Effect of CO<sub>2</sub> Huff and Puff Rounds on Crude Oil Properties

Shi, Qionglin; Gong, Sha; Qin, Xiaoping

doi:https://doi.org/10.1155/2023/1008075

Journal of Chemistry

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Abstract Introduction Results and Discussion Conclusions Data Availability Conflicts of Interest Acknowledgments References Copyright Related Articles

Research Article | Open Access

Volume 2023 | Article ID 1008075 | https://doi.org/10.1155/2023/1008075

Effect of CO₂ Huff and Puff Rounds on Crude Oil Properties

Qionglin Shi,¹Sha Gong,¹and Xiaoping Qin²

Academic Editor: Haci Baykara

Received13 Nov 2022

Revised01 Apr 2023

Accepted20 Apr 2023

Published02 May 2023

Abstract

In view of the deterioration of oil well liquid supply capacity and oil increase effect after multiple rounds of carbon dioxide (CO₂) huff and puff, according to the actual conditions of the Ng12 reservoir in the XA oilfield, an indoor physical simulation experimental model was established. The experimental parameters were determined, five rounds of CO₂ huff and puff experiments were carried out, and the crude oil produced in the water flooding stage and different rounds of CO₂ huff and puff were collected. The effects of CO₂ huff and puff rounds on crude oil viscosity, density, composition, paraffin content, and gum asphaltene content were studied. The results show that with the increase in CO₂ huff and puff rounds, the viscosity and density of produced crude oil decrease. The content of light component (C₂∼C₆) and intermediate component (C₇∼C₁₀) increased, while the content of heavy component (C₁₁₊) decreased. CO₂ has the strongest extraction effect on light components and the weakest extraction effect on heavy components. At the same time, the content of paraffin and gum asphaltene in the produced crude oil is reduced. For oil wells with multiple rounds of CO₂ huff and puff, colloidal asphaltene precipitation inhibitor and scavenger should be considered to reduce the impact of colloidal asphaltene on formation permeability and liquid supply capacity.

1. Introduction

Carbon dioxide (CO₂) huff and puff is a very important enhanced oil recovery (EOR) method for heavy oil reservoirs developed by natural energy [1–4]. Compared with other huff and puff media (such as nitrogen, air, and active water), CO₂ is easily soluble in crude oil, which can reduce crude oil viscosity, extract light components, reduce interfacial tension, and supplement formation energy [5–7].

The Ritchie oilfield in Arkansas [8], Wilmington oilfield in California [9], and Appalachian Basin-Big Sinking oilfield in Kentucky [10] have all carried out the field application of CO₂ huff and puff. Through CO₂ huff and puff technology, the single well production of Bail Raman heavy oilfield in Turkey has been greatly increased, and the average production has been increased by 4 times [11]. China’s Changqing Oilfield, Jilin Oilfield, and Jidong Oilfield have carried out a large number of field applications of CO₂ huff and puff and achieved good application results [12–15]. The field application results show that with the increase in CO₂ huff and puff rounds, the liquid supply capacity and oil increase effect of oil wells become worse. Scholars try to find out the reasons for the poor effect of multiple rounds of CO₂ huff and puff [16].

At present, scholars have carried out in-depth research on the oil increase mechanism of CO₂ huff and puff and field implementation parameters (such as injection volume, soaking time, and production parameters) [17, 18]. Through nuclear magnetic resonance (NMR), the distribution of residual oil after supercritical CO₂ huff and puff of low permeability core is studied [19]. In addition, the oil recovery characteristics of the Huff-n-Puff process of carbonated water in tight cores have been studied under reservoir conditions [20]. Tang et al. [21] studies the factors affecting the effect of CO₂ huff and puff (such as injection volume, soak time, huff and puff rounds, and well type).

In terms of improving the oil increasing effect of multiple rounds of CO₂ huff and puff, the current common practice is to continuously increase the injection amount of CO₂, which will significantly increase costs. In addition, the use of appropriate chemicals (such as surfactant, gel plugging agent, etc.) to assist CO₂ huff and puff is also a method to improve the oil increase effect. Surfactants can reduce the interfacial tension between crude oil and formation water, thereby improving the fluidity of the remaining oil [22, 23]. The gel plugging agent can plug the large pores existing in the formation and prevent carbon dioxide from channeling along the large pores, thus improving the utilization efficiency of carbon dioxide [24].

In addition to factors such as the amount of carbon dioxide used and the presence of large pores in the formation, the properties of crude oil can also affect the oil increase the effect of CO₂ huff and puff. However, there are few reports on the indoor physical simulation experiments of CO₂ huff and puff and the effects of multiple rounds of CO₂ huff and puff on the properties of crude oil. So five rounds of CO₂ huff and puff experiments were carried out, and the crude oil produced in the water flooding stage and different rounds of CO₂ huff and puff were collected. The impact of CO₂ huff and puff rounds on crude oil performance has been studied, and the corresponding technical countermeasures have been provided, which can provide a reference for improving the oil increasing effect of multiple rounds of CO₂ huff and puff.

2. Experimental Section

2.1. Materials

The water used in the experiment is the formation water of the Ng12 reservoir in the XA oilfield. The crude oil used in the experiment is the crude oil of well XA119-7. The sand used in the experiment is the formation sand of the Ng12 reservoir in the XA oilfield. The purity of liquid CO₂ used in the experiment is 99.99%. The minimum miscible pressure of CO₂ and crude oil is 27.3 MPa. The parameters of the crude oil of well XA119-7 are shown in Table 1, and the ions of formation water are shown in Table 2.

2.2. Instrument

The 2PB-1040IV advection pump was purchased from Beijing Xingda Technology Development Co., Ltd; the JSJ-540AD electric constant temperature blast drying oven was purchased from Chengdu Shengjie Technology Co., Ltd; piston type intermediate vessel, sand filling model (diameter 15 cm, length 80 cm, Figure 1), and pressure acquisition system, back pressure valve were purchased from Hai’an Petroleum Scientific Research Instrument Co., Ltd; the DV-III viscometer was purchased from Brookfile, USA; the BSY-109B density tester was purchased from Dalian Beigang Petroleum Instrument Co., Ltd; gas chromatograph was purchased from American Agilent company; and the asphaltene tester and wax content tester were purchased from Shanghai Rongjida Instrument Technology Co., Ltd.

2.3. Indoor Physical Simulation Experiment of CO₂ Huff and Puff

2.3.1. Experimental Parameters

Based on the principle of similarity and equivalence, the actual reservoir parameters were converted into indoor physical simulation experiment parameters, and the injection amount of CO₂ in indoor experiment was calculated. The relevant experimental parameters are shown in Table 3.

2.3.2. Experimental Flowchart

The flowchart of indoor simulation experiment of multiple rounds of CO₂ huff and puff is shown in Figure 2. Relevant instruments and equipment were connected according to Figure 2.

2.3.3. Experimental Procedures

(1) Experimental Model Preparation. Wash and dry the formation sand of the Ng12 reservoir in the XA oilfield, and fill the sand filling model with this dry formation sand. The advection pump was used to inject formation water into the sand filling model until no gas was discharged. Inject XA119-7 well crude oil into the sand filling model at the injection rates of 2 ml/min until there was no water at the outlet end. Close the valves at both ends of the sand filling model and place it at 65°C for 10 days. Inject formation water at the injection rate of 10 ml/min, record the water and oil output every 10 minutes until the water content reached 99%, and collect the produced crude oil.

(2) CO₂ Huff and Puff. Gas injection: close the inlet end of the sand filling model and inject CO₂ with a volume of 1 L and a pressure of 1.0 MPa into the sand filling model from the outlet end.

Stewing: close the valves at both ends of the sand filling model and place it at 65°C for 20 days.

Production: connect the experimental process, open the outlet end, inject formation water at the injection rate of 10 ml/min from the injection end, and record the water and oil output every 10 minutes until the water content reached 99%, and the first round of CO₂ huff and puff was completed.

After completing the first round of CO₂ huff and puff, continue the next round of CO₂ huff and puff, and collect the crude oil produced by each round of CO₂ huff and puff.

Parallel experiments (1# and 2#) are conducted, and the crude oil obtained from the same huff and puff rounds in both experiments is mixed evenly and used for property analysis.

The pressures after the first to fifth rounds of carbon dioxide injection are 5.22 MPa, 5.76 MPa, 6.18 MPa, 6.57 MPa, and 7.02 MPa, respectively. This is because as the number of rounds increases, the crude oil in the sand filling model is continuously produced, resulting in a decrease in the corresponding oil saturation, which will lead to a decrease in the amount of carbon dioxide dissolved in the crude oil.

2.4. Crude Oil Property Analysis

2.4.1. Determination of Crude Oil Viscosity

The DV-III viscometer was used to measure the viscosity of crude oil produced in the water flooding stage and different CO₂ huff and puff rounds. The test was carried out at 65°C, and the shear rate was 7.34 s⁻¹. After the test, the curve of crude oil viscosity changing with CO₂ huff and puff rounds was drawn.

2.4.2. Determination of Crude Oil Density

The BSY-109B density tester was used to measure the density of crude oil produced in the water flooding stage and different CO₂ huff and puff rounds. The test temperature was 65°C. After the measurement, the curve of crude oil density with CO₂ huff and puff rounds was drawn.

2.4.3. Determination of Crude Oil Composition

The determination steps of crude oil components are as follows:(1)Weigh 30∼50 mg crude oil sample, dissolve it with 30 ml n-hexane, precipitate asphaltene overnight, and concentrate the solution to 1∼2 ml.(2)Transfer the concentrated solution to the chromatographic column containing 4 mg silica gel and 2 mg alumina, elute the saturated hydrocarbon fraction with 20 ml n-hexane for 4 times, and transfer the saturated hydrocarbon solution to the small mouth sample bottle for standby after concentration at 40°C.(3)Start the gas chromatograph and control system, input the analysis parameters, ignite the hydrogen flame ionization detector, and check the stability of the chromatographic baseline during the temperature programmed process.(4)Suck the sample with a microsyringe into the vaporization chamber of the gas chromatograph, start the temperature rise program, and use the computer (or chromatographic processing system) for data acquisition and processing.

2.4.4. Determination of Paraffin, Gum, and Asphaltene Content

The content of wax, gum, and asphaltene in crude oil produced in the water flooding stage and crude oil produced in different CO₂ huff and puff rounds was determined according to the petroleum industry standard (SY/T 7550-2004 Determination Method of Wax, Gum, and Asphaltene Content in Crude Oil).

3. Results and Discussion

3.1. Effect of CO₂ Huff and Puff Rounds on Enhanced Oil Recovery

The effect of CO₂ huff and puff rounds on enhanced oil recovery is shown in Table 4. The average value of oil recovery factor before CO₂ huff and puff is 26.8%. Through the first round of CO₂ huff and puff, the average value of oil recovery factor is increased by 7.1%. Then, with the increase in CO₂ huff and puff rounds, the extent of oil recovery factor is reduced. Through the last round of CO₂ huff and puff, the average value of oil recovery factor is increased by 4.1%. The reason for this result is that with the increase in CO₂ huff and puff rounds, the saturation of porous media in the sand filling model decreases continuously.

3.2. Effect of CO₂ Huff and Puff Rounds on Crude Oil Viscosity

The viscosity of crude oil produced in water flooding stage and crude oil produced in different rounds of CO₂ huff and puff was measured with viscometer, and the relationship curve between viscosity and CO₂ huff and puff rounds was drawn. The results are shown in Figure 3.

It can be seen from Figure 3 that with the increase in CO₂ huff and puff rounds, the viscosity of produced crude oil gradually decreases. The viscosity of crude oil produced in the water flooding stage is 112.5 MPa·s. The viscosity of crude oil produced in the first round of CO₂ huff and puff is 104.6 MPa·s. The viscosity of crude oil produced in the fifth round of CO₂ huff and puff is 86.9 MPa·s. This is because CO₂ can extract crude oil, which can continuously extract light components and intermediate components in crude oil, so that the viscosity of the produced crude oil is continuously reduced.

3.3. Effect of CO₂ Huff and Puff Rounds on Crude Oil Density

The density of the crude oil produced in the water flooding stage and the crude oil produced in different rounds of CO₂ huff and puff was measured by the density meter, and the relationship curve between the density and the rounds of CO₂ huff and puff was drawn, as shown in Figure 4.

It can be seen from Figure 4 that the density of crude oil produced gradually decreases with the increase in CO₂ huff and puff rounds. The density of crude oil produced in the water flooding stage is 0.935 g/cm⁻³, the density of crude oil produced in the first round of CO₂ huff and puff is 0.912 g/cm⁻³, and the density of crude oil produced in the fifth round of CO₂ huff and puff is 0.861 g/cm⁻³. The experimental results show that CO₂ can continuously extract the light components and intermediate components in the crude oil, and more heavy components are left in the sand filling model, which makes the crude oil lighter and the density lower round by round.

3.4. Effect of CO₂ Huff and Puff Rounds on Crude Oil Components

The components of crude oil produced in the water flooding stage and crude oil produced in different rounds of CO₂ huff and puff were measured by gas chromatograph. The results are shown in Figures 5–7.

The experimental results show that with the increase in CO₂ huff and puff rounds, the content of light components (C₂∼C₆) and intermediate components (C₇∼C₁₀) in the produced crude oil gradually increases, while the content of heavy components (C₁₁₊) gradually decreases. The contents of light components, intermediate components, and heavy components of crude oil produced in the water flooding stage are 9.0%, 2.6%, and 88.4%, respectively. The contents of light components, intermediate components, and heavy components of crude oil produced in the fifth round of CO₂ huff and puff are 22.1%, 2.1%, and 72.8%, respectively. The experimental results show that CO₂ has the strongest extraction effect on the light components of crude oil, the second on the intermediate components of crude oil, and the weakest on the heavy components of crude oil.

3.5. Effect of CO₂ Huff and Puff Rounds on the Contents of Paraffin, Gum, and Asphaltene

The contents of paraffin and gum asphaltene in crude oil produced in the water flooding stage and crude oil produced in different rounds of CO₂ huff and puff were measured, as shown in Figures 8 and 9, respectively.

The experimental results show that the content of paraffin and gum asphaltene in the produced crude oil decreases gradually with the increase in huff and puff times. The paraffin and gum asphaltene contents of crude oil produced in the water flooding stage are 30.6% and 3.1%, respectively. The paraffin and gum asphaltene contents of crude oil produced in the fifth round of CO₂ huff and puff are 21.5% and 2.0%, respectively. This is because after the light components in the sand filling model are recovered, the saturation of paraffin and gum asphaltene increases continuously, precipitation and flocculation occur, which makes it more difficult to recover paraffin and gum asphaltene, and the content of paraffin and gum asphaltene in the recovered crude oil decreases continuously.

4. Conclusions and Suggestions

(1)With the increase in CO₂ huff and puff rounds, the viscosity and density of produced crude oil decrease. The content of light components (C₂∼C₆) and intermediate components (C₇∼C₁₀) increased, while the content of heavy components (C₁₁₊) decreased. CO₂ has the strongest extraction effect on light components and the weakest extraction effect on heavy components. At the same time, the content of paraffin and gum asphaltene in the produced crude oil is reduced.(2)With the increase in CO₂ huff and puff rounds, a large number of light components are extracted and recovered, and the proportion of gum asphaltene in the remaining oil in the formation increases, which affects the oil increase effect of multiple rounds of CO₂ huff and puff. Therefore, it is suggested to screen and apply suitable gum asphaltene precipitation inhibitors and scavengers according to the target reservoir conditions in the subsequent CO₂ huff and puff process so as to reduce the impact of gum asphaltene on formation permeability.

Data Availability

All basic data can be found in the article.

Conflicts of Interest

The author declares that he has no conflicts of interest.

Acknowledgments

This work was supported by the Talent Introduction Founds of Sichuan University of Science and Engineering (grant no. 2020RC05), the Key Science and Technology Plan Projects of Zigong City (grant no. 2020YGJC09), and the project of PetroChina Jidong Oilfield Company (grant no. 2020-JS-50814).

References

S. E. Cudjoe, R. Barati Ghahfarokhi, R. H. Goldstein et al., “An integrated workflow to characterize lower Eagle Ford shale for hydrocarbon gas huff-n-puff simulation,” Fuel, vol. 289, Article ID 119854, 2021.
View at: Publisher Site | Google Scholar
G. Fan, J. Xu, M. Li, T. Wei, and S. M. M. Nassabeh, “Implications of hot chemical–thermal enhanced oil recovery technique after water flooding in shale reservoirs,” Energy Reports, vol. 6, pp. 3088–3093, 2020.
View at: Publisher Site | Google Scholar
B. Wei, M. Zhong, K. Gao et al., “Oil recovery and compositional change of CO₂ huff-n-puff and continuous injection modes in a variety of dual-permeability tight matrix-fracture models,” Fuel, vol. 276, Article ID 117939, 2020.
View at: Publisher Site | Google Scholar
A. Junira, K. Sepehrnoori, S. Biancardi, R. Ambrose, W. Yu, and R. Ganjdanesh, “Optimization of huff-n-puff field gas enhanced oil recovery through a vertical well with multiple fractures in a low-permeability shale–sand–carbonate reservoir,” Energy and Fuels, vol. 34, no. 11, pp. 13822–13836, 2020.
View at: Publisher Site | Google Scholar
K. Yang, S. Li, K. Zhang, and Y. Wang, “Synergy of hydrophilic nanoparticle and nonionic surfactant on stabilization of carbon dioxide-in-brine foams at elevated temperatures and extreme salinities,” Fuel, vol. 288, no. 3, Article ID 119624, 2021.
View at: Publisher Site | Google Scholar
H. Hamdi, C. R. Clarkson, and A. Esmail, “Optimizing the huff-n-puff gas injection performance in shale reservoirs considering the uncertainty: a duvernay shale example,” SPE Reservoir Evaluation and Engineering, vol. 24, pp. 1–19, 2020.
View at: Google Scholar
Y. Wang, Q. Shang, L. Zhou, and Z. Jiao, “Utilizing macroscopic areal permeability heterogeneity to enhance the effect of CO₂ flooding in tight sandstone reservoirs in the Ordos Basin,” Journal of Petroleum Science and Engineering, vol. 196, Article ID 107633, 2021.
View at: Publisher Site | Google Scholar
P. Mahzari, T. M. Mitchell, and A. P. Jones, “Novel laboratory investigation of huff-n-puff gas injection for shale oils under realistic reservoir conditions,” Fuel, vol. 285, Article ID 118950, 2020.
View at: Google Scholar
X. Jia, M. Luo, and H. Pu, “Numerical simulation of CO₂ huff-and-puff process in a hydraulically fractured horizontal well in a tight oil reservoir,” The Leading Edge, vol. 39, no. 1, pp. 16–21, 2020.
View at: Publisher Site | Google Scholar
S. Wang, X. Yao, Q. Feng et al., “Molecular insights into carbon dioxide enhanced multi-component shale gas recovery and its sequestration in realistic kerogen,” Chemical Engineering Journal, vol. 425, Article ID 130292, 2021.
View at: Publisher Site | Google Scholar
A. Abedini and F. Torabi, “On the CO₂ storage potential of cyclic CO₂ injection process for enhanced oil recovery,” Fuel, vol. 124, no. 15, pp. 14–27, 2014.
View at: Publisher Site | Google Scholar
W. Pu, B. Wei, F. Jin et al., “Experimental investigation of CO₂ huff-n-puff process for enhancing oil recovery in tight reservoirs,” Chemical Engineering Research and Design, vol. 111, pp. 269–276, 2016.
View at: Publisher Site | Google Scholar
S. Li, C. Lu, M. Wu, Z. Hu, Z. Li, and Z. Wang, “New insight into CO₂ huff-n-puff process for extraheavy oil recovery via viscosity reducer agents: an experimental study,” Journal of CO₂ Utilization, vol. 42, Article ID 101312, 2020.
View at: Publisher Site | Google Scholar
A. M. Hassan, M. Ayoub, M. Eissa, H. Bruining, and P. Zitha, “Study of surface complexation modeling on a novel hybrid enhanced oil recovery (EOR) method; smart-water assisted foam-flooding,” Journal of Petroleum Science and Engineering, vol. 195, Article ID 107563, 2020.
View at: Publisher Site | Google Scholar
Y. Zhao, G. Fan, Y. Li, X. Zhang, H. Chen, and H. Sun, “Research for reducing minimum miscible pressure of crude oil and carbon dioxide and miscible flooding experiment by injecting citric acid isopentyl ester,” Arabian Journal of Chemistry, vol. 13, no. 12, pp. 9207–9215, 2020.
View at: Publisher Site | Google Scholar
L. J. Hosking and H. R. Thomas, “Dual porosity modelling of coal core flooding experiments with carbon dioxide,” Computers and Geotechnics, vol. 121, Article ID 103454, 2020.
View at: Publisher Site | Google Scholar
G. Fan, Y. Zhao, Y. Li, X. Zhang, and H. Chen, “Research for reducing the Minimum Miscible Pressure of crude oil and carbon dioxide by injecting citric acid isobutyl ester,” Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, vol. 76, no. 17, p. 30, 2021.
View at: Publisher Site | Google Scholar
Y. Zhou, L. Ai, and M. Chen, “Taylor dispersion in nanopores during miscible CO₂ flooding: molecular dynamics study,” Industrial & Engineering Chemistry Research, vol. 59, no. 40, pp. 18203–18210, 2020.
View at: Publisher Site | Google Scholar
D. Du, C. Li, X. Song et al., “Experimental study on residue oil distribution after the supercritical CO₂ huff-n-puff process in low permeability cores with nuclear magnetic resonance (NMR),” Arabian Journal of Chemistry, vol. 14, no. 10, Article ID 103355, 2021.
View at: Publisher Site | Google Scholar
D. Du, Y. Shen, W. Lv et al., “Laboratory study on oil recovery characteristics of carbonated water huff-n-puff process in tight cores under reservoir condition,” Arabian Journal of Chemistry, vol. 14, no. 6, Article ID 103192, 2021.
View at: Publisher Site | Google Scholar
R. X. Tang, G. Y. Wu, and J. Chen, “Analysis and understanding of influencing factors of CO₂ huff and puff in complex fault block reservoirs in Subei Basin,” Sino-Global Energy, vol. 25, no. 12, pp. 32–38, 2020.
View at: Google Scholar
Y. Du and Z. Duan, “Research and application of the technology for microbial huff and puff in deep heavy oil reservoir,” Oilfield Chemistry, vol. 35, no. 3, pp. 499–502, 2018.
View at: Google Scholar
C. Chen and M. Gu, “Investigation of cyclic CO₂ huff-and-puff recovery in shale oil reservoirs using reservoir simulation and sensitivity analysis,” Fuel, vol. 188, pp. 102–111, 2017.
View at: Publisher Site | Google Scholar
H. W. Lu, Z. Y. Wang, T. Peng, J. Zheng, X. Yang, and X. Qin, “A novel method for improving recovery of heavy oil reservoirs with high water cut based on polymer gel-assisted CO₂ huff and puff,” Journal of Petroleum Exploration and Production Technology, vol. 11, no. 9, pp. 3533–3541, 2021.
View at: Publisher Site | Google Scholar

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Copyright © 2023 Qionglin Shi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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