Research On Equilibrium Compensation Method Of Instrument Attitude Correction Matrix Error

With the continuous development of energy economy,oil wells in less difficult areas have been gradually depleted,so oil drilling has to expand to deep water,deep strata and unconventional areas,where the complex geological conditions make oil extraction much more difficult,forcing the traditional oil drilling technology to be constantly innovated.Rotary guided drilling technology is the most mature and widely used drilling technology in the world.The development and innovation of downhole attitude control technology and borehole trajectory tracking control technology in rotary guided drilling technology is in line with the current trend of oil field development to unconventional areas.Accurate measurement of downhole drilling tool attitude parameters is a necessary prerequisite for downhole attitude control and real-time tracking borehole trajectory.The existence of various errors in the attitude measurement process seriously affects the accuracy of the drilling tool attitude measurement,so this paper studies the error correction of the drilling tool attitude measurement system.Based on the attitude measurement principle of the strap-down inertial navigation system,the tri-axial accelerometer and magnetometer are used to form the attitude measurement system to simulate the downhole attitude measurement of drilling tools.By analyzing the accelerometer output signal characteristics and measurement error sources,the attitude matrix error model is established,and the absolute error calculation formula for each attitude angle is derived.The error model of the conventional maximum correction matrix is established and analyzed.On this basis,a novel balance correction method,defined as equivalent interval balance correction(EVBC),is proposed to achieve the accurate measurement of attitude angle through balancing the correction matrix parameters including various measurement errors.A drilling tool attitude simulation test system was built to obtain the drilling tool attitude parameters at the low inclination position,and the test data were calibrated using the conventional maximum correction method and the EVBC method respectively.The calibration results show that the proposed EVBC method can effectively eliminate the systematic errors of the conventional maximum correction method and achieve the accurate measurement of inclination angle and tool face angle at the low inclination position.