Optimization of the Configuration of the Power Sections of Special Small-Sized Positive Displacement Motors for Deep-Penetrating Perforation Using the Technical System “Perfobore”

Round 1

Reviewer 1 Report

Ladies and Gentlemen, Here are my comments on the article
Optimization of the configuration of the power sections of spe-2 cial small-sized positive displacement motors for deep-pene-3 trating perforation using the technical system "Perfobore" The article describes the layout of a “tailor made” downhole motor for a specific application. There was no suitable motor available on the market place. The approach for the calculations sometimes appear a bit uncommon – although they are not wrong. And also the presentations of the results (and the English) could certainly be improved. In some diagrams there are no axes – which makes them difficult to understand. However, in the end a practical design is made, a prototype tool is built and tests are run successfully. I think that the overall story could be interesting for many readers. However I would recommend to rework the article a bit (add axes to the graphs, have the English reviewed by a native speaker and improve the chapter “Results” by reducing the amount of numbers in the text and replacing them by some tables or graphs instead. All this would make the article easier to read and understand. The overall project is interesting and “new”.

Author Response

Dear reviewer, thank you for feedback.
First of all, we changed the Figure 5 and added axes for the Figures  7 and 8.
Secondly, we reformulated the chapter “Results” and added summarize Table 5. This Table include the results of comparative analysis of the technical indicators of PSs, which were presented as a text  before. Finally we used help professional interpreter to improve English language and style. 

Dear reviewer, thank you for feedback.
First of all, we changed the Figure 5 and added axes for the Figures  7 and 8.
Secondly, we reformulated the chapter “Results” and added summarize Table 5. This Table include the results of comparative analysis of the technical indicators of PSs, which were presented as a text  before.Finally we used help professional interpreter to improve English language and style. 

 

Reviewer 2 Report

A brief summary 

The article describes the technical system "Perfobore" that is intended for the construction of a network of 29 branched channels of the small diameter and curvature radius along the predicted trajectory to overcome the contaminated section of the pay zone or increase the efficiency of the development of old and marginal hydrocarbon reservoirs. The implementation of this technology became possible with the use of specially designed small-sized equipment, for example, the bore bit diameter is from 58 to 75 mm and the diameters of the housing elements of the positive displacement motors (PDM) are from 43 to 55 mm.

Broad comments 

1. Introduction is too short with only 4 references, and 3 of them are self-citations. It is necessary to list the technologies currently applied for the exploitation of marginal hydrocarbon reservoirs. It should be made clear whether “Perfobore” is used for drilling or just for perforation as the title suggests (“…for deep-penetrating perforation...“?
2. Which drilling fluid is used during drilling of a network of branched channels of the small diameter? The composition and properties of the drilling fluid are lacking. Flow rate is 1-2 l/s (Table 1).
3. The limitations of this technology need to be addressed.
4. Conclusions should be reformulated in such a way as to clearly highlight the results of the research without general formulations.

Specific comments 

1. Line 20: write „in the diametres of 43 to 55 mm“ instead of „in the 43 ... 54 mm 21 size“
2. Line 22: write „field tests (FT) from 2018 to 2020” instead of “field tests (FT) in 2018 ... 2020.“
3. Lines 32-33: write „the diameters of the housing elements (body diameter, D_b) of the positive displacement motors 33 (PDM) are from 43 to 55 mm. It is necessary to add to the sentence "Body diameter, D_b" because this term is used in Tables 1 and 2 and in the rest of the text.
4. Lines 49, 52, 66, 75, 92 and 261: use term „rotation moment“ instead of „rotative moment“
5. Lines 65/66: write „while drilling using the D-429/10 PDM“ instead of „while drilling the D-429/10 PDM“
6. Lines 77-80: write „.... are presented in the ref. [7].... „ instead of „.... are presented in the article [Lyagov, I.A., Baldenko, F.D., Lyagov, A.V., Yamaliev, V.U., Lyagova, A.А. Methodology for calculating technical efficiency of power sections in small-sized screw downhole motors for the «Perfobur» system. Journal of Mining Institute 2019), 240, pp. 694-700. DOI: 10.31897/PMI.2019.6.694. The cited article should be added to the References as reference number [7].... before Dvoynikov (Page  12).
7. Table 4, row 25: “Skewing moment “or “Bending moment”?

Author Response

Dear reviewer, thank you for feedback.The answers on your comments are presented in attachment.

Please see the attachment

 

 

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I accept the answers. Please, attach revised version of the manuscript with inserted new text and errors corrected. The available versions (v1 and v2) are identical!

Author Response

Dear Sir or Madam, 

Thank you for your response. I would like to upload a new version of paper both  in. doc and also in .pdf formats

Author Response File: Author Response.docx