Sensor orthogonal calibration method for oil drilling measurement

Abstract

The invention discloses a sensor orthogonal calibration method for oil drilling measurement. The method comprises the following steps of: selecting an acceleration sensor and a flux gate which conform to use requirements, arranging the acceleration sensor and the flux gate on an instrument framework, and simply regulating to enable the coordinate axes of an instrument coordinate system to be basically coaxial with the sensing shaft of the sensor; then arranging instruments into 12 specific gestures according to an established mathematical model, so as to obtain orthogonal calibration coefficients of the sensor; calculating one group of orthogonal calibration coefficients at an temperature interval under a heating state till the specific temperature; carrying out temperature compensation on orthogonal calibration coefficients by utilizing nonlinear fitting; and enabling the calibrated sensing shaft of the sensor to be accurately coaxial with the coordinate axes of the instrument coordinate system by virtue of software. By utilizing the method, the calibrated sensing shaft of the sensor is accurately coaxial with the coordinate axes of the instrument coordinate system by virtue of software, thermal compensation is realized, and the original instrument calibration method is improved.

Description

technical field [0001] The invention belongs to the field of petroleum drilling engineering, in particular to a method for orthogonal calibration of a sensor used for petroleum drilling measurement. Background technique [0002] At present, Measurement While Drilling (MWD) and Logging While Drilling (LWD) systems have become an indispensable part of petroleum drilling engineering, and the acquisition of downhole data is even more important. In geological exploration, in order to be able to determine the lateral dip and dip azimuth of the formation, it is necessary to continuously measure the dip and dip azimuth of the wellbore and the azimuth of the downhole tool as a reference mark. When carrying out secondary drilling or drilling horizontal wells, it is necessary to know the well trajectory and the position of the drill bit to adjust the next drilling direction. Therefore, whether it is after the completion of the well or during the drilling process, high-precision contin...

AI Technical Summary

Problems solved by technology

In practice, even if the 3 acceleration sensors and 3 fluxgate sensors are fine-tuned, due to installation reasons, errors in measurement vision, etc., deviations caused by non-orthogonal sensitive axes cannot be avoided

[0004] But in fact, limited by the processing technology and installation technology level, the three sensitive axes in the actual sensor cannot be strictly orthogonal, and the three-axis sensitivity and other electrical properties cannot be completely symmetrical.

In addition, there are also influences such as zero drift and internal interference of the sensor, which make the three-axis sensor have a large error between the measured value and the actual value of the same gravity field or magnetic field in different forms.

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