Experimental Research on Multiphase Liquid Mobilization and Motion in Capillary and Micro Models Subjected to External Low Frequency Vibratory Excitations PDF Download

Author: Yihe Zhang
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Languages : en
Pages : 0

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Book Description
The research of this dissertation experimentally investigates the impacts of external vibratory excitation on the mobilization and motion of multiphase liquid in capillary and microcell models, aiming for understanding the mechanism of oil-water mobilization and flow in pore structures subjected to external excitations. Experiments with capillary models are first conducted; in which both straight capillary and curved capillary models are employed as an analogue of the pore structures. The mobilization and motion of an oil slug trapped in the capillary models with capillary forces are studied in the research. The models considered are subjected to both external pressures created by water injection and vibratory excitations. The focuses of the experimental investigations are on the variation of the pressure drop across the capillary model, the oil slug travel distance in the model in a fixed time duration, and the flow phenomena during the period of mobilization and flow of the oil slug. It is found in the investigations, in comparing the situations of with and without external excitations, proper vibratory excitations may positively affect the mobilization and flow of the oil slug in the capillary models, in terms of reducing the external pressure needed for mobilizing the oil slug, stabilizing the flow of the oil slug and increasing the oil slug travel distance in a fixed duration. The joint effects of the external pressure and vibratory excitation on the mobilization and flow of the oil slug are measured and quantified in the research. The optimal conditions in terms of external pressure and vibration frequency and amplitude for promoting the oil slug mobilization and stable flow are also searched and determined via the experiments of the research. Two-dimensional micro model are more close to the pore structures of the reservoir in oil field. To study the motion of oil-water liquid in a two-dimensional manner, an etched glass micro model is designed and employed in the research to study the liquid mobilization and flow in a network pore structure. The intention of this study is to understand the mechanism of the external water pressure and vibratory excitation on oil recovery from liquid saturated porous media of a reservoir. Experiments without vibratory excitation are first conducted on the model and various phenomena are observed in the experiments, including the development of water film and water patches surrounding the oil droplets and oil patches, and the variations of the contact angles of the oil droplets. The experimental investigations with application of vibration excitation fall in two categories: oil displacement by applying vibration excitation after waterflooding and oil displacement by applying vibration excitation with waterflooding. The oil-displacing rate, oil-water distribution, and pressure drop are measured during the oil displacement. The fractional flow is calculated and analyzed. From the experimental results, it can be concluded that applying vibration excitation has positive effects on the oil displacement in terms of increasing the total oil-displacing rate in the micro model flow. The effect is much more noticeable when the oil-water ratio is high. Also, the efficiency of the oil recovery is found sensitive to the acceleration amplitude of the vibration excitation. By comparing the final oil-displacing rate, it is found that applying vibration excitation after waterflooding is more effective in comparing with that applying vibration excitation together with waterflooding.