Experimental Study on Enhanced Oil Recovery of the Heterogeneous System after Polymer Flooding
Round 1
Reviewer 1 Report
1. In section 2.1, kindly illustrate the unit of M.Wt.
2. The language needs to be revised.
3. Kindly estimate the adsorbed layer thickness of the polymer slug.
4. Provide relative permeability curves at different saturations.
Moderate editing of English language required
Author Response
Thank you very much for your advice. According to your suggestion, we have completed all the modifications. And we sincerely hope that the reviewers are satisfied with our answers.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
This study is devoted to the combination of preformed particle gel with the 30% hydrolyzed polyacrylamide polymer to achieve a heterogenous system, which can improve the sweep efficiency of the heterogenous reservoir formations by increasing the viscosity of the polymers and blocking highly permeable formations by PPG particles. Thus, the oil recovery factor can be improved by the proposed technology. In this regard, the topic is relevant and the authors carried out many experiments to support their expectation. Although the manuscript draft is structured and the most data are well presented, there are some recommendations for authors to better the quality of the manuscript:
1. The authors have to review some more relevant literatures on the modification of the flooding polymer compositions
2. The mechanism of polymer and PPG interaction is not discussed at all, as well as how to achieve the heterogenous system. Please, provide further detail.
3. Figure 3: the shear rate of the measured viscosity values must be provided. In addition to the obtained results, the main reason of the viscosity reduction by time should be discussed. It is recommended for authors to evaluate the size of the PPG after every 5 days of dispersion in the polymer medium and corelate with the results of the viscosity measurement. Did the authors visually notice any precipitation after 5 days and further?
4. Please, shortly discuss the role of epoxy resin and ethylenediamine and provide average porosity values for artificial core samples along their permeability values
5. Did the authors evaluate the influence of the injection rate to the sweep efficiency? Why 0.3 mL/min?
6. The conclusion must be short and the results must be provided in numbers
In addition to the main concerns, there are many organizational and grammatical problems, for example:
Lines 9-13, 65-67, 70-71: grammatical construction issues. Avoid «Daqing oil field has created….»; «….developed by Daqing….» «…particle gel was created by Daqing Oilfield……».
Line 36: use generally accepted term «residual oil» instead «leftover oil»
Line 42: circulation of what? What the authors mean by «……output and replacement have dropped»?
Lines 53-55: the past form must be applied for this sentence. Just after this sentence, the challenges of the applied weak-alkali terpolymer flooding must be discussed at least by couple of the sentences.
Lines 56-59: the term «weak gel» must be defined before the first use. «…in-field tests»?
Lines 13 and 63: define PPG, B-PPG and HPAM abbreviations
Lines 83-86: «the correlation properties»? «…the application of heterogeneous flooding fields»? the last sentence must be reconsidered.
All the discussion of the figures must be done before presenting the corresponding figures.
The used term «permeability range» throughout the text must be checked and replaced, as it does not reflect the intend of the authors
The manuscript can be published after a major revision.
already mentioned in the main review report
Author Response
Thank you very much for your advice. According to your suggestion, we have completed all the modifications. And we sincerely hope that the reviewers are satisfied with our answers.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments for author File: Comments.pdf
Author Response
Thank you very much for your advice. According to your suggestion, we have completed all the modifications. And we sincerely hope that the reviewers are satisfied with our answers.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Accepted
Reviewer 2 Report
The manuscript draft was significqantly revised by the authors and the quality of the manuscript was improved. The manuscript is now can be accepted in the present form.
