The Studies On Dynamic Filter Pressing Of Drilling Fluid And Moving Law Of Two-phase Flow Of Solid-liquid

The dissertation studies an experiment device which can separate particles from drilling fluid quickly. The experiment is excited by two vibration motors whose product of mass and radius is equal. And this device adopts a new technique which is composed of swirl, deposition, cross flow and pressure filtration. This dynamic filter pressing device has such feathers: its structure is simple, applying various separate principles, carrying out separation operation continuously and closely. These not only improve segregate efficiency and help to environmental protection, especially, they meet the demand what under-balanced (desert, sea, foam) drilling needed for solid control system. In order to clarify the working mechanism of dynamic filter pressing machine and understand the application of various solid-liquids separate theory on dynamic filter pressing machine, At the same time, provide theories to development and production the new product, this dissertation does some pioneering research work and has completed the following studies.(1) On the basis of the specialties that drilling fluid is incompressible non-Newtonian fluid and its rheologic property is very different from Newtonian fluid, this dissertation analyses and summarize the rheologic model of drilling fluid and gave out a new method of calculation to the rheologic model through experiment. At the same time, dosing well research on the basic property of rock debris, the measures of rock debris and the distributing of particle size which provide theories for choosing screen and choosing the way for separate.(2) Built up the mathematical model of self-synchronization about This dynamic filter pressing device, Make use of the principle of Hamilton ,the self-synchronizing condition and synchronizing state stability condition about The dynamic filter pressing device excited by two self-synchronizing vibration motors are gave out. The coupling mathematical model between the vibration motors and the dynamic filter pressing device is established based on the mathematical model of the three-way asynchronous vibration motors.(3) Based on the structure and the feed of the dynamic filter pressing device, a mathematical method on researching the drilling fluid field in the device is gave out. The boundary condition about the flow field is build up and the mathematical model about the drilling fluid field in the device is set forth. The law of motion of the drilling fluid at the radial direction, the tangential direction and the axial direction is studied, at the same time, the short flow and circulating flow are analyzed.(4)A problem on turbulent flow is studied in the dynamic filter pressing device, the N-S equation and the mixed-model modal are revealed, which can describe the turbulent flow field perfectly. A dominant mathematical mode in the device is build up, and on the base of above, the kinetic law of the debris is discussed.(5)Begin with the interaction between particles and drilling fluid, one after the other, the problem that particles descent at axial direction, descent in centrifugal force field, and get force in thee dynamic filter pressing device is discussed. The condition for centrifugal descent and interferential descent is discussed by making use of the BBOequation, and the final velocity of the particle in the centrifugal force field is educed.(6)The filtered power of the drilling fluids is studied, the law of the dynamic filtering for the lower shear force is analyzed in the dynamic filter pressing device, The Kinetic model of the particle on the filter screen of the device is set up, and a kinetic law of the particle on the vibration filter screen is revealed.The researches on this dissertation are part of the project about the drilling fluids dynamic filter pressing machine sponsored by the Chinese Oil and Natural Gas Company. In conclusion, the theoretical analysis and experimental result show that the relative theoretic research on the dynamic separate model of this equipment is correct and the application for the structure design is suitable .At the same time, the work can contribute to the research of the drilling fluids dynamic filter pressing machine in the future.