The Design And Analysis Of Magnetic Field Of The Drilling Fluid Magnetizer

Drilling fluid magnetizer is a magnetic tool used in the process of drilling,which can fix the magnetized permanent magnet and magnetize the drilling fluid.It is installed to down hole.It can produce uniform magnetic field at the center channel,which is perpendicular to the direction of fluid flow.When drilling fluid runs through,it can be magnetized.The magnetic drilling fluid has lower viscosity and shear force and has the capacity of suppressing producing mud,preventing formation swelling and protecting the reservoir.It is a new technology to magnetize drilling fluid.Firstly,the magnetization mechanism of drilling fluid is analyzed.The effect of magnetic field on the performance of drilling fluid is studied.Especially,the effect on several important rheological parameters of drilling fluid,including the shear stress,the plastic viscosity and the apparent viscosity is analyzed.On the basis of theory,a numerical method is proposed to calculate the magnetic fluid of cylindrical permanent magnet in space.Secondly,two kinds of drilling fluid magnetizing devices are designed,based on the magnetization mechanism of drilling fluid.Finally,the strength analysis and magnetic field analysis of the drilling fluid magnetizer are performed with ANSYS software.During the strength analysis,the effects of pulling force,inner pressure and torque,the axial gap,radial gap and hole size of permanent magnets are studied on strength.Through strength analysis,the optimal parameters of magnetizer are determined.Through the analysis of two-dimensional magnetic field,magnetic field strength and distribution of magnetic field lines are got.And through the analysis of three-dimensional magnetic field,the variation of magnetic field strength with the change of axial and radial gap of permanent magnets is got.At the end,the experiment is performed to verify the accuracy of results of numerical calculation and finite element analysis.