Exploring the Spatial Variations of Stressors Impacting Platform Removal in the Northern Gulf of Mexico
Round 1
Reviewer 1 Report
Dear authors:
Your research “Exploring the Spatial Variations of Stressors Impacting Plat-2 form Removal in the Northern Gulf of Mexico” is interesting, relevant and a good fit for JMSE. I have some questions and comments.
Where was the data for slot drill count, Category 5 hurricane (C5) yearly, 390 maximum reported wind gust (MRWG), salinity, phosphorus obtained from. I did not see it included in the data description section. The name of the source or database, historical period, resolution and other elements of description would be important. Representing these values in a map would be relevant to compare with Figure 4.
Texas has significantly larger jurisdiction over coastal areas than other states. How is this affect the research? It is relevant to discuss if some of the platforms outside Federal waters (in Texas) may have relevant effects on the outcome of the study.
The figure description on several figures are displaced (several rows below the figure)
The conclusion should include future research, and limitations on the research
In the keyword section there is a segment of the template that was not deleted.
Author Response
Reviewer 1,
We would like to thank you for taking the time to provide feedback on our manuscript. Our responses to the constructive comments are detailed below. We found all of them incredibly helpful and believe the paper is better because of them. Our responses are in red below and all corresponding changes in the manuscript have been noted by line number and highlighted in red.
Reviewer 1
Your research “Exploring the Spatial Variations of Stressors Impacting Plat-2 form Removal in the Northern Gulf of Mexico” is interesting, relevant and a good fit for JMSE. I have some questions and comments.
We sincerely appreciate the time that the reviewer took to make comments and suggestions on the manuscript. They were constructure and very useful in helping us craft a better manuscript.
1. Where was the data for slot drill count, Category 5 hurricane (C5) yearly, 390 maximum reported wind gust (MRWG), salinity, phosphorus obtained from. I did not see it included in the data description section. The name of the source or database, historical period, resolution and other elements of description would be important. Representing these values in a map would be relevant to compare with Figure 4.
This is a very good point – we added more descriptive text in section 3.1 and additional metadata on the sources of these attributes are available in Appendix A Table 1.
2. Texas has significantly larger jurisdiction over coastal areas than other states. How is this affect the research? It is relevant to discuss if some of the platforms outside Federal waters (in Texas) may have relevant effects on the outcome of the study.
As shown in Figure 1 the spatial scope of this study was limited to Federal waters therefore, we only applied platforms records that fell within the Federal water boundary. We agree that if we included platforms from state waters, especially those along the Texas coast, the outcomes of this study, and which variables were selected might change given proximity to shore, older platforms tending to be more nearshore, shallower water depths, different production levels, etc.
3. The figure description on several figures are displaced (several rows below the figure)
Thank you, we went through and rectified the displaced figure descriptions.
4. The conclusion should include future research, and limitations on the research
We agree and have added text on future research and limitations in the conclusions section.
5. In the keyword section there is a segment of the template that was not deleted.
Thank you for catching this. It has been removed.
Reviewer 2 Report
Firstly, congratulations on the interesting article with very appealing analysis and "intriguing" results but also interesting results. The article enables an organized broad overview of platforms' reliability and lifetime period, based on quantifiable factors/variables analysed with descriptive statistical techniques, which is not that common in the literature. A problem with such approaches is that they often neglect design and other technical or environmental aspects that have an influence in the lifetime analysis and that are not captured in the final results provided. This becomes quite evident in L505 concerning the correlation with water depth which was quite intriguing as the authors say. Anyway, despite that fact, the article does give interesting outcomes, which in provided a good view of the current situation in GoM. The article's approach could be applied, in future, to other growing marine energy sectors, including renewable energy and to many other locations throughout the world. This is of added value but it is not highlighted enough in the intro and the conclusions. With some additions and brief clarifications, the publication of this article is recommended.
Minor revisions are given below.
L11 is lacking
L15 diverse variety is redundant
Keywords - remove the instructions sentence
L27-31 - the repowering of these platforms and reconversion into further renewable energy structures, e.g. for offshore wind, is also become quite trending in terms of novel research. Please include a note on this. Eventually, near reference 4 you may consider to add the following refs (part 1 and 2) which compile numerous failure cases in oil rigs and oil platforms including consequences assessment and address prospective guidelines for offshore renewable energy applications to currently existing platforms. REF 1 doi: 10.1680/jmaen.2019.172.4.118 REF 2 doi: 10.1680/jmaen.2020.173.4.96 (These could also or alternatively be cited in L201 - section Incidents).
Question - the data base that you used is freely available? so this could made clear at the beginning of the paper for the benefit of the reader and for him to know where he can look for it.
L46 near REF 10, this ref could be and interesting one to cite here as it points out norms on jackets design and how it can be of great importance to consider new design consideration in such norms, in this case for fatigue doi: 10.1680/jmaen.2019.24
L64 - I am not sure if disparate is the word you are looking for here.
L72 - instead of conversations I would use industry-government interactions and decision making.
Correction - section 1. only has 1.1, there is no 1.2. So the 4th level titles can become second level ones and 1.1 should be 1, I guess. Adjust the titles numbering.
L105 - there is also benefit from your publication in terms potential incidents for novel fields of offshore engineering research which do not have as much data as the oil and gas sector, namely, in terms of wave energy, offshore wind foundations etc... Please highlight this at L105 or in the Conclusions section.
S1.1.1. Is this section is too small can this be joint to the next version?
L124 - who found that? is there a reference?
L154 - a comment should be given to the uncertainty caused by Climate change as well. Most structures have been designed without any consideration on potential uncertainty and increased variability of extreme phenomena caused by climate change.
Comment - not mandatory - in section 1.1.1.2 or 1.1.1.3 some references could be given on oil spills caused by such events and conditions as the ones you are describing, as this as a huge impact on local habitats, fauna and flora. An example here: DOI 10.5894/rgci-n65
Comment - Sincere congratulations to the authors for the large and interesting data base analysed and described in section 2. It can be of great importance to further studies.
L348 - environmental data?
Question - interesting SVD and PCA analysis were applied to reduce the set of variables to the most relevant ones. However, a note should be included for the benefit of the reader that this does not ensure that other important values might be left aside since there is a reduction to a smaller set given by this analysis.
Fig 3 - what does the colour scale stands for?
Comment - sometimes in these type of analysis if the order of magnitude of different values is different, say for example MRWG in comparison to C5, may have an influence on the % information explained by different vectors. Thus often a standardirization of all variables is applied. Have you considered this?
L505 - 509 - This surely has something to do with design situations. Larger water depths can be related to larger wave heights and thus further loading and fatigue problems. On the other side small water depths may correlate for example with breaking waves at the platforms which may decrease the lifetime of the platform...This should be clarified a bit better, by looking to at least some examples in the data base that lead to this intriguing relationship behaviour.
Fig. 5 caption seems to be away from the page...please place it in the proper place.
L610 - or benefit from the similar analysis applied to smaller sets of variables related to specific design aspects and components of lifetime integrity reduction?
L612-614 - ok that is fine, but at least partially your analysis has numerous applications to marine renewable energy applications including offshore wind and so on. This aspects needs to be highlighted here.
Author Response
Reviewer 2,
We would like to thank you for taking the time to provide feedback on our manuscript. Our responses to the constructive comments are detailed below. We found all of them incredibly helpful and believe the paper is better because of them. Our responses are in red below and all corresponding changes in the manuscript have been noted by line number and highlighted in red.
Reviewer 2
Firstly, congratulations on the interesting article with very appealing analysis and "intriguing" results but also interesting results. The article enables an organized broad overview of platforms' reliability and lifetime period, based on quantifiable factors/variables analysed with descriptive statistical techniques, which is not that common in the literature. A problem with such approaches is that they often neglect design and other technical or environmental aspects that have an influence in the lifetime analysis and that are not captured in the final results provided. This becomes quite evident in L505 concerning the correlation with water depth which was quite intriguing as the authors say. Anyway, despite that fact, the article does give interesting outcomes, which in provided a good view of the current situation in GoM. The article's approach could be applied, in future, to other growing marine energy sectors, including renewable energy and to many other locations throughout the world. This is of added value but it is not highlighted enough in the intro and the conclusions. With some additions and brief clarifications, the publication of this article is recommended.
We sincerely appreciate the time that the reviewer took to make comments and suggestions on the manuscript. They were constructive and very useful in helping us craft a better manuscript.
Minor revisions are given below.
1. L11 is lacking
We are unable to respond to this comment because we are not sure what the reviewer is referring to.
2. L15 diverse variety is redundant
Changed to “diverse set”.
3. Keywords - remove the instructions sentence
Thank you for catching this. It has been removed.
4. L27-31 - the repowering of these platforms and reconversion into further renewable energy structures, e.g. for offshore wind, is also become quite trending in terms of novel research. Please include a note on this. Eventually, near reference 4 you may consider to add the following refs (part 1 and 2) which compile numerous failure cases in oil rigs and oil platforms including consequences assessment and address prospective guidelines for offshore renewable energy applications to currently existing platforms. REF 1 doi: 10.1680/jmaen.2019.172.4.118 REF 2 doi: 10.1680/jmaen.2020.173.4.96 (These could also or alternatively be cited in L201 - section Incidents).
These are great suggestions. We have modified the introduction to include the references and research notes.
5. Question - the data base that you used is freely available? so this could made clear at the beginning of the paper for the benefit of the reader and for him to know where he can look for it.
This information is available at the end in a standard JMSE format under the data availability statement.
6. L46 near REF 10, this ref could be and interesting one to cite here as it points out norms on jackets design and how it can be of great importance to consider new design consideration in such norms, in this case for fatigue doi: 10.1680/jmaen.2019.24
This is a very relevant reference. We have added it.
7. L64 - I am not sure if disparate is the word you are looking for here.
This term has been removed.
8. L72 - instead of conversations I would use industry-government interactions and decision making.
This is a good suggestion; we have changed the wording.
9. Correction - section 1. only has 1.1, there is no 1.2. So the 4th level titles can become second level ones and 1.1 should be 1, I guess. Adjust the titles numbering.
The section numbering has been corrected.
10. L105 - there is also benefit from your publication in terms potential incidents for novel fields of offshore engineering research which do not have as much data as the oil and gas sector, namely, in terms of wave energy, offshore wind foundations etc... Please highlight this at L105 or in the Conclusions section.
This is another good suggestion. We opted to reflect on this point in the conclusion and have added additional text at line 635.
11. S1.1.1. Is this section is too small can this be joint to the next version?
We understand where the reviewer is coming from but are opting to leave this section as is. It serves as a way to organization the literature review around common themes.
12. L124 - who found that? is there a reference?
Good catch. A reference has been added.
13. L154 - a comment should be given to the uncertainty caused by Climate change as well. Most structures have been designed without any consideration on potential uncertainty and increased variability of extreme phenomena caused by climate change.
The reviewer makes a good point, and we agree. Extreme weather is indeed one of the biggest contributors to structural fatigue and that will likely become an even bigger factor with climate change. We have added additional at line 161.
14. Comment - not mandatory - in section 1.1.1.2 or 1.1.1.3 some references could be given on oil spills caused by such events and conditions as the ones you are describing, as this as a huge impact on local habitats, fauna and flora. An example here: DOI 10.5894/rgci-n65
Thank you for the suggestion. We added the additional reference.
15. Comment - Sincere congratulations to the authors for the large and interesting data base analysed and described in section 2. It can be of great importance to further studies.
Thank you, we appreciate it! We look forward to how further studies apply these data.
16. L348 - environmental data?
Not sure what the reviewer is referencing with this comment.
17. Question - interesting SVD and PCA analysis were applied to reduce the set of variables to the most relevant ones. However, a note should be included for the benefit of the reader that this does not ensure that other important values might be left aside since there is a reduction to a smaller set given by this analysis.
This is a good point. We have added additional text at line 341 with a note to readers.
18. Fig 3 - what does the colour scale stands for?
Good question. Rather than plot several thousand points in a scatterplot, we use the color to represent the number of points within a given area (with associated values). Thus, red colors indicate that there are higher numbers of points in the scatterplot at a given location while blue colors indicate fewer scatterplot points. The fit-line is based on the underlying scatterplot of data, but the color is visual generalization. We added text clarifying this at lines 423.
19. Comment - sometimes in these type of analysis if the order of magnitude of different values is different, say for example MRWG in comparison to C5, may have an influence on the % information explained by different vectors. Thus often a standardirization of all variables is applied. Have you considered this?
We have. Indeed, prior to running the statistical and SVD analysis we z-score standardized all variables of interest to make them more comparable. We have emphasized this in lines 345.
20. L505 - 509 - This surely has something to do with design situations. Larger water depths can be related to larger wave heights and thus further loading and fatigue problems. On the other side small water depths may correlate for example with breaking waves at the platforms which may decrease the lifetime of the platform...This should be clarified a bit better, by looking to at least some examples in the data base that lead to this intriguing relationship behaviour.
That is an excellent point. Water depth is indeed related to wave height. Through the SVD procedure we found depth and wave height be correlated, so opted to use wave height instead. We have added additional text at line 520 to explain the relationship between wave height and depth and offer an additional explanation for the pattern we see in the data which is displayed in Figure 4.
21. Fig. 5 caption seems to be away from the page...please place it in the proper place.
We think this might be due to formatting issues during the conversion from word to pdf. We will be sure to keep an eye out for it following conversion of the revised manuscript.
22. L610 - or benefit from the similar analysis applied to smaller sets of variables related to specific design aspects and components of lifetime integrity reduction?
Good point. We have added text noting this additional possibility.
23. L612-614 - ok that is fine, but at least partially your analysis has numerous applications to marine renewable energy applications including offshore wind and so on. This aspects needs to be highlighted here.
We agree and have added additional text to the conclusion where we reflect on how this work could by applied for renewable energy applications.
Round 2
Reviewer 1 Report
All review comments were addressed in this reviewed version of the manuscript.
