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He H, Tian Y, Zhang L, Li H, Guo Y, Liu Y, Liu Y. Insights into the Injectivity and Propagation Behavior of Preformed Particle Gel (PPG) in a Low-Medium-Permeability Reservoir. Gels 2024; 10:475. [PMID: 39057498 PMCID: PMC11276603 DOI: 10.3390/gels10070475] [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: 06/20/2024] [Revised: 07/14/2024] [Accepted: 07/16/2024] [Indexed: 07/28/2024] Open
Abstract
Heterogeneous phase combined flooding (HPCF) has been a promising technology used for enhancing oil recovery in heterogeneous mature reservoirs. However, the injectivity and propagation behavior of preformed particle gel (PPG) in low-medium-permeability reservoir porous media is crucial for HPCF treatment in a low-medium-permeability reservoir. Thus, the injectivity and propagation behavior of preformed particle gel in a low-medium-permeability reservoir were systematically studied by conducting a series of sand pack flooding experiments. The matching factor (δ) was defined as the ratio of the average size of PPG particles to the mean size of pore throats and the pressure difference ratio (β) was proposed to characterize the injectivity and propagation ability of PPG. The results show that with the increase in particle size and the decrease in permeability, the resistance factor and residual resistance factor increase. With the increase in the matching factor, the resistance factor and residual resistance factor increase. The higher the resistance factor and residual resistance factor are, the worse the injectivity of particles is. By fitting the relationship curve, PPG injection and propagation standards were established: when the matching coefficient is less than 55 and β is less than 3.4, PPG can be injected; when the matching coefficient is 55-72 and β is 3.4-6.5, PPG injection is difficult; when the matching coefficient is greater than 72 and β is greater than 6.5, PPG cannot be injected Thus, the matching relationship between PPG particle size and reservoir permeability was obtained. This research will provide theoretical support for further EOR research and field application of heterogeneous phase combined flooding.
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Affiliation(s)
- Hong He
- College of Petroleum Engineering, Yangtze University, Wuhan 430100, China;
- Key Laboratory of Drilling and Production Engineering for Oil and Gas, Wuhan 430100, China
| | - Yuhang Tian
- College of Petroleum Engineering, Yangtze University, Wuhan 430100, China;
- Key Laboratory of Drilling and Production Engineering for Oil and Gas, Wuhan 430100, China
| | - Lianfeng Zhang
- Research Institute of Exploration and Development, Sinopec Henan Oilfield Company, Nanyang 473132, China
- Henan Provincial Key Laboratory of Enhanced Oil Recovery, Nanyang 473132, China
| | - Hongsheng Li
- Research Institute of Exploration and Development, Sinopec Henan Oilfield Company, Nanyang 473132, China
- Henan Provincial Key Laboratory of Enhanced Oil Recovery, Nanyang 473132, China
| | - Yan Guo
- Research Institute of Exploration and Development, Sinopec Henan Oilfield Company, Nanyang 473132, China
- Henan Provincial Key Laboratory of Enhanced Oil Recovery, Nanyang 473132, China
| | - Yu Liu
- Research Institute of Exploration and Development, Sinopec Henan Oilfield Company, Nanyang 473132, China
- Henan Provincial Key Laboratory of Enhanced Oil Recovery, Nanyang 473132, China
| | - Yifei Liu
- College of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266555, China;
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Sun X, Suo L, Huang Y, Wang H, Yu H, Xu C, Xu J, Qin X, Sun W, Cao Y, Liu T. Study on the Occurrence Characteristics of the Remaining Oil in Sandstone Reservoirs with Different Permeability after Polymer Flooding. Polymers (Basel) 2024; 16:1902. [PMID: 39000757 PMCID: PMC11244145 DOI: 10.3390/polym16131902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 06/23/2024] [Accepted: 06/24/2024] [Indexed: 07/17/2024] Open
Abstract
After polymer flooding, the heterogeneity between different layers intensifies, forming intricate seepage channels and fluid diversions, which results in decreased circulation efficiency and lower recovery rates, leaving a significant amount of residual oil trapped within the reservoir. Understanding the characteristics of residual oil occurrence is crucial for enhancing oil recovery post-polymer flooding. This study focused on sandstone reservoirs with varying permeability in the Saertu block of the Daqing oilfield. Using cryosectioning and laser scanning confocal microscopy, the occurrence characteristics of the residual oil in these sandstone reservoirs post-polymer flooding were investigated. Additionally, micro-CT and scanning electron microscopy were employed to analyze the impact of the pore structure on the distribution characteristics of the residual oil. The results indicate that laser scanning confocal images reveal that post-polymer flooding, the residual oil in high- and low-permeability sandstone reservoirs predominantly exists in a bound state (average > 47%), mostly as particle-adsorbed oil. In contrast, the residual oil in medium-permeability reservoirs is primarily in a free state (average > 49%), mostly as intergranular-adsorbed oil. In high-permeability sandstone reservoirs, heavy oil components are mainly in a particle-adsorbed form; in medium-permeability sandstone reservoirs, residual oil predominantly consists of heavy components, with most light components occurring in a clustered form; in low-permeability sandstone reservoirs, clustered residual oil exists in a balanced coexistence of light and heavy components, while the heavy components primarily exist in a particle-adsorbed form. Post-polymer flooding, the large pore-throat structure in high-permeability sandstone reservoirs results in effective displacement and less free residual oil; medium-permeability sandstone reservoirs, with medium-large pores and throats, have preferential channels and fine particles blocking the throats, leading to some unswept pores and more free residual oil; low-permeability sandstone reservoirs, with small pores and throats, exhibit weak displacement forces and poor mobility, resulting in more bound residual oil. The distribution and content of clay particles and clay minerals, along with the complex microscopic pore structure, are the main factors causing the differences in the residual oil occurrence states in sandstones with varying permeability.
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Affiliation(s)
- Xianda Sun
- National Key Laboratory of Continental Shale Oil, Northeast Petroleum University, Daqing 163318, China
| | - Limin Suo
- College of Information and Electrical Engineering, Heilongjiang Bayi Agricultural University, Daqing 163319, China
| | - Yuanjing Huang
- National Key Laboratory of Continental Shale Oil, Northeast Petroleum University, Daqing 163318, China
| | - Hongyu Wang
- National Key Laboratory of Continental Shale Oil, Northeast Petroleum University, Daqing 163318, China
| | - Han Yu
- National Key Laboratory of Continental Shale Oil, Northeast Petroleum University, Daqing 163318, China
| | - Chengwu Xu
- National Key Laboratory of Continental Shale Oil, Northeast Petroleum University, Daqing 163318, China
| | - Jian Xu
- National Key Laboratory of Continental Shale Oil, Northeast Petroleum University, Daqing 163318, China
| | - Xudong Qin
- National Key Laboratory of Continental Shale Oil, Northeast Petroleum University, Daqing 163318, China
| | - Wenying Sun
- National Key Laboratory of Continental Shale Oil, Northeast Petroleum University, Daqing 163318, China
| | - Yangdong Cao
- National Key Laboratory of Continental Shale Oil, Northeast Petroleum University, Daqing 163318, China
| | - Tao Liu
- National Key Laboratory of Continental Shale Oil, Northeast Petroleum University, Daqing 163318, China
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Yang Y, Cao X, Ji Y, Zou R. Mechanistic Insights into a Novel Controllable Phase-Transition Polymer for Enhanced Oil Recovery in Mature Waterflooding Reservoirs. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:3101. [PMID: 38132998 PMCID: PMC10745705 DOI: 10.3390/nano13243101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 11/26/2023] [Accepted: 11/26/2023] [Indexed: 12/23/2023]
Abstract
Expanding swept volume technology via continuous-phase polymer solution and dispersed-phase particle gel is an important technique to increase oil production and control water production in mature waterflooding reservoirs. However, problems such as the low viscosity retention rate, deep migration, and weak mobility control of conventional polymers, and the contradiction between migration distance of particle gel and plugging strength, restrict the long-term effectiveness of oil displacement agents and the in-depth sweep efficiency expanding capability in reservoirs. Combined with the technical advantages of polymer and particle gel, a novel controllable phase-transition polymer was developed and systematically studied to gain mechanistic insights into enhanced oil recovery for mature waterflooding reservoirs. To reveal the phase-transition mechanism, the molecular structure, morphology, and rheological properties of the controllable phase-transition polymer were characterized before and after phase transition. The propagation behavior of the controllable phase-transition polymer in porous media was studied by conducting long core flow experiments. Two-dimensional micro visualization and parallel core flooding experiments were performed to investigate the EOR mechanism from porous media to pore level. Results show that the controllable phase-transition polymer could change phase from dispersed-phase particle gel to continuous-phase solution with the prolongation of ageing time. The controllable phase-transition polymer exhibited phase-transition behavior and good propagation capability in porous media. The results of micro visualization flooding experiments showed that the incremental oil recovery of the controllable phase-transition polymer was highest when a particle gel and polymer solution coexisted, followed by a pure continuous-phase polymer solution and pure dispersed-phase particle gel suspension. The recovery rate of the novel controllable phase-transition polymer was 27.2% after waterflooding, which was 8.9% higher than that of conventional polymer, providing a promising candidate for oilfield application.
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Affiliation(s)
- Yong Yang
- Shengli Oilfield, SINOPEC, Dongying 257001, China; (Y.Y.); (X.C.); (Y.J.)
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Xiaopeng Cao
- Shengli Oilfield, SINOPEC, Dongying 257001, China; (Y.Y.); (X.C.); (Y.J.)
| | - Yanfeng Ji
- Shengli Oilfield, SINOPEC, Dongying 257001, China; (Y.Y.); (X.C.); (Y.J.)
| | - Ruqiang Zou
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
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