Magnetic Interference Correction Method for Dynamic Measurement of Steering Head and Its Application

During the operation of the rotary steering system， the magnetic interference faced by the steering head when performing dynamic measurement tasks mainly comes from two aspects： one is the magnetic influence of the internal current fluctuation of the M30 bus， and the other is the external magnetic interference in the real-time environment of the drilling operation. Specifically， when the current intensity of the M30 bus is greater than 1 A， an interference magnetic field will be generated， which directly challenges the magnetic measurement accuracy of the steering head. Meanwhile， the elements such as bit and mud flow involved in drilling further aggravate the degree of magnetic interference， which not only significantly reduces the magnetic measurement accuracy of the steering head， but also may mislead the judgment of the azimuth gamma and resistivity imaging areas， leading to engineering errors. To address the above problems， a magnetic interference correction scheme for the steering head was innovatively proposed. First， magnetic interference regression analysis was conducted on the current of the M30 bus. Then， by means of integrating attitude measurement principles with multi-point analysis techniques， the single-point correction and the multi-point correction model optimized by an adaptive genetic algorithm were creatively applied to conduct deep and precise calibration on the three-axis fluxgate sensor. Analysis on the data obtained after application in DengX well shows that this method reduces the dynamic magnetic measurement azimuth angle error of the rotary steering system by 85%. Further application in multiple well clusters in Huabei Oilfield and Changqing Oilfield shows that the azimuth angle consistency of static magnetic measurement is improved by 13%. These application practices prove the effectiveness of the magnetic interference correction method in significantly improving the dynamic magnetic measurement accuracy of rotary steering.