Study On Redundant Control Technology Of Steering Drilling Tools

Steering drilling tool is a necessary tool for drilling special structure wells.The reliability of the tool system will directly affect the control effect of steering drilling.As the steering drilling tool is a complex electromechanical integrated system,there are many factors affecting its reliability,and its fault state is not directly observed.How to improve the reliability of the tool system is the key technical problem to be solved urgently in the engineering research of the steering drilling tool.This thesis studies the redundancy technology of the steering drilling tool system.The main work and research results are as follows:1^st.Combined with the engineering practice,and starting from the analysis of the mechanical structure and control system structure of the steering drilling tool,the normal state and fault state of the tool are defined according to whether the tool system can realize its core functions.The fault tree analysis method is adopted to analyze the fault cause of the tool system and then establish its reliability analysis model;2^nd.Based on the reliability analysis of the original tool system,and aiming at the most obvious influence on the system's reliability and the uncomplicated key modules in practical engineering,the redundancy design scheme of tool system is proposed by means of parallel redundancy.Then the fault judgment criterion is designed and the feasible switching control strategy of redundant modules is proposed.Finally,the analysis shows that the reliability of tool system is significantly improved compared with the original ones after adopting the mode of power supply redundancy and controller redundancy3^rd.Completed the preliminary design of redundant controller,and the redundant switched control circuit of the battery power supply and turbine motor power supply,main controller and sub-controller is designed also the other circuit of the controller module.At the same time,the program of signal processing,data acquisition,fault diagnosis and control switch module are written partly.Finally,the system integration and some tests are performed for the redundant systems to proved the rationality of design.These results have practical application value for improving the reliability of downhole tools and solving the key technical problems in the engineering study of steering drilling tools.