Simulation of Oil Well Drilling System Using Distributed–Lumped Modelling Technique

Round 1

Reviewer 1 Report

Journal Modelling (ISSN 2673-3951)

modelling-913534

Article - Simulation of Oil Well Drilling System Using Distributed-Lumped Modelling Technique

Comments to the Author:

The figures: the text inside the figures must have the same pattern (standard) as the main text of the work

Analyze:

Why the Bode Plots evaluations are not included in this study. it will be allowing a model analysis to the frequency domain response

Conclusions:

The conclusions showed are shallow and generic. It should show the modeling influence on practice problems.

for example: “Comparing the applied torque on bit of the two models, as the length of the drill pipe increases the difference between them increases.”     ….   Explain why

Author Response

Article - Simulation of Oil Well Drilling System Using Distributed-Lumped Modelling Technique

On behalf of all the colleagues involved in preparing the paper, I thank your Excellency for your efforts and valuable comments. You are the mirror to clarify and amend the deficiencies of the paper. I wish, for your honorable person, that strenuous efforts were made to prepare the paper, and we tried very hard to implement all your comments.

The figures: the text inside the figures must have the same pattern (standard) as the main text of the work (corrected).

Conclusions:

The conclusion covered all the research content and the aim of the paper.

Author Response File: Author Response.pdf

Reviewer 2 Report

Please find attached a detailed comments.

Comments for author File: Comments.pdf

Author Response

Article - Simulation of Oil Well Drilling System Using Distributed-Lumped Modelling Technique

On behalf of all the colleagues involved in preparing the paper, I thank your Excellency for your efforts and valuable comments. You are the mirror to clarify and amend the deficiencies of the paper. I wish, for your honorable person, that strenuous efforts were made to prepare the paper, and we tried very hard to implement all your comments.

The structure of this manuscript is acceptable, and the sections follow clearly. The conclusions are supported by the data presented. However, the manuscript was prepared very carelessly. Major revisions are suggested. There are some comments from this reviewer that can help the authors to improve the quality of the manuscript. 1. Background (the first 5 sentences) in Abstract is too long. In addition to background, the abstract should contain a description of (i) methods, (ii) main findings, and (iii) conclusions (corrected (

2. Abstract: "WOB". Please define all abbreviations the first time they appear in the abstract and the main text. (corrected)

3. The interpretation of the correctness of the lumped model is very difficult. In many cases, the authors used conflicting designations. According to line 148, Jb has been defined as BHA  inertia. However, according to the line, 112 BHA inertia has been defined as Jd. (corrected)

4. Similar observation to comment 3: in line G is defined as shear modulus, however, according to line 272 G is the shut capacitance, and according to line 271 G is the shut conductance! So, it is very confusing when G in equations 4.8-4.10 mean shut capacitance. (corrected, Clear now in the nomenclature).

There are many conflicts in the notations of parameters. The whole manuscript must be carefully checked. Each parameter must be clearly defined. (corrected)

5. The style (normal or italic) of parameters in the text and in the equations must be unified. One example: compare the notation of parameters G and ρ in lines 179 and 180. (corrected)

6. Due to the many parameters defined in the manuscript, it is suggested to add a nomenclature section. (corrected)

7. Figure 4 should be turned 90° to the left. (The figure related to figure 3, and represents the drilling sequence process which starts from the top to bottom).

8. Figures 7 and 8 must be enlarged because the font size used is too small. (corrected)

9. Lines 364-365: This sentence is not grammatically correct. (corrected)

10. Parameter Kdp from Table 1 has not been defined in the section described the lumped model. (corrected)

11. The graphic quality of Figures 10-21 is extremely poor. The description of the axes and legends are completely illegible. I cannot verify the correctness of the data. The minimum font size in figures should be the same as in the figure caption. (corrected)

12. Are the DL and D-L models the same? (corrected)

12. A list of references is not formatted according to the Instructions for Authors. ((corrected)

14. Table 4: What does "M" mean in the unit of the C1 parameter? (corrected)

15. The whole manuscript: Why is the abbreviation "RPM" written in uppercase? It is also very interesting why are "Lumped", "Applied Torque", …etc. capitalized? (corrected)

Author Response File: Author Response.pdf

Reviewer 3 Report

General Comment

In this manuscript, two modelling approaches to compute the dynamic behavior, namely the stick-slip vibrations at the bottom hole assembly of simple oil well drill systems, are studied. These models are based on a pure lumper model and a distributed lumped (D-L) model. The models are presented with details and their predictions are compared and discussed. In particular, it is concluded that the D-L model approach is more precise when compared with real measurements of stick-slip vibrations.

The topic of the manuscript is interesting and important for practice, since problems related with vibrations in drilling processes are responsible for delays and resistance issues. The models proposed in this manuscript, mainly the D-L model, could be important for the development of simple software packages to help the technical community.

I consider that several parts of the manuscript must be improved. The authors should take the comments into account and revise their manuscript.

Specific Comment 1

The reading of the manuscript is not good. Many sentences are hard to understand and must be rephrased. The authors should seek for professional help to review the text.

Specific Comment 2

Throughout the manuscript, some formatting issues and typos must be corrected.

Also, some references seem to be not cited in the text. For instance [3] and [20]. Please check.

Specific Comment 3

Throughout the manuscript, all acronyms must be defined when they first appear in the text.

Specific Comment 4

Abstract

End statements about the main findings of the manuscript are missing.

Specific Comment 5

References are missing to justify some of the presented equations. For instance, the differential equations of motion Eq. (4.1)-(4.2) were not derived in the manuscript and should be properly referred. Same for other ones.

Specific Comment 6

In most of figures and graphs, the text, symbols or numbers are unreadable. Please improve all figures and graphs with such issue.

Specific Comment 7

Line 225

A reference is missing after “Brawn”.

Specific Comment 8

Page 9

In this page, all the equations and derivations for the torsion of a cylindrical shaft come from the classical theory of elasticity and are well known. For this reason, this part should be deeply summarized and a reference to classical authors should be given.

Specific Comment 9

In the manuscript it is not explained how the models where implemented to obtain the numerical predictions. Please provide such details in the manuscript.

Specific Comment 10

Sections 7.2 to 7.4

The authors claim that the predictions from the models are compared with the real measurements presented in Figure 9. However, in Sections 7.2 to 7.4 it is not clear how this comparison was performed. Graphs from Figures 10 to 21 (namely the graphs presenting the angular velocities versus time), which are very hard to read (refer to previous Comment 6), no experimental data are presented to compare with the curves from the models, nor quantitative analysis is presented in the discussion.

How the real measurements were used to compare with the predictions from the models? Sections 7.2 to 7.4 must be entirely reviewed to clarify this important aspect in order to sustain better the conclusions.

Specific Comment 11

Conclusion

The title should be “Conclusions”.

Also, a final statement about which model is more precise and how it can be used in practice is missing.

Specific Comment 12

Appendix

A confusion seems to exist between the two last sentences before Table 4.

Author Response

Article - Simulation of Oil Well Drilling System Using Distributed-Lumped Modelling Technique

On behalf of all the colleagues involved in preparing the paper, I thank your Excellency for your efforts and valuable comments. You are the mirror to clarify and amend the deficiencies of the paper. I wish, for your honorable person, that strenuous efforts were made to prepare the paper, and we tried very hard to implement all your comments.

Reply to comments - Author 3:

Comments and Suggestions for Authors.

General Comment

In this manuscript, two modeling approaches to compute the dynamic behavior, namely the stick-slip vibrations at the bottom hole assembly of simple oil well drill systems, are studied. These models are based on a pure lumper model and a distributed lumped (D-L) model. The models are presented with details and their predictions are compared and discussed. In particular, it is concluded that the D-L model approach is more precise when compared with real measurements of stick-slip vibrations.

The topic of the manuscript is interesting and important for practice since problems related to vibrations in drilling processes are responsible for delays and resistance issues. The models proposed in this manuscript, mainly the D-L model, could be important for the development of simple software packages to help the technical community. I consider that several parts of the manuscript must be improved. The authors should take the comments into account and revise their manuscript.

Specific Comment 1: The reading of the manuscript is not good. Many sentences are hard to understand and must be rephrased. The authors should seek professional help to review the text. I reviewed it and tried to make it as simple as possible (corrected)

Specific Comment 2: Throughout the manuscript, some formatting issues and typos must be corrected. Also, some references seem to be not cited in the text. (corrected, pages 2 and 23)

Specific Comment 3: Throughout the manuscript, all acronyms must be defined when they first appear in the text. (corrected)

Specific Comment 4: Abstract: End statements about the main findings of the manuscript are missing.  (corrected)

Specific Comment 5: References are missing to justify some of the presented equations. For instance, the differential equations of motion Eq. (4.1)-(4.2) were not derived in the manuscript and should be properly referred to. Same for other ones. (corrected, shown from the paragraph after equation 2).

Specific Comment 6: In most figures and graphs, the text, symbols, or numbers are unreadable. Please improve all figures and graphs with such an issue. (corrected).

Specific Comment 7: Line 225: A reference is missing after “Brawn”. (corrected).

Specific Comment 8: Page 9: On this page, all the equations and derivations for the torsion of a cylindrical shaft come from the classical theory of elasticity and are well known. For this reason, this part should be deeply summarized and a reference to classical authors should be given. (corrected).

Specific Comment 9: In the manuscript, it is not explained how the models were implemented to obtain numerical predictions. Please provide such details in the manuscript. (Perhaps the equations and figures as conclusions contribute to the statement of the purpose of the research study contained in the paper).

Specific Comment 10

Sections 7.2 to 7.4:

The authors claim that the predictions from the models are compared with the real measurements presented in Figure 9. However, in Sections 7.2 to 7.4 it is not clear how this comparison was performed. Graphs from Figures 10 to 21 (namely the graphs presenting the angular velocities versus time), which are very hard to read (refer to previous Comment 6), no experimental data are presented to compare with the curves from the models, nor quantitative analysis is presented in the discussion. How the real measurements were used to compare with the predictions from the models? Sections 7.2 to 7.4 must be entirely reviewed to clarify this important aspect in order to sustain better the conclusions.) With comprehensive adjustments for the entire paper, the comment might be covered(

Specific Comment 11

Conclusion. The title should be “Conclusions”. Also, a final statement about which model is more precise and how it can be used in practice is missing. (corrected)

Specific Comment 12

Appendix. A confusion seems to exist between the two last sentences before Table 4. (corrected)

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

To my comnent:
1. Background (the first 5 sentences) in Abstract is too long. In addition to background, the abstract should contain a description of (i) methods, (ii) main findings, and (iii) conclusions

the Authors replied "corrected".

To my comment:
A list of references is not formatted according to the Instructions for Authors.
the authors also responded "corrected".

etc.

These comment were not incorporated in the manuscript. The authors tried to lie to me.

Modreover, the authors changed the results obtained (Figs. 10-21). This fact has not been explained by authors. So, the mnuscript should be considered as a new submission.

According to publisher requirements "Any revisions should be clearly highlighted, for example using the "Track Changes" function in Microsoft Word, so that they are easily visible to the editors and reviewers." Line numbers must be included in the revised verion of the manuscript.

If the authors do not agree with my comments, they should clearly point this fact.

Author Response

Article - Simulation of Oil Well Drilling System Using Distributed-Lumped Modelling Technique

Reply to comments – Reviewer 2:

Before starting to respond to the comments of your Excellency, I would like to clarify to you that five professors prepared and revised the paper, and three reviewers from the journal, you are one of them. Each of the reviewers has different observations from the other. A reviewer calls for amending all figures and writings under each figure, and the other is amending the introduction and adding another paragraph. Isn’t all of this changing the shape of the paper? I would also like to clarify to you that before sending the reply to you the other authors were informed, and therefore there was no kind of lying or disingenuousness.

Comment-1:

Background (the first 5 sentences) in the Abstract is too long. In addition to background, the abstract should contain a description of (i) methods, (ii) main findings, and (iii) conclusions.

Response from the author

The full text has been added at the end of the abstract and then rewrite the text and revise it linguistically, this is shown in yellow on the origin of the paper. I also reviewed all the texts appearing under the heading "Introduction" and they are presented in yellow (of course, these fundamental amendments change the appearance of the paper and may not be compatible with the other reviewers).

Comment-2:

Define all abbreviations the first time they appear in the abstract and the main text.

Response from the author

All the abbreviations that appeared in the abstract and main text are highlighted in yellow in the paper, and others related to the formulas appear in the nomenclature.

Comment-3:

The interpretation of the correctness of the lumped model is very difficult. In many cases, the authors used conflicting designations. According to line 148, J_b has been defined as BHA inertia. However, according to the line, 112 BHA inertia has been defined as J_d.

Response from the author

, the inertia of the BHA, and this is evident in the core of the paper and in the nomenclature.

Comment-4:

Similar observation to comment 3: inline G is defined as shear modulus, however, according to line 272 G is the shut capacitance, and according to line 271 G is the shut conductance! So, it is very confusing when G in equations 4.8-4.10 mean shut capacitance.

Response from the author

G₀, shear modulus, and G is the conductance, Clear in the nomenclature.

Comment-5:

The style (normal or italic) of parameters in the text and in the equations must be unified. One example: compare the notation of parameters G and ρ in lines 179 and 180.

Response from the author

This was generalized and all fonts were modified to be normal.

Comment-6:

Due to the many parameters defined in the manuscript, it is suggested to add a nomenclature section.

Response from the author

This was added at the end of the paper.

Comment-7

Figure 4 should be turned 90° to the left.

Response from the author

The figure is related to figure 3 and represents the drilling sequence process which starts from the top to bottom, which is agreed upon by all authors.

Comment-8

Figures 7 and 8 must be enlarged because the font size used is too small.

Response from the author

All figures have been re-executed and the fonts enlarged to fit the overall shape of the paper and fulfill your generous suggestion.

Comment-9

Lines 364-365: This sentence is not grammatically correct.

Response from the author

All sentences have been grammatically reviewed and will be returned before finally sent for publication.

Comment-10

Parameter K_dp from Table 1 has not been defined in the section describing the lumped model.

Response from the author

K_dp, the equivalent torsional stiffness of the drillpipe, it appears in yellow on page 5.

Comment-11

There are many conflicts in the notations of parameters. The whole manuscript must be carefully checked. Each parameter must be clearly defined.

Response from the author

All paper has been passed and amended.

Comment-12

The graphic quality of Figures 10-21 is extremely poor. The description of the axes and legends are completely illegible. I cannot verify the correctness of the data. The minimum font size in figures should be the same as in the figure caption.

Response from the author

As I indicated in the response to Comment # 7, all figures have been re-executed and the fonts enlarged to fit the overall shape of the paper and fulfill your generous suggestion.

Comment-13

Are the DL and D-L models the same?

Response from the author

Yes, DL and D-L models are the same, but I scrolled all over the paper and adjusted DL to D-L.

Comment-14

A list of references is not formatted according to the Instructions for Authors.

Response from the author

From the beginning, when preparing the paper, the journal's instructions to the author were taken into account that the form of references should be as follows:

[Author 1, A.B.; Author 2, C.D. Title of the article. Abbreviated Journal Name Year, Volume, page range]

Comment-15

Table 4: What does "M" mean in the unit of the C₁ parameter?

Response from the author

The C_l unit has been modified in Table 4

Comment-16

Why is the abbreviation "RPM" written in uppercase? It is also very interesting why are "Lumped", "Applied Torque", …etc. capitalized?

Response from the author

The abbreviation is composed of capital letters, many writers believe that the full words that define the abbreviation should be capitalized as well. So, when we abbreviate words in a sentence, the abbreviation is capitalized.

Words are capitalized when the abbreviation represents the official name. For example:

Revolution Per Minute (RPM), Distributed Lumped (D-L), Fourier Transform (FT), American Society for Mechanical Engineering (ASME), …etc.

Author Response File: Author Response.docx

Reviewer 3 Report

I received the revised version of the manuscript “Simulation of Oil Well Drilling System Using Distributed- Lumped Modelling Technique”.

The revised version of the manuscript does not highlight the changes made by the authors. All changes in the revised manuscript must be clearly highlighted (for instance with a color) to facilitate the reviewer task. Please highlight all changes.

After reading the authors’ response to my previous comments and after comparing the revised version of the manuscript with the previous one, I realized that most of my previous comments were not properly addressed, or not addressed at all. Namely:

- Previous Specific Comment 1: The reading of the manuscript has not been sufficiently improved. As it was referred in the comment, the authors should seek for professional help.

- Previous Specific Comment 2: Some typos still exist throughout the manuscript. Just one example: in the paragraph right before Figure 3, it should be “…, 3) …” and “…, 4) …” instead of “… . (3) …” and “…, (4) …”, respectively, in order to be uniformized. Other typos exist.

Also, some references are still not properly cited in the text. For instance, in page 1 reference [4] is cited after references [1,2]. References must be cited in order and [3] is missing. Please refer to the “Instructions for Authors”.

- Previous Specific Comment 4: This comment was not addressed! No end statements about the main findings of the manuscript were added in the abstract.

- Previous Specific Comment 5: This comment was not addressed! No references ([?]) were added in the text to justify the referred equations.

- Previous Specific Comment 7: This comment was not addressed! A reference ([?]) is still missing after “Brawn”.

- Previous Specific Comment 8: This comment was not properly addressed! The referred part of the manuscript was basically maintained unchanged.

- Previous Specific Comment 9: This comment was not properly addressed! I didn´t found in the revised manuscript an explanation about how the models where implemented in the computer to obtain the numerical predictions.

- Previous Specific Comment 10: The authors must properly reply the reviewer’s comment and explain how the referred important concern was addressed in the revised manuscript.

- Previous Specific Comment 11: This comment was not addressed! The title should be “Conclusions” and not “Conclusion”. In addition, the required final statement about which model is more precise and how it can be used in practice was not added.

- Previous Specific Comment 12: This comment was not addressed! The referred sentences remained basically unchanged.

From the above, I consider that the manuscript has not be sufficiently improved to be accepted for publication and still needs a major revision.

Author Response

Article - Simulation of Oil Well Drilling System Using Distributed-Lumped Modelling Technique

General Comment from reviewer-3

After reading the authors’ response to my previous comments and after comparing the revised version of the manuscript with the previous one, I realized that most of my previous comments were not properly addressed, or not addressed at all. Namely:

The general response to comments and before detailing each comment separately:

Before starting to respond to the comments of your excellency, I would like to clarify to you that five professors prepared and revised the paper, and three reviewers from the journal, you are one of them. Each of the reviewers has different observations from the other. A reviewer calls for amending all figures and writings under each figure, and the other is amending the introduction and adding another paragraph. Isn’t all of this changing the shape of the paper? I would also like to clarify to you that before sending the reply to you the other authors were informed, and therefore there is no kind of negligence to respond to your comments, but rather we try to bridge the gap between the authors and the reviewers.

Comment-1:

The reading of the manuscript has not been sufficiently improved. As it was referred to in the comment, the authors should seek professional help.

Response from the author

All texts have been linguistically revised with modification in the abstract, introduction, and conclusion, and this is evident in the red color in the modified paper.

Comment-2:

Throughout the manuscript, some formatting issues and typos must be corrected. Also, some references seem to be not cited in the text.

Some typos still exist throughout the manuscript. Just one example: in the paragraph right before Figure 3, it should be “…, 3) …” and “…, 4) …” instead of “… . (3) …” and “…,

Response from the author

The general instructions of the author were taken from the journal, that the reference to the figure should be as follows: [Figure][Number][Point]. But the amendment was based on your guidance.

The entire paper was reviewed and it was confirmed that all references [1-31] were cited, this is shown in red.

Comment-3:

Throughout the manuscript, all acronyms must be defined when they first appear in the text.

Response from the author

All acronyms have been reviewed and corrected.

Comment-4:

Abstract: End statements about the main findings of the manuscript are missing. This comment was not addressed! No end statements about the main findings of the manuscript were added in the abstract.

Response from the author

A statement (The D-L model is more precise, particularly for long strings. Using the simulations, the most comprehensive modeling methodology was introduced) was added in the last part of the abstract, and then all the abstract was reviewed. This is shown in red color.

Comment-5:

References are missing to justify some of the presented equations. For instance, the differential equations of motion Equations 1) and 2) were not derived in the manuscript and should be properly referred to. Same for other ones.

Response from the author

In any research, the equations are either extracted or referred to for previous research. In this paper, some equations refer to the source for them, such as equation (7) and reference 22-24. The text preceding equations 1) and 2) explains the equations and how to construct them based on the general equation of motion, which can be expressed as:

These equations and post-publication can be a reference for many researchers.

Comment-6:

In most figures and graphs, the text, symbols, or numbers are unreadable. Please improve all figures and graphs with such an issue.

Response from the author

Figures have been re-executed and the writings clarified for each Figure.

Comment-7:

A reference is missing after “Brawn”. (corrected).

Response from the author

This has been corrected, as it appears on page 7, in red. Whereas, Brown is the reference number [18], page 7.

Comment-8:

Page 9: On this page, all the equations and derivations for the torsion of a cylindrical shaft come from the classical theory of elasticity and are well known. For this reason, this part should be deeply summarized and a reference to classical authors should be given.

Response from the author

This is summarized and noted in Equations 8( and 9).

Comment-9:

In the manuscript, it is not explained how the models were implemented to obtain numerical predictions. Please provide such details in the manuscript.

Response from the author

That's right, we forgot to add this detail. To that end, the paragraph has been added under the results and analysis heading, page 12, and this is visible in the yellow color.

Comment-10:

The authors claim that the predictions from the models are compared with the real measurements presented in Figure 9.

However, in Sections 7.2 to 7.4, it is not clear how this comparison was performed. Graphs from Figures 10 to 21 (namely the graphs presenting the angular velocities versus time), which are very hard to read (refer to previous Comment 6), no experimental data are presented to compare with the curves from the models, nor quantitative analysis is presented in the discussion. How the real measurements were used to compare with the predictions from the models? Sections 7.2 to 7.4 must be entirely reviewed to clarify this important aspect to sustain better the conclusions

Response from the author

Corrected the position of figure 9), under section-7 (results and analysis).

• 2 Simulation for drill pipe length of 2000 meters, the simulations were performed at 2000 m in length using the variable parameters in Table 1. This included Figures 10-15.
• 3 Simulation for drill pipe length of 5700 meters, the simulations were performed at 2000 m in length using the variable parameters in Table 2 This included Figures 16-19.
• 4 Simulation for drill pipe length of 7500 meters the simulations were performed at 2000 m in length using the variable parameters in Table 3. This included Figures 20-21.

Through the figures and what the explanations contained, the reader can explain, understand, and distinguish each part.

Comment-11:

Conclusion. The title should be “Conclusions”. Also, a final statement about which model is more precise and how it can be used in practice is missing.

Response from the author

The title of the Conclusion was corrected to “Conclusions”.

The final statement about which model is more precise and how it can be used in practice is obvious in the first paragraph, starting from the fourth line. This is indicated in the yellow color, page 20.

Comment-12:

Appendix. The confusion seems to exist between the two last sentences before Table 4.

Response from the author

The text, which was before the appendix, was moved to the end of the conclusions, then referred to in Table 4. This is indicated in the yellow color, page 21.

Author Response File: Author Response.docx