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This paper presents a new fractal seepage model to study the decrease in seepage capacity caused by fluid erosion and pressure changes in porous media. The normalized permeability obtained by our model is in good agreement with the experiments and models in literature and has high accuracy and usability. The results demonstrate that: (1) the larger the instability coefficient, the higher the particle stability, the better the permeability of the porous medium, the later the normalized permeability decreases, and the slower it goes down, and (2) the fractal dimension of the solid skeleton set mainly affects the porosity and permeability of porous media, independent of the stability of solid particles. (3) The fractal dimension of movable particles is one of the main factors affecting the normalized permeability, it does not affect the instability conditions solid-phase particles in the porous media. The proposed model makes full use of the microstructure parameters of porous media, further reveals the mechanism of fluid flow in porous media with particle shedding, and provides a sound theoretical basis for various practical applications in petroleum engineering and other industries. [ABSTRACT FROM AUTHOR]

Transport phenomenon in porous media is essential in various scientific and engineering fields. The permeability and porosity of porous media serve important functions in transport phenomena. In this study, a complex model that considers the characters of pore microstructure and fluid in porous media is developed for the permeability and porosity of porous media. The flow rate expressions of this model are compared with those of previous models. As the proposed models relate the properties of fluids to the structural parameters of porous media, the various expressions of the developed model can reveal the phenomena of all types of fluid flow in a variety of porous media. The predicted permeabilities and porosities show good agreement with the available experimental data and illustrate that the proposed model can be used to characterize flow in porous media. [ABSTRACT FROM AUTHOR]

Abstract: Observational procedures are used to develop liquid loading models associated with gas production. The performance of various critical liquid-removal flow rate models are compared and critiqued by examining model outputs. Critical liquid-removal flow rates calculated by different models are found to vary considerably. Using the balance relationship between total surface free energy of liquid droplets and turbulent kinetic energy of gas flow, we developed a new model that considers the influence of droplet diameter on critical liquid-removal flow rate of gas wells. Model reliability is verified by comparing model results with gas well production data from four gas reservoirs in China. [Copyright &y& Elsevier]

Abstract On the basis of the seismic data volume of a certain well group unit of the Tahe fracture–vuggy reservoirs, the similarity theory is adopted, and a numerical model with geometric, kinematic, dynamic, and fracture–cavity characteristic parameter similarities is designed. Moreover, a large–scale three–dimensional physical karst cave model is built with the carving technology. The model is used in the experimental study of two–phase flow of oil/water during waterflood development and in the analysis of relevant influencing factors. Results show that the displacement efficiency of low–high mode is obviously superior to the case of high–low mode. A high crude oil viscosity is found to equate to a low ultimate recovery. High–velocity water flooding improves ultimate recovery but results earlier water breakthrough. Well shutdown improves recovery factor and well shutdown during middle water cut stage achieves optimum effects. Bottom water energy benefits oil reservoir exploitation to some degree. Highlights • A large–scale three–dimensional physical karst cave model is built to study the two–phase flow of oil/water. • Displacement efficiency of low–high mode is obviously superior to the case of high–low mode. • A high crude oil viscosity is found to equate to a low ultimate recovery. • High–velocity water flooding improves ultimate recovery but results earlier water breakthrough. • Well shutdown during middle water cut stage achieves optimum effects. [ABSTRACT FROM AUTHOR]