Research On Fault-tolerant Technology Of Vertical Steering Drilling Tool Attitude Measurement

With the development of oil and gas mining technology,more and more underground electronic equipment is used.However,these electronic devices are prone to malfunction due to the influence of strong vibration near the bit and the high temperature environment in the downhole during drilling.How to improve the reliability of underground electronic equipment is the key in drilling engineering.In this paper,the redundant sensor structure is applied to propose the attitude fault-tolerant measurement method of drilling tools,and the effectiveness of the method is verified by simulation experiments.The main work and research results are as follows:1.The measuring principle of three-axis gravity acceleration sensor and fluxgate sensor for drilling tool attitude is analyzed,and the problems of attitude parameters "mismeasurement" and "unmeasurable" in near vertical state of drilling tool are discussed.Aiming at improving the measuring accuracy of the system,the measuring error caused by drilling tool rotation and drilling tool vibration is processed by speed compensation method and filter method respectively.2.In this paper,a redundant system of attitude measurement of drilling tools composed of seven sensors,such as three-axis gravity acceleration sensor,three-axis fluxgate sensor and rate gyroscope,is proposed.The relationship between sensor signals and measured parameters is analyzed.An inverse estimation algorithm of gravity acceleration vector based on fluxgate measurement signals is given and the formula for solving attitude parameters of drilling tools based on the inverse estimation is deduced.Aiming at the four kinds of fault types in the measurement system,the fault judgment criterion and fault tolerant measurement method are put forward respectively.3.The hardware design of signal processing circuit,system power supply and peripheral interface circuit of main control chip is completed,and the corresponding software program is designed.By setting specific fault conditions,the principle prototype is tested.The experimental results show that the fault-tolerant measurement system can still complete the attitude calculation of drilling tools under the four sensor faults,such as fluxgate fault,single-branch meter fault and three-branch meter fault,which verifies the correctness of the fault-tolerant measurement scheme.The research results of this paper can provide a theoretical reference for judging the fault of measuring sensor,constructing redundant measurement system and establishing fault-tolerant measurement method to improve the reliability of drilling tool attitude measurement system.