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Keyvani F, Safaei A, Kazemzadeh Y, Riazi M, Qajar J. Impact of nanopore confinement on phase behavior and enriched gas minimum miscibility pressure in asphaltenic tight oil reservoirs. Sci Rep 2024; 14:13405. [PMID: 38862707 PMCID: PMC11167058 DOI: 10.1038/s41598-024-64194-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 06/06/2024] [Indexed: 06/13/2024] Open
Abstract
Miscible gas injection in tight/shale oil reservoirs presents a complex problem due to various factors, including the presence of a large number of nanopores in the rock structure and asphaltene and heavy components in crude oil. This method performs best when the gas injection pressure exceeds the minimum miscibility pressure (MMP). Accordingly, accurate calculation of the MMP is of special importance. A critical issue that needs to be considered is that the phase behavior of the fluid in confined nanopores is substantially different from that of conventional reservoirs. The confinement effect may significantly affect fluid properties, flow, and transport phenomena characteristics in pore space, e.g., considerably changing the critical properties and enhancing fluid adsorption on the pore wall. In this study, we have investigated the MMP between an asphaltenic crude oil and enriched natural gas using Peng-Robinson (PR) and cubic-plus-association (CPA) equations of state (EoSs) by considering the effect of confinement, adsorption, the shift of critical properties, and the presence of asphaltene. According to the best of our knowledge, this is the first time a model has been developed considering all these factors for use in porous media. We used the vanishing interfacial tension (VIT) method and slim tube test data to calculate the MMP and examined the effects of pore radius, type/composition of injected gas, and asphaltene type on the computed MMP. The results showed that the MMP increased with an increasing radius of up to 100 nm and then remained almost constant. This is while the gas enrichment reduced the MMP. Asphaltene presence changed the trend of IFT reduction and delayed the miscibility achievement so that it was about 61% different from the model without the asphaltene precipitation effect. However, the type of asphaltene had little impact on the MMP, and the controlling factor was the amount of asphaltene in the oil. Moreover, although cubic EoSs are particularly popular for their simplicity and accuracy in predicting the behavior of hydrocarbon fluids, the CPA EoS is more accurate for asphaltenic oils, especially when the operating pressure is within the asphaltene precipitation range.
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Affiliation(s)
- Fatemeh Keyvani
- Department of Petroleum Engineering, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz, 7193616511, Iran
| | - Ali Safaei
- Fouman Faculty of Engineering, College of Engineering, University of Tehran, Tehran, 4358139115, Iran
- Enhanced Oil Recovery (EOR) Research Centre, IOR/EOR Research Institute, Shiraz University, Shiraz, 7193616511, Iran
| | - Yousef Kazemzadeh
- Department of Petroleum Engineering, Faculty of Petroleum, Gas, and Petrochemical Engineering, Persian Gulf University, Bushehr, 7516913817, Iran
| | - Masoud Riazi
- Enhanced Oil Recovery (EOR) Research Centre, IOR/EOR Research Institute, Shiraz University, Shiraz, 7193616511, Iran.
- School of Mining and Geoscience, Nazarbayev University, Kabanbay Batyr 53, 010000, Astana, Kazakhstan.
| | - Jafar Qajar
- Department of Petroleum Engineering, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz, 7193616511, Iran.
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, 3584 CS, Utrecht, The Netherlands.
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Hu S, Wang X, Wang E. Experimental study of true triaxial high pressure subcritical water impact fracturing. Sci Rep 2024; 14:1150. [PMID: 38212461 PMCID: PMC10784540 DOI: 10.1038/s41598-024-51189-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 01/01/2024] [Indexed: 01/13/2024] Open
Abstract
A new fluid alternative to slick water for fracturing shale gas can reduce the waste of water resources and improve the extraction efficiency, enabling volumetric fracturing. For the new fracturing technique, the experiments of different release pressures under pre-injection and for pre-injection were conducted using a self-designed true triaxial experimental system, and the pressure pulse curves were plotted to analyze the fracturing principle. The experimental results showed that: (1) the pressure rise curve in the reactor can be divided into five stages: initial reaction, linear pressure rise, rate slowdown, instantaneous pressure release, and residual pressure stages; (2) Pre-filling fracturing requires a smaller expansion ratio, weaker pressure degradation, resulting in better fracturing effect; (3) The increase in the initial fracture length leads to an increase in the pressure required to extend the fracture, and high-pressure subcritical water impact fracturing achieved fracture extension at a lower fluid pressure; (4) The fractal dimension has a strong linear relationship with fracture complexity, which is a new option when evaluating the fracturing effect. Volumetric fracturing allows for the creation of more tiny trenches that increase reservoir permeability, leading to better recovery of the reservoir's energy resources.
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Affiliation(s)
- Shaobin Hu
- Tunnel and Underground Engineering Institute, College of Civil and Transportation Engineering, HoHai University, Nanjing, 210098, Jiangsu, China.
| | - Xiaofei Wang
- School of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116, Jiangsu, China
| | - Enyuan Wang
- School of Safety Engineering, China University of Mining and Technology, Xuzhou, 221116, Jiangsu, China.
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Wu S, Wang H, Yuan G, Hu B, Sun Z, Yan S, Li Y. Carbon Dioxide Flow Behavior through Nanopores: Implication for CO 2 Sequestration in Unconventional Gas Reservoirs. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c03123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Shan Wu
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou221116, China
| | - Hongya Wang
- National Engineering Research Center of Coalbed Methane Development & Utilization, Beijing100095, China
- PetroChina Coalbed Methane Company Limited, Beijing100028, China
| | - Gang Yuan
- Northwestern Sichuan Gas District, PetroChina Southwest Oil & Gas Field Company, Jiangyou621741, Sichuan, China
| | - Bingying Hu
- Weinan Transportation Service Center, Traffic Complex Building, West Section of Dongfeng, Weinan714026, Shanxi, China
| | - Zheng Sun
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou221116, China
- Department of Petroleum Engineering, Texas A&M University, College Station, Texas77843, United States
| | - Shuhui Yan
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou221116, China
| | - Yaohui Li
- State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou221116, China
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Song Y, Song Z, Zhang Z, Chang X, Wang D, Hui G. Phase Behavior of CO 2-CH 4-Water Mixtures in Shale Nanopores Considering Fluid Adsorption and Capillary Pressure. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c00431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yilei Song
- State Key Laboratory of Petroleum Resources and Prospecting and Unconventional Petroleum Research Institute, China University of Petroleum-Beijing, Beijing 102249, China
| | - Zhaojie Song
- State Key Laboratory of Petroleum Resources and Prospecting and Unconventional Petroleum Research Institute, China University of Petroleum-Beijing, Beijing 102249, China
| | - Zhuoya Zhang
- State Key Laboratory of Petroleum Resources and Prospecting and Unconventional Petroleum Research Institute, China University of Petroleum-Beijing, Beijing 102249, China
| | - Xuya Chang
- State Key Laboratory of Petroleum Resources and Prospecting and Unconventional Petroleum Research Institute, China University of Petroleum-Beijing, Beijing 102249, China
| | - Daigang Wang
- State Key Laboratory of Petroleum Resources and Prospecting and Unconventional Petroleum Research Institute, China University of Petroleum-Beijing, Beijing 102249, China
| | - Gang Hui
- State Key Laboratory of Petroleum Resources and Prospecting and Unconventional Petroleum Research Institute, China University of Petroleum-Beijing, Beijing 102249, China
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