Gelled particles can be transferred deeply inside oil reservoirs to block water channels due to their physicochemical characteristics, including swelling, deformation, and synergetic effect （reacting with polymers）,...Gelled particles can be transferred deeply inside oil reservoirs to block water channels due to their physicochemical characteristics, including swelling, deformation, and synergetic effect （reacting with polymers）, and then the injection profiles are significantly modified. At present, research on gelled particles is mainly focused on laboratory studies of drive mechanisms, and rarely on mathematical models describing the blocking process of gelled particles. In this paper, the blocking process of gelled particles is divided into two sub-processes： deposition and desorption due to particle deformation. A mathematical model based on filtration theory is proposed considering the effect of characteristics of gelled particles on the blocking process. Blocking laws were simulated and researched using the mathematical model. Results of the simulation of the blocking of gelled particles are quite consistent with the experimental results, which confirms the reliability of the mathematical model developed.展开更多
The swelling particle grouting material has demonstrated remarkable plugging effectiveness in high-pressure and large-flow burst water within karst pipelines.Currently,current research on the rheolog-ical model,flow c...The swelling particle grouting material has demonstrated remarkable plugging effectiveness in high-pressure and large-flow burst water within karst pipelines.Currently,current research on the rheolog-ical model,flow computation theory,and plugging mechanism of this material is lacking.The conven-tional grouting slurry diffusion process,using the liquid-liquid two-phase flow method,fails to accurately simulate high solubility slurry and particle swelling.To address these limitations,this study established a precise constitutive model to describe the swelling particle slurry diffusion process in dynamic water.Additionally,a coupling calculation method was proposed to analyze the spatiotemporal heterogeneity of viscosity during slurry diffusion by considering the migration of slurry and the changes in viscosity.To investigate the interaction between particle swelling and flow field changes,a Compu-tational Fluid Dynamics-Discrete Element Method(CFD-DEM)coupling model was developed for the diffusion of swelling particle slurry.It is demonstrated that slurry viscosity increases exponentially within the diffusion front as the particle swelling rate rises,and the drag force exhibits an intriguing behavior of initially increasing and then decreasing as the slurry flows through the pipeline.Further-more,the CFD-DEM coupling model proved to be more accurate in describing viscosity distribution and diffusion distance compared to the finite element solution.The primary objective of this paper is to reveal the plugging mechanism and provide theoretical support for the engineering application of the swelling particle grouting material.展开更多
Many geotechnical structures,such as the subgrade of high-speed railway,are extremely sensitive to micro deformations.As one of the most commonly used indexes in China to evaluate the potential swelling level of expan...Many geotechnical structures,such as the subgrade of high-speed railway,are extremely sensitive to micro deformations.As one of the most commonly used indexes in China to evaluate the potential swelling level of expansive soils,the effectiveness and accuracy of free swelling ratio should be highly required.However,due to the deficiency of geotechnical test regulations for the free swelling ratio test,non-negligible variation difference is often observed among the test results of the same type of soil samples.Thus,a series of laboratory tests are conducted to figure out the influences of soil particle size,initial soil temperature,and wet-dry circulation on the free swelling ratio of expansive soils.The results show that the initial soil temperature exerts an obvious influence on free swelling ratio and a relative weak influence on soil mass of expansive soil with the micro soil particle size(d<0.075 mm),and the correlation becomes unclear when soil particle size is within the range of 0.075 mm≤d<0.500 mm.A larger particle size of expansive soils induces a larger free swelling ratio and soil mass in the soil measuring cup regardless of initial soil temperature.However,the enlarging amplitude decreases as the particle size of expansive soils increases.There is a progressive enlargement of free swelling ratio at the first two wet-dry cycles and then it attenuates gradually when the number of wetdry cycles further increases.展开更多
Controlled-release urea was fabricated by coating urea particles with a polymer latex in a fluidized bed. The latex film coated on the urea particle surface was hydrophilic and swelled in water. The film swelling in w...Controlled-release urea was fabricated by coating urea particles with a polymer latex in a fluidized bed. The latex film coated on the urea particle surface was hydrophilic and swelled in water. The film swelling in water and urea solution and properties of the swollen film were studied. The film swelling in urea solution followed the Lagergren＇s pseudo-first order kinetics with the swelling coefficient depending on the film material and experimental conditions. The effects of swelling on film structure and permeability were studied. The film permeability coefficient decreased with increasing swelling ratio with an approx- imately linear relationship. Based on the film formation process and structure of the swollen film. a film structure model consisting of dense and swollen phases was proposed. The permeability coefficient of the spherical film and cumulative release of urea from the coated particles were calculated from the swelling ratio of the spherical film. which was determined from the expansion curve of the coated particle during the release process, The calculated and measured release curves agreed well, This research indicates that the swelling of the hydrophilic film and the controlled-release mechanism are important factors in the development of controlled-release urea.展开更多
基金supported by the National HighTechnology Research and Development Program of China(863 Program)(2007AA06Z214)"Taishan Scholars"Construction Project(No.ts20070704).
文摘Gelled particles can be transferred deeply inside oil reservoirs to block water channels due to their physicochemical characteristics, including swelling, deformation, and synergetic effect （reacting with polymers）, and then the injection profiles are significantly modified. At present, research on gelled particles is mainly focused on laboratory studies of drive mechanisms, and rarely on mathematical models describing the blocking process of gelled particles. In this paper, the blocking process of gelled particles is divided into two sub-processes： deposition and desorption due to particle deformation. A mathematical model based on filtration theory is proposed considering the effect of characteristics of gelled particles on the blocking process. Blocking laws were simulated and researched using the mathematical model. Results of the simulation of the blocking of gelled particles are quite consistent with the experimental results, which confirms the reliability of the mathematical model developed.
基金supported by the National Natural Science Foundation of China for the Young Scientists Fund,China (grant No.52109126)the National Key Research and Development Program of China,China (grant No.202103AA080016).
文摘The swelling particle grouting material has demonstrated remarkable plugging effectiveness in high-pressure and large-flow burst water within karst pipelines.Currently,current research on the rheolog-ical model,flow computation theory,and plugging mechanism of this material is lacking.The conven-tional grouting slurry diffusion process,using the liquid-liquid two-phase flow method,fails to accurately simulate high solubility slurry and particle swelling.To address these limitations,this study established a precise constitutive model to describe the swelling particle slurry diffusion process in dynamic water.Additionally,a coupling calculation method was proposed to analyze the spatiotemporal heterogeneity of viscosity during slurry diffusion by considering the migration of slurry and the changes in viscosity.To investigate the interaction between particle swelling and flow field changes,a Compu-tational Fluid Dynamics-Discrete Element Method(CFD-DEM)coupling model was developed for the diffusion of swelling particle slurry.It is demonstrated that slurry viscosity increases exponentially within the diffusion front as the particle swelling rate rises,and the drag force exhibits an intriguing behavior of initially increasing and then decreasing as the slurry flows through the pipeline.Further-more,the CFD-DEM coupling model proved to be more accurate in describing viscosity distribution and diffusion distance compared to the finite element solution.The primary objective of this paper is to reveal the plugging mechanism and provide theoretical support for the engineering application of the swelling particle grouting material.
基金Project(2016M591957) supported by the China Postdoctoral Science FoundationProjects(51878667,51678571)supported by the National Natural Science Foundation of ChinaProject(2017XKQY050) supported by the Fundamental Research Funds for the Central Universities,China。
文摘Many geotechnical structures,such as the subgrade of high-speed railway,are extremely sensitive to micro deformations.As one of the most commonly used indexes in China to evaluate the potential swelling level of expansive soils,the effectiveness and accuracy of free swelling ratio should be highly required.However,due to the deficiency of geotechnical test regulations for the free swelling ratio test,non-negligible variation difference is often observed among the test results of the same type of soil samples.Thus,a series of laboratory tests are conducted to figure out the influences of soil particle size,initial soil temperature,and wet-dry circulation on the free swelling ratio of expansive soils.The results show that the initial soil temperature exerts an obvious influence on free swelling ratio and a relative weak influence on soil mass of expansive soil with the micro soil particle size(d<0.075 mm),and the correlation becomes unclear when soil particle size is within the range of 0.075 mm≤d<0.500 mm.A larger particle size of expansive soils induces a larger free swelling ratio and soil mass in the soil measuring cup regardless of initial soil temperature.However,the enlarging amplitude decreases as the particle size of expansive soils increases.There is a progressive enlargement of free swelling ratio at the first two wet-dry cycles and then it attenuates gradually when the number of wetdry cycles further increases.
基金The authors express their gratitude for the financial support of this study by the National Natural Science Foundation of China （NSFC No. 20876085）.
文摘Controlled-release urea was fabricated by coating urea particles with a polymer latex in a fluidized bed. The latex film coated on the urea particle surface was hydrophilic and swelled in water. The film swelling in water and urea solution and properties of the swollen film were studied. The film swelling in urea solution followed the Lagergren＇s pseudo-first order kinetics with the swelling coefficient depending on the film material and experimental conditions. The effects of swelling on film structure and permeability were studied. The film permeability coefficient decreased with increasing swelling ratio with an approx- imately linear relationship. Based on the film formation process and structure of the swollen film. a film structure model consisting of dense and swollen phases was proposed. The permeability coefficient of the spherical film and cumulative release of urea from the coated particles were calculated from the swelling ratio of the spherical film. which was determined from the expansion curve of the coated particle during the release process, The calculated and measured release curves agreed well, This research indicates that the swelling of the hydrophilic film and the controlled-release mechanism are important factors in the development of controlled-release urea.
