Calculation for Wellbore Trajectory Measurement Error Incorporating Magnetic Azimuth Correction

With the popularization and application of horizontal wells, cluster wells, and other technologies, higher precision of wellbore azimuth angle measurement is required. Under the condition of magnetic interference, multi-station analysis (MSA) is an effective method for correcting the magnetic azimuth and improving the precision of wellbore trajectory measurement. Compared with the existing error calculation model of wellbore trajectory measurement that only considers the axial magnetic interference correction, MSA considers both the axial magnetic interference and error source correction of the sensor. Therefore, it is necessary to establish an error calculation model of wellbore trajectory measurement suitable for MSA. Based on the error model and covariance propagation rate of the sensor, the weight function of the error source with the directly measured parameters as the independent variables was derived, and an error calculation model of wellbore trajectory measurement incorporating magnetic azimuth correction was established. The influence law of the precision of geomagnetic reference fields on wellbore trajectory errors after magnetic azimuth correction was revealed. The results show that the wellbore trajectory measurement error after magnetic azimuth correction increases with the decrease in the precision of geomagnetic reference fields. It is of practical significance for improving the precision of magnetic azimuth measurement and reducing wellbore trajectory measurement errors by adopting a high-precision geomagnetic model for magnetic azimuth correction.