Design And Performance Study Of The Split-tupe Six-arm Caliper Logging Tool

In order to adapt to the increase of high-angle wells and horizontal wells in China in recent years,this paper points out to the problems of insufficient measurement accuracy in the special construction of traditional vertical well logging tools.From the five aspects of opening mode,balancing device,sealing,power system and sensor,a new type of split six-arm caliper tool was designed.In order to further improve the transmission performance the push system,the complex vector method and the matrix method are applied to establish the kinematics model of the pushing system to open and measure the two motion states.Dynamic dynamics method is used to establish a dynamic analysis model for the two motion states of the pushing system.Based on the Adams software,the Adams/View module is used to establish the opening and measuring geometric model of the pushing system.The regularity curve of the displacement,velocity and acceleration of the components with time is obtained,and the force of each component is obtained.The situation assisted analysis and verification of the motion law of the system,which provided a theoretical basis for the optimization design and performance improvement of the caliper tool.In view of the fact that the caliper cam of the caliper tool of China currently adopts the eccentric arc profile,it has the problems of large dynamic load,poor force transmission effect and short instrument life.A parametric model of the push-arm cam based on the involute,Archimedes spiral and eccentric arc is established,and the motion characteristics and mechanical efficiency of the three push-arm cams are analyzed.The research shows that the structure of the involute type pushing arm can improve the force characteristics of the piston rod,reduce friction and wear,and further improve the measurement accuracy in the pushing system.Therefore,the caliper tool is more adaptable,more precise,and has a longer life.