Investigation Of Particles Behavior And Distribution Under Gravity During The Filtration Of A Slotted Filter Withaccumulation Chamber: CFD Simulation And Experimental Validation

Filtration with installed well screens(filters) is very important not only for the quality of filtrate fluid but also for the lifetime of downhole tools, pumps and well, as the fluid flow with solid particles is a cause of erosion damage. Slotted filter is widely used today in oilfield as an effective and low cost way of extracting crude oil. A performance of a slotted filter is significantly influenced by its structural parameters, such as, slot shape, geometry, width and number of slots. Parameters such as a size and shape of solid particles and their behavior in the filtration flow have also influence on performance of filters.The aim of present research is to investigate the flow structure at the vertical cross-section of the well with installed slotted filter with accumulation chamber. Furthermore, the solid particle behavior and distribution under gravity field are examined. This knowledge is fundamental for an adequate design of well filters and other downhole tools. In addition, the work effectiveness of slotted filter with chamber is tested when the slots width bigger(more than 3 times) than the size of solid particles at the flow velocity 0.048-0.48 m/s. It can be proposed that it decrease the flow resistance at filtration surface and increase a lifecycle of a slotted filter. Solid particles can be separated under gravity force.The widely used today type of well filters are observed, its advantages and disadvantages. The procedures of well filter design and selection are demonstrated. The geometry and main hydraulic characteristics of slotted filter with accumulation chamber is calculated and a scheme of its installation in the well is presented. A mathematical description of the forces acting on the solid particle in the filtration flow is built and three cases of particle motion in the flow are considered. This analysis is based on the Newton’s law of motion.The defined aim of this research is experimentally investigated and numerically confirmed at various flow conditions. A slotted filter with accumulation chamber is tested in an experimental setup. A flow structure is visualized experimentally and recorded by a high speed video camera. Vectors of solid velocity field are computed by PIV technique. The flow conditions are producing b y changing inlet velocities in 0.048-0.48 m/s. The CFD(Computational Fluid Dynamics) simulation is implemented to verify the experimental results. A model of the well with installed slotted filter is created and meshed by Gambit 2.2 and simulated in ANSYS FLUENT 13.0 software. A two-phase Eulerian model and standard k-e model per phase are used in CFD simulation. Solid vectors velocity field and solid volume fractions at steady and unsteady state conditions are studied at the investigated cross-section area. A performance of slotted filter with chamber is determined through the solid volume fraction at the outlet area. The solid volume fraction in the filtrated fluid depends on the magnitude of the inlet velocity. The accumulations of solid volume fraction in the chamber at various inlet velocities reveal that the chamber can be used as additional filtration function in slotted filter. It’s due to the work of gravity force on the solid particles. A good agreement is obtained between the CFD simulation and experimental results. However, there are some small differences due to the error of CFD simulation and PIV process.This research provides understanding of flow structure in the well with installed slotted filter with accumulation chamber, solid particles behavior and distribution under gravity field. Furthermore, this study reveals that the slotted filter can work effectively even if slot’s width is bigger(more than 3 times) than the size of solid particles. Then, based on obtained results, some recommendations are given for effective well filters design. It is also possible to conclude that the results presented in this research can be used in man y industries for instance, petroleum and water production, water purification etc.