In exploration for tight oil, the content and saturation of hydrocarbon in the tight reservoir is a key factor for evaluating the reserve. Therefore, it is necessary to study the geological history of hydrocarbon accu...In exploration for tight oil, the content and saturation of hydrocarbon in the tight reservoir is a key factor for evaluating the reserve. Therefore, it is necessary to study the geological history of hydrocarbon accumulation and the tight oil charging process. However, kinetic models used for petroleum development are not applicable for petroleum exploration. In this study, a static resistance model[ is proposed after analyzing resistances in ultra-slow flow in porous media. Using this model, the disco^atinuous pattern of oil charging is reproduced through incompressible Navier-Stokes equations, the phase field method and the finite element method. This study also explains macroscopic percolation behavior with microscopic flow mechanisms and discusses some issues in ultra-slow flow in a micro/nano pore-throat network. The resistance analysis reveals that capillary resistance and dissipation resistance are dominant factors in the mechanism of oil accumulation in tight reservoirs. Numerical simulations show that pressure thresholds exist and result in discontinuous oil charging. Generally, it is proven that the static model is more applicable than kinetic models in describing oil accumulation in tight reservoirs.展开更多
The static dent resistance performance of the aluminum alloy double-curved panel formed using viscous pressure forming (VPF)was studied by finite element analysis,which mainly considers the forming process conditions....The static dent resistance performance of the aluminum alloy double-curved panel formed using viscous pressure forming (VPF)was studied by finite element analysis,which mainly considers the forming process conditions.The whole simulation consisting of three stages,i.e.,forming,spring-back and static dent resistance,was carried out continuously using the finite element code ANSYS.The influence of blank holder pressure(BHP)and the drawbead on the stiffness and the static dent resistance of the panels formed using VPF was analyzed.The results show that the adequate setting of the drawbead can increase the plastic deformation of the double-curved panel,which is beneficial to the initial stiffness and the static dent resistance.There is an optimum BHP range for the stiffness and the static dent resistance.展开更多
The static flow resistivity is a fundamental parameter for measuring and classifying the sound absorption behavior of various types of materials. Several methods have been developed for measuring the static flow resis...The static flow resistivity is a fundamental parameter for measuring and classifying the sound absorption behavior of various types of materials. Several methods have been developed for measuring the static flow resistivity acoustically. Most of these methods cannot be implemented directly in the standard tubes which are widely used for measurements of sound absorption coefficients and impedance as defined in ISO 10534.2. The accuracy of the proposed method and the tube is verified through finite element analysis and the feasibility to determine the static flow resistivity is validated through experiments. It is validated that the accuracy of the proposed method is highly dependent on the position of the acoustic center of the measurement microphones and the accuracy can be enhanced by increasing the back cavity depth and/or decreasing the measurement frequency.展开更多
基金supported by the Chinese Major National Scientific and Technological Program (2011ZX05001)Chinese Postdoctoral Fund (2013M540114)
文摘In exploration for tight oil, the content and saturation of hydrocarbon in the tight reservoir is a key factor for evaluating the reserve. Therefore, it is necessary to study the geological history of hydrocarbon accumulation and the tight oil charging process. However, kinetic models used for petroleum development are not applicable for petroleum exploration. In this study, a static resistance model[ is proposed after analyzing resistances in ultra-slow flow in porous media. Using this model, the disco^atinuous pattern of oil charging is reproduced through incompressible Navier-Stokes equations, the phase field method and the finite element method. This study also explains macroscopic percolation behavior with microscopic flow mechanisms and discusses some issues in ultra-slow flow in a micro/nano pore-throat network. The resistance analysis reveals that capillary resistance and dissipation resistance are dominant factors in the mechanism of oil accumulation in tight reservoirs. Numerical simulations show that pressure thresholds exist and result in discontinuous oil charging. Generally, it is proven that the static model is more applicable than kinetic models in describing oil accumulation in tight reservoirs.
文摘The static dent resistance performance of the aluminum alloy double-curved panel formed using viscous pressure forming (VPF)was studied by finite element analysis,which mainly considers the forming process conditions.The whole simulation consisting of three stages,i.e.,forming,spring-back and static dent resistance,was carried out continuously using the finite element code ANSYS.The influence of blank holder pressure(BHP)and the drawbead on the stiffness and the static dent resistance of the panels formed using VPF was analyzed.The results show that the adequate setting of the drawbead can increase the plastic deformation of the double-curved panel,which is beneficial to the initial stiffness and the static dent resistance.There is an optimum BHP range for the stiffness and the static dent resistance.
文摘The static flow resistivity is a fundamental parameter for measuring and classifying the sound absorption behavior of various types of materials. Several methods have been developed for measuring the static flow resistivity acoustically. Most of these methods cannot be implemented directly in the standard tubes which are widely used for measurements of sound absorption coefficients and impedance as defined in ISO 10534.2. The accuracy of the proposed method and the tube is verified through finite element analysis and the feasibility to determine the static flow resistivity is validated through experiments. It is validated that the accuracy of the proposed method is highly dependent on the position of the acoustic center of the measurement microphones and the accuracy can be enhanced by increasing the back cavity depth and/or decreasing the measurement frequency.
