The Structural Design Of CO₂ Pressurized Closed-system Sand Blender Used On Solid-liquid Mixing

With the application and development of liquid CO₂ fracturing technology,It isnecessary to design a matching fracturing equipment for oil field well.It is one of the key technologies to develop a sealed mixed sand equipment to achieve the mixing of CO₂ and sand in the fracturing pump.Forthemore,this paper proposes a pressurized closed-system sand blender on the basis of the principle of venturi design,and it will effectively improve the low viscosity of liquid CO₂,and the disadvantage of carrying capacity is poor,with high shear flow strength mixed mix liquid CO₂ and the mixture of fracturing fluid.That is the purpose of this pressurized closed-system sand blender research.In this paper,based on the situation of domestic solid-liquid mixed equipment and the gap with foreign advanced products,at the present of the practical need of fracturing technique as a starting point,the key for the overall design of solid-liquid mixed equipment mixed workspace.Based on Venturi's principle,the model of CO₂ closed sand mixing device was established in this study.The finite element Fluent software was used to simulate the flow of fluid and the effect of mixing in the closed sand mixing plant.Under the condition of processing parameters such as handling quantity and sand carrying ratio,the influence of three structural factors,such as throat diameter D,throat length L and diffusion angle beta,on the mixing effect of CO₂ closed sand mixing device are emphatically analyzed.The pressure distribution in the mixing plant and the distribution of sand volume in the outlet end are compared and analyzed under different influence factors.Finally,the mixed sand assembly is obtained.The best structural parameters are set up to provide the method and basis for the structural design of liquid CO₂ closed sand mixing device.According to the optimum structural parameters selected,the three-dimensional map of the closed sand mixing device was drawn,and the sanding material adapted to the low temperature environment of the liquid CO₂ was selected,and the strength analysis of the mixing device was carried out based on the finite element software.That is the physical solution model is created in Gambit,and the grid is divided by different regions and different density methods.The fluid domain model is introduced into the mixing device pipeline model,and the stress and strain of the fluid solid coupling relationship is established to analyze the closed sand mixing device.Based on the principle of equal strength,the optimal scheme of the closed sand mixing device in different wall thickness and different material selection is analyzed based on the non-influence of the fluid flow path.The optimal scheme is to adopt single factor analysis method,and choose the optimal pressurized closed-system sand blender structure of 8mm?7mm?6mm and 5mm wall thickness.At the same time,it was determined that the optimum low-temperature materials were selected for the optimum cryogenic materials of the three different cryogenic materials Q345e,16MnDR and15MnNiDR,When the wall thickness is the best size.The optimum cryogenic material was selected,and the optimum design scheme of pressurized closed-system sand blender was obtained.