磁性套管中磁测斜仪误差建模分析

在利用磁测斜仪测量钻井方位角时,铁磁性套管会对放入其中的测斜仪产生磁屏蔽作用,严重影响了方位角的解算精度。针对该问题,利用ANSYS软件对磁测斜仪环境磁场进行仿真,从而建立磁测斜仪误差模型;并用牛顿迭代法对钻具方位角和套管磁屏蔽系数进行快速解算。最后针对该优化算法的误差校准效果进行数学仿真分析。仿真结果表明,相比于传统解算算法,该方法能够更准确地解算出钻井的方位角。同时,在存在随机白噪声干扰的情况下,当信噪比较低时可以通过多次测量求平均值来减小解算误差。

Error analysis of magnetic inclinometer in magnetic sleeve

In the use of magnetic inclinometer measuring drilling azimuth, magnetic iron pipe can generate a magnetic shielding effect to the inclinometer in them, seriously affecting the solution precision of azimuth. To solve this problem, the magnetic environmental of magnetic inclinometer is analysed by ANSYS, the mathematical model of casing is established. The Newton iteration method to calculating azimuth angle and the magnetic screening coefficient of the casing is put forward. Finally, the simulation analysis for the algorithm shows that this method can calculate the drilling azimuth more accurately than the traditional solution algorithm. The calculation error can reduced by repeated measurements of average in the low SNR.