Research On Drilling Fluid Flow Law Of Circulating Screen Negative Pressure Vibrating Screen

Shale shakers are the first phase of a solids control system on a drilling rig and are used to remove large solids(cuttings)from the drilling fluid.At present,the environmental problems caused by the development of the petroleum industry have become increasingly prominent.In response to the stricter environmental protection requirements,the new type of shale shaker,namely circulating screen negative pressure shale shaker,aims to improve processing capacity is proposed in this thesis with the features of circulating screen and negative pressure.In this paper,first of all,the working principle of the circulating screen shale shaker with negative pressure was introduced.Then,the overall implementation plan and the detailed structure of the shale shaker were designed.Also,the screening process of the drilling fluid was simulated based on the new shale shaker.Finally,the processing capacities of the shale shaker under various conditions were studied based on the simulation results.The detailed contents of the thesis are as follows:(1)The structure design and parameter calculation of the proposed circulating screen negative pressure shale shaker were completed,which includes the design of the chain drive structure and the excitation system.Besides,the physical model of the shaker was also established by three-dimensional software.(2)The basic theories and computational fluid dynamics models involved in the screening process of the shale shaker was analyzed and determined,which includes porous media model,multi-phase flow model,turbulent flow model.Besides,the equations of motion of the drilling fluid along the screen surface were also derived.(3)The flow field calculation model of the shale shaker was established based on its working principle and simplified physical model by using the ICEM software.In the analysis process,the layer of solid particles on the screen surface and the movement of the vibrating screen were modeled by porous media layer and dynamic mesh technology respectively.The processing capacity of the new shale shaker was obtained based on the distribution and penetration situations of particles under different negative pressure conditions.(4)The process capacity of the new shale shaker was studied under different drilling fluid viscosities,drilling fluid densities,screen mesh numbers and screen circulation speeds.It was found that the processing capacity of the shale shaker decreases with the increase of the viscosity of the drilling fluid and the number of mesh.Also,the processing capacity of the shale shaker increases with the increase of the density of drilling fluid,the size of particle and the frequency of vibration.The research results of this paper provide a theoretical basis for the development and application of the new type of shale shaker.