Influence of micro-heterogeneity of fractured-porous reservoirs on the water flooding mobilization law

Zhao, Wenqi; Zhao, Lun; Jia, Pin; Wang, Peng; Hou, Jue

doi:10.1016/j.seta.2022.102694

Cited by 6 publications

(7 citation statements)

References 19 publications

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“…Dissolved pores include intergranular dissolved pores and dissolved pores within minerals, which are mainly formed by the dissolution of unstable components in feldspar (Figure 3e). Microfractures are formed by the fracture of minerals under tectonic stress and their diameters are usually smaller than 1 mm, which could increase the permeability of the reservoir to improve the quality of the reservoir (L. B. Zhao et al, 2017; W. Q. Zhao et al, 2022). The main types of throat are flake throat, curved flake throat and a small amount of necking throat (Figure 3d).…”

Section: Resultsmentioning

confidence: 99%

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Pore‐throat structure characteristics and fluid mobility analysis of tight sandstone reservoirs in Shaximiao Formation, Central Sichuan

et al. 2023

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The pore‐throat structure and fluid mobility are the key factors of tight sandstone reservoir classification and evaluation. Taking the Jurassic Shaximiao Formation tight sandstone reservoir in Central Sichuan Basin as an example, 19 samples were analysed by casting thin sections, scanning electron microscopy, high‐pressure mercury injection and nuclear magnetic resonance to clarify the pore‐throat structure, the fluid motility and its controlling factors. The results show that the pore type of Shaximiao Formation tight sandstone reservoir consist of intergranular pores, dissolved pores and a few microfractures. Based on the feature of capillary pressure curve, the pore‐throat structure was classified into three types, corresponding to different movable fluid characteristics. The Type I has large pore and throat radius, good pore‐throat connectivity, small fractal dimension, weak reservoir heterogeneity and strong fluid motility. The distribution range of pore‐throat radius is mainly from 0.3 to 1.1 μm and the average movable fluid porosity (MFP) and movable fluid saturation (MFS) are 6.04% and 49.93%. The Type II has poor pore‐throat sorting, weak fluid motility and the distribution range of pore‐throat radius is 0.01–0.03 μm and 0.2–0.8 μm. The average MFP and MFS of Type II are 1.13% and 14.3%. The Type III has the smallest pore‐throat radius and the largest fractal dimension, corresponding to the most complex pore‐throat structure, which lead to the worst fluid mobility. The average MFP and MFS are 0.49% and 12.76%. The fluid mobility of the tight sandstone reservoir is affected by physical properties and pore‐throat structure. The reservoirs with large pore‐throat size, good connectivity between pore and throat, and low heterogeneity have higher MFP and saturation. Moreover, the mineral compositions have different effects on fluid mobility of the tight sandstone. The feldspar positively affects fluid mobility, while the clay minerals negatively affect fluid mobility.

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Section: Resultsmentioning

confidence: 99%

“…Zhao et al, 2017; W. Q. Zhao et al, 2022). The main types of throat are flake throat, curved flake throat and a small amount of necking throat (Figure 3d).…”

Section: Reservoir Petrological Characteristics Physical Properties A...mentioning

confidence: 98%

Pore‐throat structure characteristics and fluid mobility analysis of tight sandstone reservoirs in Shaximiao Formation, Central Sichuan

et al. 2023

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“…In the process of water flooding, it is more and more difficult to improve oil recovery, and the water cut of oil wells is also increasing. In the late stage of oilfield development, longterm water injection will affect the pore medium in the reservoir, resulting in reservoir heterogeneity [4][5][6], thus greatly reducing water-injection efficiency and oil recovery [7,8]. In order to change the current situation of high water cut in oil wells and improve oil recovery, reasonable measures must be taken to control the high permeability channels between oil and water wells [9,10].…”

Section: Introductionmentioning

confidence: 99%

Study on the Adaptability Evaluation of Micro-Dispersed-Gel-Strengthened-Alkali-Compound System and the Production Mechanism of Crude Oil

Wang,

Wu,

Liu

et al. 2024

Processes

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A novel micro-dispersed-gel (MDG)-strengthened-alkali-compound flooding system was proposed for enhanced oil recovery in high-water-cut mature oilfields. Micro-dispersed gel has different adaptability and application schemes with sodium carbonate and sodium hydroxide. The MDG-strengthened-alkali flooding system can reduce the interfacial tension to an ultra-low interfacial-tension level of 10−2 mN/m, which can reverse the wettability of rock surface. After 30 days aging, the MDG-strengthened-Na2CO3 flooding system has good viscosity retention of 74.5%, with an emulsion stability of 79.13%. The enhanced-oil-recovery ability of the MDG-strengthened-Na2CO3 (MDGSC) flooding system is 43.91%, which is slightly weaker than the 47.78% of the MDG-strengthened-NaOH (MDGSH) flooding system. The crude-oil-production mechanism of the two systems is different, but they all show excellent performance in enhanced oil recovery. The MDGSC flooding system mainly regulates and seals micro-fractures, forcing subsequent injected water to enter the low-permeability area, and it has the ability to wash the remaining oil in micro-fractures. The MDGSH flooding system mainly removes the remaining oil on the rock wall surface in the micro-fractures by efficient washing, and the MDG particles can also form weak plugging of the micro-fractures. The MDG-strengthened-alkali flooding system can be used as an alternative to enhance oil recovery in high-water-cut and highly heterogeneous mature oilfields.

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“…However, real oilfield reservoirs are high-temperature and high-pressure porous media with high non-homogeneity [15,16]. The transport of fluids and mechanisms is very complex.…”

Section: Introductionmentioning

confidence: 99%

“…The microscopic glass etching model is a pore-scale model etched on a glass plate based on the pore throat structure of the natural core. It has the advantage of visualization, which can visually explore the distribution state of the remaining oil and its transport [15,18,19]. The simulated water flooding experiments are at the core scale, which can approach the real stratigraphic conditions to the maximum extent [20].…”

Section: Introductionmentioning

confidence: 99%

Pore- and Core-Scale Recovery Performance of Consortium Bacteria from Low-Permeability Reservoir

Bian,

Song,

Zhi

et al. 2023

Microorganisms

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Performance evaluation of microorganisms that have emulsifying and degrading effects on crude oil has been extensively conducted in the laboratory. However, the ultimate goal of microbial enhanced oil recovery is field application, so the pilot simulation experiments are crucial. In this study, a micro-visualization model and the real cores were chosen to investigate the actual recovery efficiency and the mechanism of the consortium bacteria B-ALL, which has been proven to have good emulsification and degradation effects in lab studies in porous media. At the same time, the cast thin sections and rate-controlled porosimetry were combined to analyze the pore throat structure of the displacement core. It was found that the recovery efficiency was positively correlated with the microbial injection volume as well as the incubation time. For the microscopic model with high pores and high permeability, the efficiency of secondary water flooding can be increased by 44.77% after six days of incubation with two pore volume microbes. For the real tight cores, the maximum secondary water flooding efficiency under the same condition was 6.98%. Through visual modeling, microorganisms increase the oil washing efficiency mainly by emulsification and changing the wettability. The generated oil droplets will play a role in plugging and improving the wave efficiency. However, tight reservoirs have the characteristics of large pores and small throats, and curved and necking throats are developed, greatly reducing permeability. The microbial recovery efficiency was lower under shorter cultivation times. This study provides a practical basis for the application of consortium bacteria in tight oil fields to enhance recovery.

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Influence of micro-heterogeneity of fractured-porous reservoirs on the water flooding mobilization law

Cited by 6 publications

References 19 publications

Pore‐throat structure characteristics and fluid mobility analysis of tight sandstone reservoirs in Shaximiao Formation, Central Sichuan

Pore‐throat structure characteristics and fluid mobility analysis of tight sandstone reservoirs in Shaximiao Formation, Central Sichuan

Study on the Adaptability Evaluation of Micro-Dispersed-Gel-Strengthened-Alkali-Compound System and the Production Mechanism of Crude Oil

Pore- and Core-Scale Recovery Performance of Consortium Bacteria from Low-Permeability Reservoir

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