5.The sentence, “The study provides theoretical support for analyzing the blockage locations and pressures in loose sandstone water injection and offers a theoretical basis for selecting the direction of acidizing to remove blockages after they occur in loose sandstone,” needs to be improved.

    6.In the introduction, include more references to literature on plugging to transition smoothly to the research method.

    7.In line 102 of the introduction, “Therefore, this paper establishes a parallel simulation experiment with reservoirs of different permeability,” the wording seems vague. The “simulation” here may refer to an experiment capable of mimicking conditions in real reservoirs.

    8.The section “2.1. Mechanism of Fine Particles and Suspended Solids Blockage” should be placed in the introduction.

    9.In section “2.2. Micromorphology Analysis of Blockages,” it’s unclear how these blockages were obtained. Please explain.

    10.The section “2.3. Physical Experimental Simulation Methods for Blockage Location and Blockage Resistance Due to Fine Particles and Suspended Solids” should follow the sample preparation section.

    11.“2.4. Fluids and Preparation of Experimental Samples” should be revised to “2.4. Fluids and Samples Preparation,” and this section should be placed earlier (before section 2.1).

12.In the conclusion, more emphasis should be placed on the differences between homogeneous and heterogeneous cores.

By optimizing these aspects, the paper will become more persuasive and logical, allowing readers to better understand the research content and its practical application value.

Comments on the Quality of English Language

Nice

Author Response

 

Comments 1: Make sure that terms like “Plugging/blockage” or “microparticle migration/fine migration” are used consistently throughout the paper. Switching between terms can confuse readers.

Response 1: Thank you for pointing this out. We agree with this comment. Therefor, We consistently use " blockage " or " microparticle migration " throughout the paper.

 

Comments 2: In the title “Plugging Resistance and Plugging Position,” the word “Plugging” is repeated twice. It is recommended to keep only one.

Response 2: Thank you for pointing this out. We agree with this comment. Therefor, We have revised the title to “Experimental Evaluation of Plugging Resistance and Position Caused by Microparticle Migration in Water Injection Wells”.

 

Comments 3: In the abstract, the novelty of the study needs to be clearly highlighted. It is recommended to provide a detailed description of the uniqueness of the experimental method.

Response 3: Thank you for pointing this out. We agree with this comment. We have changed the innovative aspects of the experiment in the abstract to: This paper establishes a simulation experiment for water injection blockage that can accommodate both homogeneous and heterogeneous cores. The experimental core is 1 meter long, capable of simulating the blockage conditions in the near-well zone during water injection, thereby analyzing the core blockage position and blockage pressure. See the red text in lines 20-22 of the abstract.

 

Comments 4: In the abstract, the concluding statement should include implications for field operations or future work to add more depth.

Response 4:Thank you for your suggestion. In the last part of the abstract, we have revised it to: This study provides theoretical support for the analysis of blockage locations and pressures in loose sandstone water injection, and offers technical support for the design of unplugging ranges and pressures after blockage in heterogeneous formations. At the same time, it provides a theoretical basis for selecting the direction of acidizing after blockage occurs in loose sandstone. See the red text in the last part of the abstract.

 

Comments 5: The sentence, “The study provides theoretical support for analyzing the blockage locations and pressures in loose sandstone water injection and offers a theoretical basis for selecting the direction of acidizing to remove blockages after they occur in loose sandstone,” needs to be improved.

Response 5:The revisions have been made and are consistent with the changes for Response 4.

 

Comments 6: In the introduction, include more references to literature on plugging to transition smoothly to the research method.

Response 6:Thank you for pointing this out. We agree with this comment. In the introduction section, we will add literature on the impact of particle migration on blockage, modified as follows: Microparticles migrating in rock pores and fractures are influenced by various factors [26-27]. In recent years, scholars have conducted extensive theoretical and experimental research to study the migration patterns of microparticles in these fractures. Based on a self-developed experimental device for evaluating microparticle migration and sedimentation, different fluid conditions (fluid salinity and flow rate) were set up for displacing experiments [28]. The research found that microparticle migration and blockage in the near-well fractures are significant factors contributing to blockage, with microparticles severely damaging permeability and flow capacity, and the damage degree increasing sharply with higher microparticle concentration [29-30]. However, the process of microparticle migration causing blockage in reservoirs remains a "black box," and the suspension and sedimentation patterns of microparticles in the pores are still unknown.

 

Comments 7: In line 102 of the introduction, “Therefore, this paper establishes a parallel simulation experiment with reservoirs of different permeability,” the wording seems vague. The “simulation” here may refer to an experiment capable of mimicking conditions in real reservoirs.

Response 7:Thank you for pointing this out. We agree with this comment. This part has been revised to: This paper establishes a simulation experiment for water injection blockage that can accommodate both homogeneous and heterogeneous cores. The experimental core is 1 meter long, capable of simulating the blockage conditions in the near-well zone during water injection.

 

Comments 8:.The section “2.1. Mechanism of Fine Particles and Suspended Solids Blockage” should be placed in the introduction.

Response 8: Thank you for pointing this out. The description of the mechanisms in this section mainly focuses on the migration and aggregation of microparticles that lead to the formation of blockages. Therefore, it is recommended to place it in subsection 2.1.

 

Comments 9: In section “2.2. Micromorphology Analysis of Blockages,” it’s unclear how these blockages were obtained. Please explain.

Response 9: Thank you for pointing this out. In section “2.2. Micromorphology Analysis of Blockages,” we have made revisions and additions. Using the FEI Quanta250 SEM field emission scanning electron microscope, we observed the blockage materials in the core during the experiment. The resolution of the secondary electron images reached 1.04 nm, with a magnification range of 15 to 300,000 times, allowing for thin section analysis of the blockages.

 

Comments 10: The section “2.3. Physical Experimental Simulation Methods for Blockage Location and Blockage Resistance Due to Fine Particles and Suspended Solids” should follow the sample preparation section.

Response 10: Thank you for pointing this out. We agree with this comment. We have made adjustments and changed “2.3. Physical Experimental Simulation Methods for Blockage Location and Blockage Resistance Due to Fine Particles and Suspended Solids” to 2.2. Other subsections have been adjusted accordingly.

 

Comments 11: “2.4. Fluids and Preparation of Experimental Samples” should be revised to “2.4. Fluids and Samples Preparation,” and this section should be placed earlier (before section 2.1).

Response 11:Thank you for pointing this out. We agree with this comment. We have adjusted section 2.4 to section 2.2, and other subsections have been adjusted accordingly.

 

Comments 12: In the conclusion, more emphasis should be placed on the differences between homogeneous and heterogeneous cores.

Response 12:Thank you for pointing this out. We agree with this comment. The conclusion section has been revised to: Compared to homogeneous cores, heterogeneous cores experience more severe blockage in the near-well zone. Experimental results show that it requires twice the unplugging pressure to address the blockage pressure in the near-well zone. See the red text in the last part of the conclusion.

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In the review of the manuscript titled Experimental Evaluation of Plugging Resistance and Plugging Position Caused by Microparticle Migration in Water Injection Wells. The authors have provided a good description and the methodology is also fine. I would like to see this article publish but after some questions as follow;

1.      What are the main factors contributing to water injection blockage in offshore oil field loose sandstone reservoirs as identified in the study?

2.      How does the paper simulate the heterogeneity of reservoir cores in its experiments, and why is this simulation important?

3.      What techniques were used to characterize the reservoir blockage samples, and what did these techniques reveal about the composition of the blockages?

4.      How does the length of the core affect the blockage characteristics during water injection according to the study?

5.      What were the primary components of the fine particles causing blockage, as identified through SEM and XRD analysis?

6.      In terms of pressure and permeability changes, how does reservoir heterogeneity impact water injection capacity in core flooding experiments?

7.      According to the study, what is the effect of initial permeability at the inlet on the final blockage resistance in heterogeneous reservoirs compared to homogeneous ones?

8.      What is the ratio of blockage locations and lengths in heterogeneous cores compared to homogeneous cores?

9.      How does the study propose using its findings to address blockage issues in loose sandstone reservoirs?

10.  What theoretical support does the paper provide for selecting the direction of acidizing to remove blockages in loose sandstone reservoirs?

 

 

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

 

The authors in the present manuscript show that this paper establishes a parallel simulation experiment with reservoirs of different permeability, each 1 meter in length, to simulate the heterogeneity of reservoir cores and investigate the effect of core length on the reservoir blockage characteristics during water injection. The study clarifies the influence of water quality indicators, heterogeneity, and core length on the blockage patterns in reservoirs during water injection. The research findings are as follows: I. The reservoir blockage samples were characterized using scanning electron microscopy (SEM), casting thin sections, and X-ray diffraction (XRD) analysis. The results indicate that the main factors causing blockage are clay, silt, and fine particulate suspensions, with the fine particles mainly consisting of hydrated silicates and alkali metal oxides. The primary cause of blockage in loose sandstone is identified as the mechanism of migration and accumulation of clay, fine rock particles, and suspended matter in the injected water. II. By monitoring pressure and permeability changes in the core flooding experiments, the impact of reservoir heterogeneity on water injection capacity was evaluated. The evaluation results show that the blockage locations and lengths in heterogeneous cores are twice those 33 in homogeneous cores. III. The authors should address the following issues and information’s before publication acceptance in the prestigious ‘Processes’ Journal:

1. In the Introduction, authors should add a Table that compares the core length, simulated and parallel simulation experiment with reservoirs parameters with the reported papers.

2. Can authors explain in detail what are the research gap and novelty of this study?

3. In Figure 3, authors should support the XRD peaks values with literature?

4. In Table 1, how do authors measure the ion analysis of injection water?

5. In Figure 7, why shows lower blockage pressure in homogeneous core at 20 ml/min for DE segment permeability?

6. Authors should add the Characterization section in detail to incorporate the XRD, SEM and other instrument information? Authors may go through these two publications for more details and cite accordingly: https://doi.org/10.1016/j.matchemphys.2019.122102 & https://doi.org/10.1016/j.carbon.2024.119331

 

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Minor editing of English language required.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

This paper is concerned with investigating the problems of blockage and permeability decline of reservoirs especially loose sandstone reservoirs during the water injection process, resulting in an increase in injection pressure, preventing further in situ water injection. In this paper, a parallel simulation experiment was conducted with reservoirs of different permeability , monitoring parameters such as flow rate and permeability changes in parallel cores to simulate the heterogeneity of reservoir cores and to investigate the effect of core length on reservoir blockage characteristics, blockage location, its resistance during water injection. The study clarifies the effects of water quality indices, heterogeneity and core length on reservoir blockage patterns during water injection

 

The work is interesting and publishable with the following additions:

 

1. Page 6 : In order to make the simulation model easier to understand, especially for younger readers, with formula (1), we propose to introduce the definition of the physical quantity ki - ‘permeability’ and its units in which it is given in the formula. Please supplement

2. Figures 7, 8, 9, 10, 11 and 12: the descriptions on the graphs of the individual lines are too small and thus unreadable. In order to increase the readability of the graphs, please enlarge the above descriptions on the graphs. Please supplement.

3. In the experiment presented, deposits with homogeneous and heterogeneous cores were analyzed. It seems that the experiment neglected the influence of the physical properties of the clay - which often accompanies the process of flooding the deposit (for example, clay swelling phenomena") - on the blocking process. Please comment.

4 Experimental veryfication. There is no specification of sensor (pressure, flow) types and their accuracy or discussion of measurement errors. Please supplement

5. Of the 29 items quoted in references, only 7 items are from outside Asia. Please add a few items from the USA and Europe. Please supplement

Author Response

Please see the attachment.

Author Response File: Author Response.pdf