The Profiles Modification And Parameterized Modeling Of Shaft-housing Pairs Of Three-thread PDM

With the unprecedented increase of domestic and international market demand for petroleum products,and the rapid development of oil drilling industry,screw drill has gradually replaced other types of downhole power drill,and become the most used downhole power drill in the oil drilling industry.However,with the development of deep and ultra deep wells,the performance and service life of the screw drill are required to be higher,and the advantages and disadvantages of the screw bushing pair have become the focus of the study of the screw drill,and gradually attracted the attention of the relevant personnel.In this paper,the problems of poor meshing performance and service life reduction caused by bushing "burning" of the screw drill are analyzed,and the theoretical profile of the screw drill is modified according to the research,so as to make it more meet the actual needs of the site.This paper first describes the most widely used short pair cycloid equidistant line formation principle and the optimization method of line structure parameters,and according to the optimization method,the optimization of 3:4 head screw drill structure parameters is completed,which provides a certain theoretical basis for the follow-up chapters.This paper focuses on the study of profile correction of 3:4 conventional wall thickness bushing and equal wall thickness bushing.Through the thermal mechanical coupling analysis of drilling fluid pressure and ambient temperature of the two bushing models,the profile correction equations of the inner contour curves of the two kinds of bushing are established by using the function fitting method,and the working depth,eccentricity coefficient,eccentricity coefficient and temperature are analyzed The influence of the selection of the amplitude coefficient and the thickness of the bushing on the profile correction equation is analyzed;The thermal mechanical coupling finite element model of screw bushing pair is established,and the finite element analysis of the bushing before and after modification is carried out by using the finite element model,which proves that the bushing after profile modification can effectively reduce the temperature rise and maximum stress of the bushing when working underground.The parametric modeling window application program of screw and bushing after profile modification was developed,including the optimization of profile structure parameters,the calculation of screw drill output parameters,and the parametric modeling of screw and bushing;The shrinkage deformation analysis of the rubber bushing in the process of die casting was completed,and the application program of parametric modeling window was developed for the bushing mandrel after profile modification.