Technical and Environmental Feasibility Study of the Co-Production of Crude Oil and Electrical Energy from Geothermal Resources: First Field Trial in Colombia
, Natalia A. Cano 1, Gordon Foo 2, David Jaramillo 2, Daniel Martinez 2, Manuel Gutiérrez 2, Javier Pataquiba 2, Juan Rojas 2, Farid B. Cortés 1,* and Camilo A. Franco 1,*Round 1
Reviewer 1 Report
This article presents a study of crude Oil and electrical energy co-production using ORC. The text is not clear. The reader does not know if it is a theoretical study or the authors analyse the existing power. Also, the introduction and abstract are too long. The authors include unnecessary information. For example, the comparison with the Carnot efficiency not is essential. Also, the exergy concept is not used in the analysis. I recommend rejecting this paper.
Author Response
Medellín, February 25, 2022
Ms. Freya Feng
Assistant Editor
Processes
RE: Response to reviewer’s comments regarding manuscript ID: processes-1609011
Dear Ms. Freya Feng,
We would like to thank you for securing a prompt review of our manuscript titled; “Technical and Environmental Feasibility Study of the Co-Production of Crude Oil and Electrical Energy from Geothermal Resources: First Field Trial in Colombia.” We have answered all the comments raised by the reviewer 1 and have thoroughly revised the manuscript accordingly. We found the comments helpful and believe that our revised manuscript represents a significant improvement over our initial submission.
The detailed response (in blue) to the reviewer’s comments, suggestions, and questions (in black), and the revised manuscript are attached. As suggested, any track changes, highlights, or font colors in our revised manuscript have been removed and we believe now that our manuscript is publishable in Processes.
Please do not hesitate to contact us if you have any further questions.
Sincerely yours,
The authors
Responses to the reviewer´s suggestions for the manuscript: Technical and Environmental Feasibility Study of the Co-Production of Crude Oil and Electrical Energy from Geothermal Resources: First Field Trial in Colombia
Reviewer 1.
Comment: This article presents a study of crude Oil and electrical energy co-production using ORC. The text is not clear. The reader does not know if it is a theoretical study or the authors analyse the existing power. Also, the introduction and abstract are too long. The authors include unnecessary information. For example, the comparison with the Carnot efficiency not is essential. Also, the exergy concept is not used in the analysis. I recommend rejecting this paper.
Response: We thank the reviewer for her/his effort to review our work. We believe it has been greatly improved during this revision regarding organization and content. It is worth mentioning that this study includes the first field trial of co-production of crude oil and electrical energy from geothermal resources. This field trial was performed in the Casanare department in two different oilfields, as shown in Figure 2 of the manuscript. The field trial started in early 2021. Figure 5 of the article shows the ORC system located in the field, and Figure R1 shows a picture of the Colombian Minister of Energy in an oilfield with the ORC system. Also, Table 3 and Figure 6 show the measured (not theoretical calculation) power generation during a certain time frame. In addition, theoretical calculations to compare reductions in CO2 emissions from conventional oil production regarding different scenarios for power co-generation using geothermal resources, as shown in Section 3.3.
Figure R1. Picture of Colombian Minister of Energy and an oilfield worker nexto to the ORC equipment in field. Source: https://www.larepublica.co/economia/empieza-el-primer-piloto-para-la-generacion-de-energia-electrica-con-geotermia-3143828
Also, we agree with the reviewer’s comment regarding the length of the abstract and introduction, which were shortened from Lines 15-19 and Lines 71-85, 92-94, respectively.
For the analysis carried out, the Carnot efficiency gives an idea about the operation of the technology in ideal conditions of non-irreversibility. In this way, this value indicates how far the operation of the real heat engine is from a theoretical ideal, allowing the Carnot efficiency to be used as a comparison value. For the analysis of the performance of thermal machines such as organic Rankine cycles, the Carnot efficiency allows a more detailed analysis. However, we agree with the reviewer’s in her/his opinion regarding the importance of this parameter for the article. Hence, text in Lines 481-488 was deleted and column five of Table 3 was removed. Also, Lines 508-510 were modified in Section 3.2., as follows:
“The real efficiency of the ORC unit depends on process experiences irreversibilities, such as heat transfer due to finite temperature difference, and fluid expansion, among others.”
In addition, it is important to mention that the concept of Exergy is defined in the article as follows:
For the characterization of each field, the energy production potential is calculated through the exergy concept, a thermodynamic property that indicates the maximum amount of work that can be extracted from a particular energy source. The exergy (available energy) in the subject fields is calculated as shown in Equation 1.
|
|
(1) |
where B is the exergy flow of a current (kW); m is the mass flow (kg s-1); h and h0 are the enthalpies at the system temperature and pressure, and ambient conditions, respectively (kJ kg-1); and s and s0 are the entropy at the system temperature and pressure, and ambient conditions, respectively (kJ kg-1 K-1). Finally, T0 is the ambient temperature (K).
However, in order to avoid misinterpretations and provide a more profound discussion regarding exergy, the following was included:
Section 3.1:
“It should be clarified that energy and exergy flows are shown for comparative purposes. Energy is a global measure of the capacity to produce work in the analyzed energy source, but it does not consider the thermodynamic irreversibilities inherent to all real processes. On the other hand, the exergy considers all the irreversibilities through the generated entropy, although it does not consider the levels of applied technologies (technological conversion efficiency). In addition, these two measurements are presented as evaluation parameters of the geothermal resource, although it is clarified that the exergy is a more realistic value.”
Section 3.3.1.
“When analyzing the information shown in Table 4 and Table 5, it can be identified that the OFA field has a greater energy need. This can be explained by the dynamics of OFA, where there is a greater production of fluids (see Figure 3 and Figure 4). In addition, when part of the input to the system comes from the geothermal co-production, a decrease of 28% and 59% in field gas can be identified for OFA and OFB, respectively. The decrease in OFB can be explained due to the lower consumption of field gas where the co-production of geothermal energy has a greater impact in terms of energy consumption.”
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The article: "The Role of Conventional and Unconventional Resources in Energy Transition" carries out a complete analysis of the energy potential of energy usage in a platform. Therefore, I think the article is suitable for publication. Nevertheless, I believe it is necessary to clarify some of this reviewer's doubts on a round of revision.
First of all, this comment was a litle strange for me:
"The production of geothermal power from oil fields has already been piloted success fully in the USA and China [54,64,67]. Work by Augustine et al. [61] estimated the potential for this co-produced fluid geothermal power generation in the United States using 143 three models for electrical generation potential: exergy, the Massachusetts Institute of Technology (MIT) model, and a commercially available “off-the-shelf” (COTS) model"
The idea is to find electrical generation potential, being the exergy analysis the thermodynamic property that gives a clue of this capability. I was a litle lost with the significance and meaning of the MIT model. A little explanation would help the reader not to stop at this point.
In figure 4 I was a litle concerned regarding the energy flow. Since the enthalpy, for instance, is only related to temperature and pressure in relation to one reference, it can not describe an input such as exergy. Since the enthalpy entering the system is the enthalpy of formation summed with the enthalpy variation due to pressure and temperature changes. With exergy, this is not an issue because there is a variation regarding reference.
Another issue: "The highest carbon 34 footprint reduction is found in Scenario 1, which replaces 100% of the liquid fuel consumption with 35 purchased gas (gas provided by a third and treated outside the system’s limits),..." Did authors considered the footprint to produce this gas?
The remainder of the article is quite good, with several discussions that are particular to the energy planning scenario of Colombia, nevertheless, new in literature. For example, it is interesting to see in literature several articles looking for "medium enthalpy" or "mediun heat" coming for temperature over 90 oC. Still, few uses the idea of this article.
Author Response
Medellín, February 25, 2022
Ms. Freya Feng
Assistant Editor
Processes
RE: Response to reviewer’s comments regarding manuscript ID: processes-1609011
Dear Ms. Freya Feng,
We would like to thank you for securing a prompt review of our manuscript titled; “Technical and Environmental Feasibility Study of the Co-Production of Crude Oil and Electrical Energy from Geothermal Resources: First Field Trial in Colombia.” We have answered all the comments raised by the reviewer 2 and have thoroughly revised the manuscript accordingly. We found the comments helpful and believe that our revised manuscript represents a significant improvement over our initial submission.
The detailed response (in blue) to the reviewer’s comments, suggestions, and questions (in black), and the revised manuscript are attached. As suggested, any track changes, highlights, or font colors in our revised manuscript have been removed and we believe now that our manuscript is publishable in Processes.
Please do not hesitate to contact us if you have any further questions.
Sincerely yours,
The authors
Responses to the reviewer´s suggestions for the manuscript: Technical and Environmental Feasibility Study of the Co-Production of Crude Oil and Electrical Energy from Geothermal Resources: First Field Trial in Colombia
Reviewer 2.
Comment: The article: "The Role of Conventional and Unconventional Resources in Energy Transition" carries out a complete analysis of the energy potential of energy usage in a platform. Therefore, I think the article is suitable for publication. Nevertheless, I believe it is necessary to clarify some of this reviewer's doubts on a round of revision.
Response: We thank the reviewer for her/his opinion regarding the article’s quality. The suggestions were considered and we believe that the manuscript is greatly improved for publication.
- First of all, this comment was a litle strange for me:
"The production of geothermal power from oil fields has already been piloted success fully in the USA and China [54,64,67]. Work by Augustine et al. [61] estimated the potential for this co-produced fluid geothermal power generation in the United States using 143 three models for electrical generation potential: exergy, the Massachusetts Institute of Technology (MIT) model, and a commercially available “off-the-shelf” (COTS) model"
The idea is to find electrical generation potential, being the exergy analysis the thermodynamic property that gives a clue of this capability. I was a little lost with the significance and meaning of the MIT model. A little explanation would help the reader not to stop at this point.
Response: We thank the reviewer for his/her comment. It is important to mention that the exergy model is based on the theoretical limit of the maximum amount of work that can be obtained by bringing the resource to ambient or dead conditions. Meanwhile, MIT model works with the theoretical efficiency for ORC , as follows:
|
|
(R1) |
where T is the temperature of coproduced fluid (°C) and is the thermal efficiency of the ORC (%).
Also, the Commercially Available "off-the-shelf" (COST) model is derived from performance curves of ORC system published by Pratt & Whitney [69].
In this sense, the following was included in the Introduction to clarify the idea:
“The exergy model is based on the theoretical limit of the maximum amount of work that can be obtained by bringing the resource to ambient or dead conditions. Meanwhile, the Massachusetts Institute of Technology (MIT) model works with the theoretical efficiency for ORC [58] and the Commercially Available "off-the-shelf" (COST) model is derived from performance curves of ORC system [59].”
- In figure 4 I was a little concerned regarding the energy flow. Since the enthalpy, for instance, is only related to temperature and pressure in relation to one reference, it can not describe an input such as exergy. Since the enthalpy entering the system is the enthalpy of formation summed with the enthalpy variation due to pressure and temperature changes. With exergy, this is not an issue because there is a variation regarding reference.
.
Response: We thank the reviewer for his/her observation. Precisely, Figure 4 was proposed to show the differences between the concept of energy and exergy. The calculations shown in Figure 4 are performed for two flow cases. In addition, the document emphasizes the difference in concepts and the importance of exergy when considering a reference state for thermal, mechanical and chemical potentials (dead state) between lines 420 and 428. To give specificity about the Figure and its interpretation when comparing energy and exergy, the following was added in Section 3.1:
“It should be clarified that energy and exergy flows are shown for comparative purposes. Energy is a global measure of the capacity to produce work in the analyzed energy source, but it does not consider the thermodynamic irreversibilities inherent to all real processes. On the other hand, the exergy considers all the irreversibilities through the generated entropy, although it does not consider the levels of applied technologies (technological conversion efficiency). In addition, these two measurements are presented as evaluation parameters of the geothermal resource, although it is clarified that the exergy is a more realistic value.”
- Another issue: "The highest carbon 34 footprint reduction is found in Scenario 1, which replaces 100% of the liquid fuel consumption with 35 purchased gas (gas provided by a third and treated outside the system’s limits),..." Did authors considered the footprint to produce this gas?
Response: We thank the reviewer for his/her question. The carbon footprint for the purchased gas was not assumed within the analysis performed in this manuscript. To justify this decision, the boundaries system and the activity to which the analysis is carried out are taken into account, that is the energy production in an oil field. For purchased gas, the carbon footprint is assumed by the supplier, for whom a payment is made for the activity. On the other hand, for the gas produced in the field (field gas) the carbon footprint was considered because the treatment is included within the activities of the field. This is detailed in Section 3.3.1, as follows:
“It is assumed that the gas supplier is responsible for the environmental impacts related to the production of the sold gas. Diesel consumption occurs when there is a shortage of gas, or when it is necessary to reinforce the energy generation system.”
Author Response File: Author Response.pdf
Reviewer 3 Report
This paper represents a great contribution to the energy sector with an emphasis on reducing global greenhouse gas. The novelty approach of co-production of crude oil and electrical energy from geothermal resources in Columbia was conducted and studied. The manuscript has been prepared carefully and it seems that a lot of effort has been invested in this research, but a couple of objections are listed below:
In the introduction, a good background of this research problem is given and an adequate context is set, as well as an overview of solutions or approaches that have been tried by other authors. However, this section is too long, there is too much information that is not closely related to the topic and goal of the paper.
For example, data on the use of solar and wind energy in Colombia are not significant data for this research Line 71-85, Page 2.
Please shorten the introduction by removing unnecessary information.
Line 237, Page 5 Provide information about purchased gas.
Line 329-331, Page 8 The methodology and equipment of analysis carried for the characterization of the psychochemical properties of the produced water is not described.
Line 334, Page 8 Table 1, no statistical significance, no information on the number of repetitions.
The general objection is that the results were not subjected to statistical analysis. More detailed mathematical processing of all obtained data is needed, which would show significant differences between the samples.
Mark in the table or below the Table 4, volumetric flows and energy flows. Comment on the results in the Table 4, Page16
Compare the results from the Table 4, with the results from the Table 5
Include more discussions for Figure 6, Page 14
Line 507-509, “The benefits realized through the implementation of these systems are both environmental, as a reduction in carbon footprint, and financial, through lowering of fuel costs.” Since no economic and environmental calculations have been made, this cannot be stated as a claim. Prove or cite this as a presumption.
Line 619-631, Page 18 These sentences are somehow more the opinion and assumptions of the author. Since the paragraph is in the results section, it may be better to shorten this paragraph and put it in conclusion.
Line 653-658, Page 19, This is repeated several times in the text, remove.
Line 674, Table 8 correct as Table 9
Author Response
Medellín, February 25, 2022
Ms. Freya Feng
Assistant Editor
Processes
RE: Response to reviewer’s comments regarding manuscript ID: processes-1609011
Dear Ms. Freya Feng,
We would like to thank you for securing a prompt review of our manuscript titled; “Technical and Environmental Feasibility Study of the Co-Production of Crude Oil and Electrical Energy from Geothermal Resources: First Field Trial in Colombia.” We have answered all the comments raised by the reviewer 3 and have thoroughly revised the manuscript accordingly. We found the comments helpful and believe that our revised manuscript represents a significant improvement over our initial submission.
The detailed response (in blue) to the reviewer’s comments, suggestions, and questions (in black), and the revised manuscript are attached. As suggested, any track changes, highlights, or font colors in our revised manuscript have been removed and we believe now that our manuscript is publishable in Processes.
Please do not hesitate to contact us if you have any further questions.
Sincerely yours,
The authors
Responses to the reviewer´s suggestions for the manuscript: Technical and Environmental Feasibility Study of the Co-Production of Crude Oil and Electrical Energy from Geothermal Resources: First Field Trial in Colombia
Reviewer 3.
Comment: This paper represents a great contribution to the energy sector with an emphasis on reducing global greenhouse gas. The novelty approach of co-production of crude oil and electrical energy from geothermal resources in Columbia was conducted and studied. The manuscript has been prepared carefully and it seems that a lot of effort has been invested in this research, but a couple of objections are listed below.
Response: We sincerely thank the reviewer for her/his opinion on the novelty and quality of our work. This certainly encourages us to keep the good work.
- In the introduction, a good background of this research problem is given and an adequate context is set, as well as an overview of solutions or approaches that have been tried by other authors. However, this section is too long, there is too much information that is not closely related to the topic and goal of the paper.
For example, data on the use of solar and wind energy in Colombia are not significant data for this research Line 71-85, Page 2.
Please shorten the introduction by removing unnecessary information.
Response: We thank the reviewer for his/her observation. The suggestions made by the reviewer are considered and the sections were deleted in order to make the introduction shorter and more concise.
- Line 237, Page 5 Provide information about purchased gas.
Response: We thank the reviewer for his/her observation. However, the specific gas composition is required to be private due to confidentiality issues. Nevertheless, for the purpose of this paper, the heat value employed was 40.44 MJ m-3 as reported in Table 4 and Table 5.
- Line 329-331, Page 8 The methodology and equipment of analysis carried for the characterization of the psychochemical properties of the produced water is not described.
Response: We thank the reviewer for his/her observation. The methodology along with the standards applied for each water characterization was described in section 2.1 as shown below:
“The alkalinity of the samples was measured using a titrimetric method considering the SM2320 B method [68]. On the other hand, for the measurement of chlorides, the stand-ardized argentometric method was used based on the S.M. (4500 - Cl-B) [68]. In the case of water conductivity, the electrometric method was used according to the S.M. (2510B) standard [68]. For the pH, a potentiometric method based on the S.M. (4500-H + B) standar was employed [68]. Finally, the total dissolved solids were obtained from a gravimetric process based on the S.M. (2540 C) standard [68]. It should be mentioned that all measurements were made by triplicate.”
- Line 334, Page 8 Table 1, no statistical significance, no information on the number of repetitions.
Response: We thank the reviewer for his/her observation. The standard deviation of each measure was added to the information shown in Table 1 in order to demonstrate the statistical treatment of the deviation in each measure, and Section 2.1., as follows:
“The alkalinity of the samples was measured using a titrimetric method considering the SM2320 B method [68]. On the other hand, for the measurement of chlorides, the stand-ardized argentometric method was used based on the S.M. (4500 - Cl-B) [68]. In the case of water conductivity, the electrometric method was used according to the S.M. (2510B) standard [68]. For the pH, a potentiometric method based on the S.M. (4500-H + B) standar was employed [68]. Finally, the total dissolved solids were obtained from a gravimetric process based on the S.M. (2540 C) standard [68]. It should be mentioned that all measurements were made by triplicate.”
Table 1. Physicochemical properties of the produced waters of OFA and OFB.
|
Parameter |
OFA |
OFB |
|
Total alkalinity (mg CaCO3 L-1) |
335.0 ± 3.8 |
271.5 ± 3.1 |
|
Chlorides (mg Cl L-1) |
7624.8 ± 38.1 |
3941.9 ± 19.7 |
|
Conductivity (uS cm-1) |
21600.0 ± 130.0 |
10760.0 ± 65.0 |
|
pH |
7.2 ± 0.2 |
7.6 ± 0.2 |
|
Total disolved solids (mg TDS L-1) |
16686.7 ± 83.4 |
7710.7 ± 46.3 |
- The general objection is that the results were not subjected to statistical analysis. More detailed mathematical processing of all obtained data is needed, which would show significant differences between the samples.
Response: We thank the reviewer for his/her suggestion. It is worth to mention that the mathematical methods here were employed for specific scenarios and time frame (case of interest) of one month, which requires the use of point data obtained directly from the field.
On the other hand, the methods and standards used for the physicochemical characterization of the water samples were specified within the document in section 2.1 as shown below:
“The alkalinity of the samples was measured using a titrimetric method considering the SM2320 B method [68]. On the other hand, for the measurement of chlorides, the stand-ardized argentometric method was used based on the S.M. (4500 - Cl-B) [68]. In the case of water conductivity, the electrometric method was used according to the S.M. (2510B) standard [68]. For the pH, a potentiometric method based on the S.M. (4500-H + B) standar was employed [68]. Finally, the total dissolved solids were obtained from a gravimetric process based on the S.M. (2540 C) standard [68]. It should be mentioned that all measurements were made by triplicate.”
Table 1. Physicochemical properties of the produced waters of OFA and OFB.
|
Parameter |
OFA |
OFB |
|
Total alkalinity (mg CaCO3 L-1) |
335.0 ± 3.8 |
271.5 ± 3.1 |
|
Chlorides (mg Cl L-1) |
7624.8 ± 38.1 |
3941.9 ± 19.7 |
|
Conductivity (uS cm-1) |
21600.0 ± 130.0 |
10760.0 ± 65.0 |
|
pH |
7.2 ± 0.2 |
7.6 ± 0.2 |
|
Total disolved solids (mg TDS L-1) |
16686.7 ± 83.4 |
7710.7 ± 46.3 |
- Mark in the table or below the Table 4, volumetric flows and energy flows. Comment on the results in the Table 4, Page16.
Response: We thank the reviewer for his/her suggestion. It was specified in the table each component with energy and volume. Detailed information on Table 4 and Table 5 was added to Section 3.3.1, as follows:
“When analyzing the information shown in Table 4 and Table 5, it can be identified that the OFA field has a greater energy need. This can be explained by the dynamics of OFA, where there is a greater production of fluids (see Figure 3 and Figure 4). In addition, when part of the input to the system comes from the geothermal co-production, a decrease of 28% and 59% in field gas can be identified for OFA and OFB, respectively. The decrease in OFB can be explained due to the lower consumption of field gas where the co-production of geothermal energy has a greater impact in terms of energy consumption.”
- Compare the results from the Table 4, with the results from the Table 5.
Response: We thank the reviewer for his/her suggestion. Detailed information on Table 4 and Table 5 was added to Section 3.3.1, as follows:
“When analyzing the information shown in Table 4 and Table 5, it can be identified that the OFA field has a greater energy need. This can be explained by the dynamics of OFA, where there is a greater production of fluids (see Figure 3 and Figure 4). In addition, when part of the input to the system comes from the geothermal co-production, a decrease of 28% and 59% in field gas can be identified for OFA and OFB, respectively. The decrease in OFB can be explained due to the lower consumption of field gas where the co-production of geothermal energy has a greater impact in terms of energy consumption.”
- Include more discussions for Figure 6, Page 14
Response: We thank the reviewer for his/her suggestion. An additional paragraph was added to the document with a broader discussion about Figure 6. Additionally, the information shown in Figure 6 was compared with Table 3 in Section 3.2, as follows:
“As shown in Figure 6, there are two zones that describe the energy production. The first zone is characterized by less energy production and high environmental temperatures and is found between 10:00 and 17:00 hours. The second zone, with the highest energy production, is characterized by low environmental temperatures and appears between 10:00 p.m. and 5:00 a.m. As explained above, this behavior is due to the temperature gradient between the energy source (geothermal fluid) and the sink (environment), which is greater in the second zone.”
- Line 507-509, “The benefits realized through the implementation of these systems are both environmental, as a reduction in carbon footprint, and financial, through lowering of fuel costs.” Since no economic and environmental calculations have been made, this cannot be stated as a claim. Prove or cite this as a presumption.
Response: We thank the reviewer for his/her suggestion. To validate the proposed idea, the investigations are cited where environmental and economic analyzes are related in the projects where the use of geothermal resources in oil fields for the production of energy is evaluated. The following research was cited:
- Bennett, K.; Horne, R.N.; Li, K. Power generation potential from coproduced fluids i the Los Angeles basin. Stanford University, 2012.
- Johnson, L.; Simon, D.L. Electrical power from an oil production waste stream. In Proceedings of the PROCEEDINGS of Thirty-Forth Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, 2009.
- Xin, S.; Liang, H.; Hu, B.; Li, K. A 400 kW geothermal power generator using co-produced fluids from Huabei oilfield. Geothermal Resources Council Transactions 2012, 36, 219-223.
- Li, T.; Liu, Q.; Xu, Y.; Dong, Z.; Meng, N.; Jia, Y.; Qin, H. Techno-economic performance of multi-generation energy system driven by associated mixture of oil and geothermal water for oilfield in high water cut. Geothermics 2021, 89, 101991, doi:https://doi.org/10.1016/j.geothermics.2020.101991.
- Akhmadullin, I. Utilization of Co-Produced Water from Oil Production: Energy Generation Case. In Proceedings of the SPE Health, Safety, Security, Environment, & Social Responsibility Conference-North America, 2017.
In addition, a part was added emphasizing the research mentioned in section 3.2:
“The geothermal power production in a oilfield is an example of a transition from non-renewable technologies to renewable energy technologies. The benefits realized through the implementation of these systems are both environmental and financial due to a reduction in carbon footprint, and lowering of fuel costs as reported in previous studies [41,45,48,50,54].”
- Still, Line 619-631, Page 18 These sentences are somehow more the opinion and assumptions of the author. Since the paragraph is in the results section, it may be better to shorten this paragraph and put it in conclusion.
Response: We thank the reviewer for his/her suggestion. The paragraph was summarized and moved to the Conclusion section as shown below:
“Aside from the benefits quantified and confirmed in this investigation, it is clear that more widespread implementation of geothermal energy co-generation systems would be a benefit to the efforts of the oil and gas industry to decarbonize activities. The regulatory precedents may help resolve obstacles that stand in the way of conventional hydrothermal geothermal developments. These regulatory pathways will be key to attracting the interest and investment required to meaningfully develop a geothermal industry in Colombia and further diversifying Colombia’s energy matrix.
This project is an important example of how Colombia can implement innovative strategies to meet increasing energy needs while mitigating the effects of climate change”
- Line 653-658, Page 19, This is repeated several times in the text, remove.
Response: We thank the reviewer for his/her suggestion. The indicated paragraph was removed.
- Line 674, Table 8 correct as Table 9
Response: We thank the reviewer for his/her suggestion. The number of the Table was modified.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
I think that the paper should be improved. The introduction has been reduced, but it is still too long. The exergy analysis is incomplete. You evaluate the exergy resource, but the exergy efficiency of the process is not taken into account. The total exergy could be poor with a resource with high exergy if the process is inefficient from the exergy point of view.
Author Response
Medellín, March 02, 2022
Ms. Freya Feng
Assistant Editor
Processes
RE: Response to reviewer’s comments regarding manuscript ID: processes-1609011
Dear Ms. Freya Feng,
We would like to thank you for securing a prompt review of our manuscript titled; “Technical and Environmental Feasibility Study of the Co-Production of Crude Oil and Electrical Energy from Geothermal Resources: First Field Trial in Colombia.” We have answered all the comments raised by the reviewer and have thoroughly revised the manuscript accordingly. We found the comments helpful and believe that our revised manuscript represents a significant improvement over our initial submission.
The detailed response (in blue) to the reviewer 1 comments, suggestions, and questions (in black), and the revised manuscript are attached. As suggested, any track changes, highlights, or font colors in our revised manuscript have been removed and we believe now that our manuscript is publishable in Processes.
Please do not hesitate to contact us if you have any further questions.
Sincerely yours,
The authors
Responses to the reviewer´s suggestions for the manuscript: Technical and Environmental Feasibility Study of the Co-Production of Crude Oil and Electrical Energy from Geothermal Resources: First Field Trial in Colombia
Reviewer 1.
Comment: I think that the paper should be improved. The introduction has been reduced, but it is still too long. The exergy analysis is incomplete. You evaluate the exergy resource, but the exergy efficiency of the process is not taken into account. The total exergy could be poor with a resource with high exergy if the process is inefficient from the exergy point of view.
Response: We thank the reviewer for her/his recommendations to improve the article. These have been considered, and we believe is now suitable for publication in Processes.
Accordingly, text was deleted in Lines 55-62, 66-68, 70-72, 86-87, 104-106. Nevertheless, the rest of the Introduction was maintained to highlight the novelty of the study.
Regarding the exergy efficiency, the following was included in Section 3.2.:
“Another parameter to evaluate the performance of the technology is the exergy effi-ciency. This parameter compares the amount of exergy employed regarding the exergy available at the beginning of the process, as shown in Equation 6:
|
|
(6) |
where Wava is the exergy available at the beginning of the process (kW).
…
Table 3. Monitoring parameters of the energy production in the ORC system.
|
Time |
Water flow (kg s-1) |
Thermal power (kWt) |
|
|
|
5:44 |
35.8 |
1803 |
4% |
22% |
|
9:02 |
30.7 |
1548 |
4% |
20% |
|
10:00 |
30.7 |
1548 |
3% |
20% |
|
11:00 |
30.7 |
1548 |
3% |
20% |
|
12:00 |
30.7 |
1548 |
3% |
18% |
|
13:02 |
35.1 |
1767 |
3% |
17% |
|
14:00 |
35.1 |
1767 |
3% |
18% |
|
15:00 |
35.1 |
1767 |
3% |
18% |
|
16:00 |
35.1 |
1767 |
3% |
19% |
|
17:00 |
35.1 |
1767 |
3% |
20% |
|
18:00 |
32.9 |
1662 |
4% |
26% |
|
19:00 |
26.4 |
1332 |
5% |
24% |
|
20:00 |
31.8 |
1603 |
4% |
25% |
|
21:00 |
30.5 |
1537 |
5% |
24% |
|
22:00 |
31.6 |
1594 |
5% |
25% |
|
23:00 |
31.4 |
1581 |
5% |
24% |
|
0:00 |
32.7 |
1649 |
5% |
26% |
|
1:00 |
29.7 |
1496 |
5% |
26% |
|
2:00 |
30.0 |
1511 |
5% |
26% |
|
3:00 |
31.3 |
1575 |
5% |
25% |
|
4:00 |
31.4 |
1584 |
5% |
31% |
|
5:00 |
26.2 |
1321 |
6% |
22% |
…
“In addition, as seen in Table 3, low exergy efficiency values are observed between 12:00 and 17:00, which are the times of the highest ambient temperature. This can be explained due to the influence that ambient temperature has on the condensation of the working fluid inside the ORC, where the ambient air is used as a cooling substance. Hence, high ambient temperatures do not allow a complete condensation of the working fluid. A higher temperature difference between the source and the sink leads to a better performance of the ORC system [78,79].
On the other hand, the production system has an average exergy efficiency of 23%, indicating that only that percentage is transformed into produced power. The amount that is not usable in power generation is exergy wasted as residual heat and exergy de-stroyed, suggesting that the proposed process can be optimized through improvements in the working fluid or the ORC components [64,79].”
Author Response File: Author Response.pdf
Reviewer 2 Report
The authors respond to all my questions. I recomend the aproval of the manuscript
Author Response
We thank the reviewer for her/his recommendation for approval of the manuscript. Her/his suggestions helped improve the document for publication.
Reviewer 3 Report
The paper is acceptable in this form.
Author Response
We thank the reviewer for her/his recommendation for approval of the manuscript. Her/his suggestions helped improve the document for publication.
Round 3
Reviewer 1 Report
According to the reply and the comments of the other reviewer, I don' have to add anything more. I will propose to accept the paper
