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Australian Energy Producers Journal Australian Energy Producers Journal Society
Journal of Australian Energy Producers
RESEARCH ARTICLE (Non peer reviewed)

The study on mechanism of water–rock reaction in shale oil formation rich in alkaline minerals in Mahu Sag by using supercritical CO2

Yamin Wang A * and Kouqi Liu A
+ Author Affiliations
- Author Affiliations

A Institute of Energy, Peking University, Beijing, China.




Dr Yamin Wang is currently working as a postdoc at the Institute of Energy, Peking University. Her current research is related to the shale oil mobility analysis. Dr Yamin Wang is also interested in microscopic pore structure description, water-mineral reaction and CO2 storage feasibility analysis. She completed her PhD degree from the School of Minerals and Energy Resources Engineering, University of New South Wales (UNSW) in 2021 and her Master’s Degree from UNSW in 2017.



Dr Kouqi Liu is the assistant professor at the Institute of Energy, Peking University. His research interests include multi-scale rock mechanics (from nanoscale to macroscale), unconventional resources analysis (petrophysics and reservoir characterisation). He completed his PhD degree from University of North Dakota. Dr Liu was selected as top 2% scientist in the world in 2022.

* Correspondence to: yamin.wang@pku.edu.cn

Australian Energy Producers Journal 64 S294-S297 https://doi.org/10.1071/EP23092
Accepted: 19 March 2024  Published: 16 May 2024

© 2024 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of Australian Energy Producers.

Abstract

Due to unforeseen circumstances, the authors of this paper did not present at the Australian Energy Producers Conference & Exhibition.

The Mahu Sag of Junggar Basin, China is rich in alkaline minerals. Generally, the water–rock reactions between hydraulic fluid and alkaline minerals during the hydraulic fracturing process will lead to the precipitation of minerals and block the pore or wellbore, thereby affecting the recovery efficiency. Supercritical carbon dioxide (ScCO2) regarded as a fracturing fluid can significantly improve the recovery of shale oil resources, but there is limited research on the reaction of ScCO2 to water and rock in shale samples rich in alkaline minerals. Therefore, ScCO2 treatment experiments were conducted on shale samples rich in alkaline minerals under 80°C and 10 MPa. Before the experiments, X-ray powder diffraction (XRD) was applied to characterise the mineral properties of the three shale samples. In addition, the duration time of ScCO2 treatment was set at 7 and 20 days to observe the treatment time impacts on the pore structure. Scanning electron microscopy (SEM) analysis and the Mann–Whitney U test were conducted before and after ScCO2 treatment. SEM images show the changes in pore structure. Opening pores are observed due to the interaction between the alkaline mineral and ScCO2. The Mann–Whitney U test shows the changes in fracture toughness. The changes in pore structure also play an important role in fracture toughness. This study investigated the ScCO2 impacts on shale samples rich in alkaline minerals and the analysis of changes in pore structure and fracture toughness can provide theoretical and data evidence to enable on-site optimisation of the ScCO2 fracturing scheme.

Keywords: alkaline mineral, fracture toughness, interaction, Mann–Whitney U test, pore structure, shale, supercritical CO2, treated time.

Biographies

EP23092_B1.gif

Dr Yamin Wang is currently working as a postdoc at the Institute of Energy, Peking University. Her current research is related to the shale oil mobility analysis. Dr Yamin Wang is also interested in microscopic pore structure description, water-mineral reaction and CO2 storage feasibility analysis. She completed her PhD degree from the School of Minerals and Energy Resources Engineering, University of New South Wales (UNSW) in 2021 and her Master’s Degree from UNSW in 2017.

EP23092_B2.gif

Dr Kouqi Liu is the assistant professor at the Institute of Energy, Peking University. His research interests include multi-scale rock mechanics (from nanoscale to macroscale), unconventional resources analysis (petrophysics and reservoir characterisation). He completed his PhD degree from University of North Dakota. Dr Liu was selected as top 2% scientist in the world in 2022.

References

Ao X, Qi Z, Xiang Z, Li Z, Qu H, Wang Z (2020) Swelling of Shales by Supercritical Carbon Dioxide and Its Relationship to Sorption. ACS Omega 5, 19606-19614.
| Crossref | Google Scholar |

Bai B, Ni H-j, Shi X, Guo X, Ding L (2021) The experimental investigation of effect of supercritical CO2 immersion on mechanical properties and pore structure of shale. Energy 228, 120663.
| Crossref | Google Scholar |

Belu Mănescu C, Nuño G (2015) Quantitative effects of the shale oil revolution. Energy Policy 86, 855-866.
| Crossref | Google Scholar |

Dai C, Wang T, Zhao M, Sun X, Gao M, Xu Z, Guan B, Liu P (2018) Impairment mechanism of thickened supercritical carbon dioxide fracturing fluid in tight sandstone gas reservoirs. Fuel 211, 60-66.
| Crossref | Google Scholar |

Dai X, Wang M, Wei C, Zhang J, Wang X, Zou M (2020) Factors affecting shale microscopic pore structure variation during interaction with supercritical CO2. Journal of CO2 Utilization 38, 194-211.
| Crossref | Google Scholar |

Dyer SB, Huang SS, Ali SMF, Jha KNN (1994) Phase Behaviour And Scaled Model Studies of Prototype Saskatchewan Heavy Oils With Carbon Dioxide. Journal of Canadian Petroleum Technology 33(8),.
| Crossref | Google Scholar |

Gaus I (2010) Role and impact of CO2–rock interactions during CO2 storage in sedimentary rocks. International Journal of Greenhouse Gas Control 4(1), 73-89.
| Crossref | Google Scholar |

Hu S, Zhao W, Hou L, Yang Z, Zhu R, Wu S, Bai B, Jin X (2020) Development potential and technical strategy of continental shale oil in China. Petroleum Exploration and Development 47(4), 877-887.
| Crossref | Google Scholar |

Khatib AK, Earlougher RC, Kantar K (1981) CO2 Injection as an Immiscible Application for Enhanced Recovery in Heavy Oil Reservoirs. Paper presented at the SPE California Regional Meeting, Bakersfield, California. https://doi.org/10.2118/9928-MS

Liu K, Jin Z, Zeng L, Ozotta O, Gentzis T, Ostadhassan M (2023) Alteration in the mechanical properties of the Bakken during exposure to supercritical CO2. Energy 262, 125545.
| Crossref | Google Scholar |

Lu Y, Xu Z, Li H, Tang J, Chen X (2021) The influences of super-critical CO2 saturation on tensile characteristics and failure modes of shales. Energy 221, 119824.
| Crossref | Google Scholar |

Lu Y, Liu J, Tang J, Ao X, Li H, Zhou J, Sun X (2022) Pore changes of slickwater-containing shale under supercritical CO2 treatment. Fuel 312, 122775.
| Crossref | Google Scholar |

Middleton RS, Carey JW, Currier RP, Hyman JD, Kang Q, Karra S, Jiménez-Martínez J, Porter ML, Viswanathan HS (2015) Shale gas and non-aqueous fracturing fluids: Opportunities and challenges for supercritical CO2. Applied Energy 147, 500-509.
| Crossref | Google Scholar |

Murray J, King D (2012) Oil’s tipping point has passed. Nature 481(7382), 433-435.
| Crossref | Google Scholar | PubMed |

Ozotta O, Liu K, Gentzis T, Carvajal-Ortiz H, Liu B, Rafieepour S, Ostadhassan M (2021) Pore Structure Alteration of Organic-Rich Shale with Sc-CO2 Exposure: the Bakken Formation. Energy & Fuels 35(6), 5074-5089.
| Crossref | Google Scholar |

Pitzer KS, Schreiber DR (1988) Improving equation-of-state accuracy in the critical region; equations for carbon dioxide and neopentane as examples. Fluid Phase Equilibria 41(1), 1-17.
| Crossref | Google Scholar |

Sayegh SG, Maini BB (1984) Laboratory Evaluation of the CO2 Huff-N-Puff Process for Heavy Oil Reservoirs. Journal of Canadian Petroleum Technology 23(3),.
| Crossref | Google Scholar |

Solarin SA, Gil-Alana LA, Lafuente C (2020) An investigation of long range reliance on shale oil and shale gas production in the U.S. market. Energy 195, 116933.
| Crossref | Google Scholar |

Yin H, Zhou J, Jiang Y, Xian X, Liu Q (2016) Physical and structural changes in shale associated with supercritical CO2 exposure. Fuel 184, 289-303.
| Crossref | Google Scholar |

Zhang X, Lu Y, Tang J, Zhou Z, Liao Y (2017) Experimental study on fracture initiation and propagation in shale using supercritical carbon dioxide fracturing. Fuel 190, 370-378.
| Crossref | Google Scholar |

Zhao Z, Li X, He J, Mao T, Zheng B, Li G (2018) A laboratory investigation of fracture propagation induced by supercritical carbon dioxide fracturing in continental shale with interbeds. Journal of Petroleum Science and Engineering 166, 739-746.
| Crossref | Google Scholar |

Zhijun J, Xunyu C, Jinlian L, Yu Z, Zhe C (2018) The recent exploration progress and resource development strategy of China Petroleum and Chemical Corporation. China Petroleum Exploration 23(1), 14-25.
| Crossref | Google Scholar |

Zou C (2017) ‘Unconventional petroleum geology.’ (Elsevier)