grammar check

ENS5145 Engineering Honours Thesis 1

Proposal and Risk Assessment Report

Enhanced Heavy Oil Recovery Using CO2 Huff-n-Puff Process

AL AZWAR AL BATTASHI

Student # 10492966

28 August 2020

Supervisor: Dr Ahmed Yaseri

Ethics Declaration Checklist (to be completed by student)
Does this project involve the use of:	YES/NO
(a) Human participants,	NO
(b) Previously collected confidential data,	NO
(c) Animals for scientific purposes?	NO
If ‘YES’ to any of the above, then the proposal will not be approved, and you will not be allowed to proceed with this project. By submitting this report through the unit website for assessment, you certify that the information provided above is true and correct.

Abstract

This paper is a description of the use of the CO2 Huff-n-Puff process in the recovery of heavy oil. Among all the methods of CO2 based enhanced oil recovery, CO2 Huff ‘n’ Puff method is the best applicable recovery method. This paper will review and discuss the objective of this method. Also, it will review some experimental studies to investigate and determine the suitable properties for CO2 huff ‘n’ puff process as well as addressing some challenges that could face this method.

1. Introduction

1.1. Motivation

The growth in population and industrial development across the world is a great contributor to the global spike in energy demand over the past few decades. This, coupled with the fact that most renewable energy technologies are not yet fully developed to satisfy the energy needs of the planet, has increased the demand for oil and natural gas. This has increased pressure on the extraction and supply of hydrocarbon resources in the world, leaving a lot of oil crises in its wake. Heavy oil reservoirs are some of the most challenging extraction sites for modern engineers, but they have been forced to find solutions to this challenge to increase the supply of oil and address the global energy problem. This has led to various technological prospects such as the CO2 Huff-n-Puff process that is discussed in this study. Although this is currently the most used approach in heavy oil recovery, more techniques are expected to spring up as more research is conducted in the field. This is driven by the current drop in production from conventional reservoirs and the fact that heavy oil reserves have been proven to hold up to three times more hydrocarbon resources than regular reserves. This technique is among those that will be credited for an increase in oil and gas in the world market in the coming years.

The Huff-n-Puff process described in this project, which involves the injection of CO2 in heavy oil reserves, is not new to the oil arena as it has been in extensive use for recovery of oil in conventional reserves. The process is also known as the cyclic injection of CO2 and it consists of three main stages namely;

(i) The injection stage- CO2 is injected into the reservoir in a pressurized form. The bottom part of the reservoir is targeted so that pressure from the incoming gas forces the oil upwards for easier extraction.

(ii) The soaking stage- this stage involves isolation of the well for some time to afford it time to settle with the new gas input.

(iii) The production stage- involves the extraction of oil and gas through mechanisms that involve the use of pumps and other forms of machinery.

The oil recovery factor and condition of miscibility are considered the most important factors in heavy oil recovery. The recovery factor is a quantifier that is obtained by comparing the volume of oil recovered and the volume and pressure of gas that is injected into the well. Miscibility is dependent on various factors such as the composition of oil in the reservoir, the swelling coefficient of the reservoir, the overall solubility of reservoir contents, diffusion processes, and reservoir pressure. The gas must always be above the minimum miscibility pressure (MMP) of the reservoir during the injection. The MMP is the pressure at which the gas is completely soluble in the liquid phase. This condition also has a definite temperature and gas composition that have to be known before the operation. The Huff-n-Puff tests conducted in this study are aimed at evaluating the efficiency of CO2 injection in the recovery of heavy oil. This is done over the allowed pressure range (a total of five pressure points). This study discusses a total of forty Huff-n-Puff tests based on the data of Shilov et al. (2019). Data obtained is used to determine the mixing zone of the oil’s light fractions, change in the composition of the oil, and the and the drop-in permeability.

1.2. Objectives

The primary objective of this study is to evaluate the use of the CO2 Huff-n-Puff process to enhance the recovery of oil and gas from heavy oil reservoirs.

The secondary objectives include;

(i) To determine the effect of the CO2 Huff-n-Puff system on the oil recovery factor.

(ii) To determine key reservoir parameters influencing the effectiveness of the CO2 Huff-n-Puff method.

1.3. Significance

The Huff-n-Puff tests conducted in this study are aimed at establishing the applicability and efficiency of CO2 in the process. In addition to this, the tests also aim to determine the effects of the process on miscibility and other key oil and gas properties that affect its extraction. Heavy oil reserves have more limitations to oil flow as compared to other reserves, and this means they have different responses to conventional extraction methods such as gas-injection and flooding. The recovery mechanisms of heavy oil reserves must be understood to determine the most effective recovery techniques. Tests have been conducted in the area from as early as the eighties, but little success has been achieved since then. The Huff-n-Puff process is the newest technique that shows promise, but a precise methodology is yet to be developed.

2. Proposed Approach

This project is a literature review only, not involving any use of a laboratory. All the experimental studies and data in this project are from other papers and online resources. This project is broken into five tasks.

The review starts with “Resources and recovery method of the heavy oil”. This task is aimed to discuss and compare the best method for heavy oil recovery. (PetroWiki, 2016) (Zhou et al., 2018).

The second task of the review is “The CO2 huff ‘n’ puff process and mechanism”. The process is also known as the cyclic injection of CO2 and it consists of three main stages namely; injection stage, the soaking stage and production stage (Zhou et al.,2018). This task has four sub-tasks. firstly, the paper will look at “Foamy oil” which can provide a greater oil production (Monger et al., 1991). Secondly, the literature review will discuss a very significant mechanism in the process of Huff ‘n’ Puff which is “Viscosity reduction”. Here, the review will show the reasons for viscosity reduction when injecting a CO2 into the heavy oil (Jeffries-Harris and Coppel, 1969) and the result of this reduction (Zhou et al., 2018). An important phenomenon will be discussed as well in the literature review which is “Oil swelling”. This paper will show the importance of this mechanism to enhanced oil recovery of Huff ‘n’ puff process (Yang and Gu, 2006). Lastly, the paper will look at a very important parameters which is “Diffusion coefficient”. In this section, the paper will discuss the impact of Diffusion coefficient on the properties of the heavy oil-CO2 system (Huang et al., 2016).

Furthermore, “Experimental studies” is the fourth task in the literature review. The experiments and data of this task are from other sources and research (Huang et al., 2017; Zhou et al., 2018). In this task, the paper will show an investigation of the fluid properties in the process and to determine the suitable properties for CO2 huff ‘n’ puff process.

The fifth task in the literature review is “Numerical and mathematical studies”. The paper will focus on numerical simulation that have been made by other people and published on their research. The paper will show and discuss the results of these simulation (Ekhlasjoo et al., 2014; Luo et al., 2005).

Finally, the paper will show “Challenges of CO2 Huff ‘n’ Puff process” and discuss the main issues of CO2 Huff ‘n’ Puff process in heavy oil Recovery (Al-Maamari and Buckley, 2000; Hashemi-Kiasari et al., 2014; Zhou et al., 2018).

3. Timeline

The timeline of this project is illustrated utilizing a Gantt chart as shown in attachment 1.1 and 1.2. According to the chart, by week 12 of semester one 2021, all project work must be completed and will be presented on week 13.

According to the Gantt charts illustrated below, the first activity of the project is the selection of an appropriate dissertation topic. This has already been done and the selected topic is “Enhanced Heavy Oil Recovery using the CO2 Huff-n-Puff Process.” The subsequent parts that have been done previously include the draft of aims and objectives, submission of the aims and objectives and objectives for vetting, and the provision of this proposal which the current stage. The literature review has been broken into five main tasks and each task has sub-task as clearly shown in the given charts. The scheduled deadline in the milestone has been set by ECU during the semester, and the tasks deadline set by me.

At this stage, it is very hard to make a statement regarding the timeline being realistic.

4. Risk Assessment

Considering the fact that this project is a literature review, there are some risk assessment associated with this project and will be categorised into the following categories:

· Supervisor (SUP):

· Lack of consistent communication between the students and the project supervisor- this is a low probability and medium effect risk on the project. Doing this project off-campus is very hard and stressful as E-mail is a slow method to contact with the supervisor. Lack of constant communication may result in the students doing the wrong thing without their knowledge or be unable to seek help if stuck.

· Computer (CMP):

· Loss of digital data- this a medium probability and medium effect risk. The work of this project is on Computer. As a result, there is always a risk of the drive crashing due to a virus attack or system overload, and this would result in a loss of files that are paramount to this project. This is avoided by ensuring that digital files are always stored in a cloud-based system such as the Google Drive so that they may always be recovered.

· Personnel (PER):

· Illness- This would affect the rate of work on the project and is likely to fall behind schedule. This is the unprecedented risk that is most likely to occur.

· Overworking and lack of sufficient rest- This would result in the student undergoing work-related stress and may also result in sickness. Managing the time probably and well-sleeping will reduce the workload.

· Ergonomic (ERG):

· Bad sitting position- this will affect the rate of work on the project as well and reduce the productivity. Insure having an adjustable chair with movable back seat position.

· Eye strain- too much time spent looking at the computer screen may cause eye strain and headache and that will affect the efficiency and productivity of the project. Maintain correct Eye-level distance from the screen.

· Environment (ENV):

· Environmental pollution- this is a high probability and high impact risk factor as the possibility of oil spills and ecological damage is always present. The Huff-n-Puff process must be implemented in a safe way that ensures that surrounding ecologies, especially the underground water system and ecosystems, remain unharmed.

· Carbon poisoning- Inhalation of excessive amounts of CO2 would result in the restriction of oxygen levels in the body and consequent collapse.

5. Progress to Date

The current stage of this project is the drafting and submission of the proposal. The topic has already been selected and the set of aims and objectives has already been submitted and approved. The timeline for the tasks has been set and most of the sources have been found starting to write the literature review.

6. Conclusion

This project involves the use of a CO2 Huff-n-Puff system to enhance the recovery of oil and gas from heavy oil reservoirs. The proposed methodology involves a three-stage method in which the CO2 Huff-n-Puff system is used to recover oil from a reservoir. The main objective of this method is to evaluate the use of the CO2 Huff-n-Puff process to enhance the recovery of oil and gas from heavy oil reservoirs. The system and data used are based on the work of Shilov et al. (2019). To prove the efficiency of the system, the effect of the system on the oil recovery factor of the two reservoirs is investigated, and it is proven to increase it by 13%. The literature review has been broken into five main tasks and to be done within two semesters.

7. References

Al-Maamari, R.S.H., Buckley, J.S., 2000. Asphaltene precipitation and alteration of wetting: can wettability change during oil production?, in: SPE/DOE Improved Oil Recovery Symposium. Tulsa, Oklahoma. https://doi.org/10.2118/59292-MS

Butler, R. (1998, July 1). SAGD Comes of AGE! Petroleum Society of Canada. doi:10.2118/98-07-DA

Ekhlasjoo, I., Vosoughi, M., Shadizadeh, S.R., Kharrat, R., Ghazanfari, M.H., 2014. An experimental and simulation study of heavy oil recovery by the liquid CO2 huff and puff method. Energy Sources, Part A Recover. Util. Environ. Eff. 36, 2587–2594. https://doi.org/10.1080/15567036.2011.569834

Huang, Y., Zhou, X., Zeng, F., 2016. Comparison study of two different methods on the localised Enkf on SAGD processes, in: International Petroleum Technology Conference. Bangkok, Thailand. https://doi.org/10.2523/IPTC-18907-MS

Huang, T., Zhou, X., Yang, H., Liao, G., Zeng, F., 2017. CO2 flooding strategy to enhance heavy oil recovery. Petroleum 3, 68–78. https://doi.org/10.1016/j.petlm.2016.11.005

Jeffries-Harris, M.J., Coppel, C., 1969. Solvent stimulation in low gravity oil reservoirs. J. Pet. Technol. 21, 167–175. https://doi.org/10.2118/2158-PA

Luo, R., Cheng, L., Peng, J., 2005. Feasibility study of CO2 injection for heavy oil reservoir after cyclic steam stimulation: Liaohe oil field test, in: Proceedings of SPE/PS-CIM/CHOA International Thermal Operations and Heavy Oil Symposium. Calgary, Alberta, Canada. https://doi.org/10.2523/97462-MS

Monger, T.G., Ramos, J.C., Thomas, J., 1991. Light oil recovery from cyclic CO2 injection: influence of low pressures, impure CO2, and reservoir gas. SPE Reserv. Eng. 6, 25–32. https://doi.org/10.2118/18084-PA

Shilov, E., Cheremisin, A., Maksakov, K., & Kharlanov, S., 2019. Huff-n-Puff Experimental Studies of CO2 with Heavy Oil. [Online] Available at: <https://www.mdpi.com/1996-1073/12/22/4308/pdf> [Accessed August 20, 2020]

Tang, Y., Su, Z., He, J., & Yang, F., 2016. Numerical Simulation and Optimization of Enhanced

Oil Recovery by the In Situ Generated CO2 Huff-n-Puss Process with Compound Surfactant. Journal of Chemistry, vol. 2016, ID 6731848, DOI: 10.1155/2016/6731848

Yang, C., Gu, Y., 2006. Diffusion coefficients and oil swelling factors of carbon dioxide, methane, ethane, propane, and their mixtures in heavy oil. Fluid Phase Equilib. 243, 64–73. https://doi.org/10.1016/j.fluid.2006.02.020

Zhou, X., Yuan, Q., Rui, Z., …, & Zeng, F., 2019. Feasibility study of CO2 huff ‘n’ puff process to enhance heavy oil recovery via long core experiments. Applied Energy, vol. 236, iss. 15, pp. 526-539

Zhou, X., Peng, X., Zeng, F., & Zhang, L. 2018. A critical review of the CO2 huff ‘n’ puff process for enhanced heavy oil recovery (Vol. 215, pp. 813-824). https://doi.org/10.1016/j.fuel.2017.11.092

Page 1 of 5

Page 2 of 5

Attachment 1.1 – Timeline Chart

Attachment 1.2 – Timeline Chart

Attachment 2 – Risk Assessment Matrix