Catalytic Conversion of Oil in Model and Natural Reservoir Rocks

Round 1

Reviewer 1 Report

This work studies the catalytic effect of metal oxides and natural rocks on low-temperature oil cracking as well as the effect of water. The experiments are well designed and the results are useful for unravelling the nature of low-temperature catalytic cracking of oil. My suggestions to improve the manuscript are listed below. 

In Section 3: The properties of the oil, rock and additives as well as the detailed design of experiments should be introduced in Section 2 Materials and Methods. 

It is better to present all the DTA and DTG curves in one Figure. The data in Table 1 only include temperature stages but no mass loss which is important for the estimation of the catalytic effects. 

Line 134, Muscovite in sediments act as detrital clastic rather than cement. 

The following publication (Qi et al., 2023) reviewed the controlling factors (e.g., temperature, pressure, catalysis, water, oil compositions) of the thermal degradation of oil in detail. Please refer to the papers published:

Qi, Y., Cai, C., Sun, P., Wang, D., Zhu, H., 2023. Crude oil cracking in deep reservoirs: A review of the controlling factors and estimation methods. Petroleum Science. https://doi.org/10.1016/j.petsci.2023.03.006 

Some minor suggestions:

Line 85: what is the meaning of “fraction ≤ 0.4”?

Line 87: the unit of density?

Line 89 used “% by weight” but other places % wt. Please unify them.

Line 120: The format of Tmax1 should be modified.

Author Response

Dear Editor.

The authors thank you and the reviewers for their careful consideration of the manuscript and their comments.

We agree with all comments and have tried to correct them.

1. Description of oil properties and the method of obtaining oil-saturated rocks, we added to part 2 Materials and methods and removed from part 3.

2."Muscovite often acts as a cementing material" we removed from the text.

3. We have read the review and referred to it in the introduction.

4."fraction ≤ 0.4" means that it is a rock with a particle size of less than 0.4mm.

5. Density units g/cm3.

All corrections have been made to the article.

Unfortunately, we cannot provide the original TA curves, since the degivatograph has recently broken down and all the information on it has been lost. But since only one oil was used to prepare oil-saturated rocks, the shape of the curves is the same, only the temperatures of the various stages differ, which is reflected in Table 1.

Corrected article in the attached file.

Kind regards,

Ekaterina Okhotnikova

Reviewer 2 Report

In this paper, the authors mainly studies the distribution characteristics of oil products after oil saturation in carbonate rock for one week at normal temperature (25 ℃), and analyzes the degradation mechanism. However, the catalytic effect of several metal oxides analyzed in 3.1 is not well connected with the subsequent use of carbonate rock as catalyst. The content logic needs to be strengthened.

1.       Line 37. The sentence “the duration of conversion processes in natural conditions give the same result as high temperature.” should be rewritten.

2.       The introduction section is too simple, and the research status in the field needs to be more comprehensive.

3.       The Materials and Methods section lacks a proper description of the oil sample.

4.       Line 108, Fig 1 shows the DTA and TG curves, not DTA and DTG curves as descripted in Line 97. Furthermore, some references are required in this paragraph to support the analysis of the thermal oxidative degradation of oil.

5.       The mass losses and the enthalpy of three stages the authors said Line 104 to 107 can’t be seen in Table 1.

6.       Line 166. The distribution of normal alkanes in initial oil as shown in fig 2a was very strange, and I hope the authors could verify it through a repeated test.

7.       The carbonate rock used in section 3.2 has complex composition that contained many other types of minerals. Therefore, the experimental results obtained above cannot directly provide accurate guidance for this part of the experiment.

8.       Line 184. The O contents of oil samples are very important for analyzing their oxidative degradation mechanism. It is recommended to add them to Table 3.

There is no problem with the language, but some of the discussed sentences are not expressed very clearly.

Author Response

Dear Editor.

The authors thank you and the reviewers for their careful consideration of the manuscript and their comments.

1-3. The introduction and experimental part have been corrected.

4. DTG curve has been added.

5. Mass losses have been added to Table 1.

6. Ashalchinskaya oil is heavy and biodegraded. It practically does not contain n-alkanes. This is also noted in the work [Study of the composition of crude oil in the process of biodegradation. Petrov S.M., Ibragimova D.A., Ivanova I.A., Ruleva A.F. 17th International Multidisciplinary Scientific Geoconference SGEM 2017. Conference proceedings. 2017. С. 493-500.]. Initial chromatograms have been added in supplementary materials.

7. The natural carbonate rock contains Al₂O₃, Cr₂O₃, MgO, so these oxides were used as additives.

8. The oxygen content has been added to the article.

Corrected article in the attached file.

Kind regards,

Ekaterina Okhotnikova

Reviewer 3 Report

 

After reading the article “Catalytic Conversion of Oil in Model and Natural Reservoir 2 Rocks", my recommendation is major revision since there are too many issues in this manuscript which need more explanation, re-interpretation of experimental data and additional experimental data (see general comments and detailed list of comments and questions).  

Additionally experimental data (TGA/DTA, GC-FID chromatograms, FTIR spectra) are missing and should be explicitly included in the manuscript or in Supplementary Material.

General comments

1. Experimental section is incomplete. More experimental details should be given (see detailed list of comments and questions).

2. TGA/DTA curves, FTIR spectra and GC-FID chromatograms should be included (see detailed list of comments and questions).

3. No statistics or error bars are reported and should be included (see detailed list of comments and questions).

4. No enthalpies are reported in this manuscript. Therefore there is no experimental evidence for statements or data on this parameter (see detailed list of comments and questions).

5. No information is found on the procedure for the quantification of GC-FID data.  

6. Oxygen content should be reported since it is an important and essential parameter considering the topic of catalytic conversion and oxidation.

7. Calculation of FTIR spectra coefficients cannot be used to obtain reliable quantitative data since selected wavenumbers are not selective towards functional groups  for the intended purpose. Additionally FTIR spectra used for such calculations should be included (see detailed list of comments and questions) to judge such approach.

If authors are willing to consider these comments and questions, and perform an in-depth revision, the revised paper can be reconsidered for publication.I do not recommend the publication of this manuscript in its present form. 

A detailed list of comments and questions is addressed to the authors.  

Detailed list of questions and comments:

1. Introduction

p.1 Lines 26-27: “the development of new technologies for complex thermal impact on oil reservoirs including with catalysts”: not a clear formulated statement which needs rephrasing. Please comment.

p.1 Lines 37-38: “natural conditions” and “high temperatures” should be better described. Please comment.

2. Materials and Methods

p.2 Lines 51-58: Abbreviation “SARA” should be explained when first introduced in the paper. LC adsorption chromatography conditions should be given in detail (type of LC apparatus, injection volume, characteristics of adsorption columns. It is not clear how purity of the four fractions can be controlled by their refractive index. Please comment.

p.2 Lines 59-63: Which compounds is used for calibration? Please comment.

p.2 Lines 64-67: resolution? Detector? Injection volume? Carrier gas? Please comment.

p.2 Lines 76-81: More details on GC-FID conditions are required: temperature program? GC column characteristics? Please comment.

3. Results  

p.3 Line 95: What is the size fraction of the rock material? Please comment.

p.3 Line 97: TG and DTA curves are shown, DTG curve should also be included. In Fig.1 no scale is found for the DTA curve. Please comment. 

p.3 Lines 97-98: DTA and TG curves of oil-saturated quartz sand with additives of metal oxides should be included in the paper (or in the Supplementary material) for a better comparison and interpretation of results presented in Table 1. Please comment.

p.3 Lines 102 and 104: “polycyclic aromatic structures” instead of “polyaromatic structures”

p.3 Line 103: “These processes are accompanied endo thermic effect”: This statement requires rephrasing. Please comment.

p.3 Line 106:  No enthalpies (in kJ/mol) are found in Table 1, only temperatures are presented. Please comment.

p.3 Line 110: What is the experimental error on the temperature ranges and the maximum temperature? These data should be included in Table 1 for a better statistical evaluation of obtained data Please comment..

p.3 Line 111-120 and p.4 Lines 121-124: It is impossible for the reader to judge these data as TG/DTA curves of samples 2-5 are not shown. Therefore the curves should be explicitly included in the same way as in Figure 1 in this paper or in the Supplementary Material. Please comment.

p.4 Lines 125-136: No enthalpies are reported in this manuscript. Therefore there is no experimental evidence for statements formulated in Lines 121-136. Please comment.

p.4 Lines 34-40: No experimental evidence is given to support such statement. Please comment.  

p.4 Lines 138-145: What is the particle size of natural rock material and model-oil saturated material? Please comment.

p.4 Line 150: Standard deviations should be included in Table 2.  Please comment.  

p.4 Line 160: GC-FID chromatograms should be included in the Supplementary Material. How quantification was performed to obtain the data presented in Figure 2? No experimental details are found in section 2, Materials and Methods. Please comment.

p.4 Line 160: How can GC-FID differentiate between n. alkanes and isoprenoid alkanes? Are these acyclic isoprenoid alkanes? Please comment.

p.5 Line 160: Experimental error bars should be included in Figure 2. Figure 2 should be magnified. Please comment.

p.5 Line 176: Experimental error should be included in Table 3 when comparing data. Please comment.

p.5 Line 177: “than in initial oil” instead of “than in ones in initial oil”

p.5 Lines 180-181: “stabilizing the active particles formed at destruction of alkyl-substituted naphthenoaromatic molecules”: This statement is not clear to me. Please comment.

p.5 Lines 182-184: Why sulfur content decreases in polar and nonpolar resins in sample Oil ex wet? Please comment.

P.5 Mine 185: Why O content is not determined? Please comment.

p.5 Lines 185-189: FTIR spectra should be included in this paper or in the Supplementary Material as a support for data reported in Table 4. Please comment.

p.6 Line 190: “pendular vibrations of the methylene group”: Not clear to me. Rocking vibration of methylene group at 720 cm-1 in long chain alkanes. Please comment.

p.6 Lines 188-194: Selected wavenumbers are not specific enough for calculating spectral coefficients to quantify methyl, carboxyl and sulfoxide functionalities, except for 720 cm-1 (long chain aliphatic hydrocarbons) as presented in Table 4:

Spectral coefficient R: the band at wavenumber at 1380 cm-1 can be assigned to a C-H vibration present as well in methyl as in methylene is in overlap with different C=O containing groups (such as aldehydes and ketones) and not only to carboxylic acids (as mentioned on p.5 line 187.

Spectral coefficient O2: the band 1030cm-1 can also be assigned to C-O-C vibration.

Please comment.

Additionally resolution of the FTIR spectra (which should be explicitly included). Please comment.

p.6 Lines 195-211: Therefore discussion of results reported in Table 4 are not reliable and such conclusions can be formulated. Please comment.

p.6 Line the increase of the spectral coefficient O2 can also be the result of an increase of C-O-C by oxidation. Therefore it is necessary to include oxygen content in Table 3. Please comment.

p.6 Line 202: Which type of polycyclic compounds?” Please comment.

p.6 Line 203: Presence of sulfonic groups should be confirmed FTIR (IR absorption around 1345 cm-1). Please comment.

p.6 Line 207: “(Table 3)” instead of “(how elemental analysis (Table 3) shows)”

p.7 Line 222: Experimental errors should be induced in Table 5. Please comment.

p.7 Line 225: “polycyclic aromatic molecules” instead of “aromatic hydrocarbon molecules”.

4. Conclusions

Conclusions should be completely revised taken into account all previous comments. Please comment.

 

 

 

 

 

See my comments in the detailed list of comments and questions to the authors.

Author Response

Dear Editor.

The authors thank you and the reviewers for their careful consideration of the manuscript and their comments.

1. Part 2 Materials and Methods has been corrected. More experimental details have been added.
2. Typical IR spectrum high molecular weight components and chromatograms were added to supplementary materials. Unfortunately, we cannot provide the original TA curves, since the degivatograph has recently broken down and all the information on it has been lost. But since only one oil was used to prepare oil-saturated rocks, the shape of the curves is the same, only the temperatures of the various stages differ, which is reflected in Table 1.
3. Experimental errors have been added for all methods in part 2 Materials and methods.
4. The TA method, in contrast to the calorimetry method and TG-DSC, does not allow to determine the enthalpy in kJ/mol. It can only estimate the magnitude of the effect in conventional units. Therefore, we removed the discussion of enthalpy from the article, and discuss only the temperatures of various stages of thermal-oxidative degradation. We used the thermal analysis method on a derivatograph because it uses large weights of the sample, in contrast to the TG-DSC, which allows us to obtain reproducible results for rather heterogeneous samples, such as oil-saturated rocks.
5. SARA analysis was carried out by the preparative method in glass chromatographic columns. A detailed description of the method has been added to Part 2, Materials and Methods.
6. Data on oxygen content was added to the article. The CHNS method does not allow the direct determination of the oxygen content, unlike the method CHNSO. By subtracting the content of C, H, N, S from 100%, the total content of oxygen and metals can be estimated.
7. Deciphering the IR spectrum of high-molecular oil components is an extremely difficult task, since these are not individual compounds, but a mixture of polycyclic naphthenoaromatic molecules. The exact structure of resins and asphaltenes is not fully known and may vary depending on the oil in which they are contained. Therefore, to characterize the structural group composition resins and asphaltenes, a set of main absorption bands is widely used. This approach is widely described in the literature, for example [Shabalin, K. V.; Foss, L. E.; Borisova, Y. Y.; Borisov, D. N.;Yakubova, S. G.; Yakubov, M. R. Study of the heavy oil asphaltenes oxidation products composition using EPR and IR spectroscopy. Pet Sci Technol 2020, 38(22), 992–997. https://doi.org/10.1080/10916466.2020.1802484, Petrova L.M., Abbakumova N.A., Foss T.R., Romanov G.V. Structural features of asphaltene and petroleum resin fractions. Petroleum Chemistry. 2011. Т. 51. № 4. С. 252-256.]. To characterize sulfide groups in resins and asphaltenes, band 1030 is used, not 1345, since band 1345 is overlapped by band 1380.

p.4 Line 160: How can GC-FID differentiate between n. alkanes and isoprenoid alkanes? Are these acyclic isoprenoid alkanes? Please comment.

Isoprenoid alkanes are acyclic branched alkanes with a regular structure. These compounds are a biomarker of oil and are found in almost all oils (except for highly biodegraded ones).

Why sulfur content decreases in polar and nonpolar resins in sample Oil ex wet? Please comment.

The sulfur content is reduced due to cracking reactions that remove heteroatoms, as in hydrotreating.

The experimental data have been revised taking into account the comments received. The article has been corrected. We tried to take into account all comments and answer all questions.

Corrected article in the attached file.

Kind regards,

Ekaterina Okhotnikova

Round 2

Reviewer 2 Report

The authors have made substantial revisions to the manuscript in accordance with the suggestions provided by the reviewers. The changes made have significantly strengthened the overall quality and coherence of the manuscript.

Author Response

Dear Editor.

The authors thank you and the reviewers.

Thank you ever so much for taking the time to help us!

Kind regards,

Ekaterina Okhotnikova

Reviewer 3 Report

I have read the revised article “Catalytic Conversion of Oil in Model and Natural Reservoir Rocks", including the answers to the comments and questions of the reviewers.

Authors have addressed the comments and questions of the reviewer and have implemented changes and additional data and information. I am convinced that the overall quality of the article has improved considerably and I support the publication of the revised version of the paper.

Minor comments:

Line 69: “additive.” instead of “addictive.”

Line 71: “were used for the preparation of model oil-saturated rocks” instead of “were used for the preparation model oil-saturated rocks”.

Line 73: “for the preparation of natural oil-saturated rocks “ instead of “for the preparation natural oil-saturated rocks”

Line 156: “The TG, DTG and DTA curves” instead of “The TG and DTA curves”

Line 169: “DTA, TG, and DTG curves of oil-saturated quartz sand without additives” instead of “DTA and DTG curves of oil-saturated quartz sand without additives”

p.4 Fig.1: No scale is found for the DTA curve.

 

 

See minor comments.

Author Response

Dear Editor.

The authors thank you and the reviewers for their careful consideration of the manuscript and their comments.

The article has been corrected. All comments have been taken into account.

Derivatograph Q - 1500D does not determine the magnitude of thermal effects. The data processing program of the derivatograph builds a DTA curve from a comparison of the temperatures of the standard and the sample. However, the processing program does not give a scale for it. Therefore, in Fig. 1 there is no scale for DTA curve. I’m sorry, there’s nothing we can do about it.

Corrected article in the attached file.

Thank you ever so much for taking the time to help us!

Kind regards,

Ekaterina Okhotnikova