融合整段多项式和插值的井下姿态非线性校正

Non-linear correction of downhole attitude by fusing piecewise polynomial and interpolation

井下工具姿态角的静态解算非常依赖三轴传感器,但测量过程中系统误差会带来固有失真,需要对系统误差进行充分补偿以获取准确的姿态角信息。根据姿态误差传递模型,提出将不同姿态下三轴传感器的输出轨迹划分为不同的区域,融合整段多项式和样条插值方法来近似不同姿态下的校正矩阵,从而对系统误差进行充分补偿。最后,采用高精度标定实验装置对所提出方法进行精度检验。在井斜角为3.006°时统计姿态角误差(均值±标准差),其中方位角误差为0.0109°±0.0794°,井斜角误差为0.0012°±0.0021°,工具面角误差为0.0057°±0.0399°。姿态角误差统计验证实验结果表明,所提出方法具有较好的姿态角误差补偿效果,可有效解决姿态解算过程中的非线性问题,可以进一步提高井下工具姿态的整体精度。

At present,the static calculation of downhole tool attitude angle relies heavily on triaxial sensors.However,system errors in the measurement process may lead to inherent distortion,so it is necessary to fully compensate the system errors in order to get accurate attitude angle information.Based on the attitude error propagation model,it is proposed to divide the output trajectory of the triaxial sensor at different attitudes into different regions,and approximate the correction matrix at different attitudes by fusing piecewise polynomial and spline interpolation,so as to fully compensate the system errors.Finally,the precision of the method proposed above is verified by high-precision calibration experimental device.When the well inclination angle is 3.006°,(mean±standard deviation)of the attitude angle error are calculated,among which the error of azimuth angle,well inclination,and tool face angle is 0.0109°±0.0794°,0.0012°±0.0021°,and is 0.0057°±0.0399°,respectively.The verification test results of attitude angle error statistics show that the proposed method is characterized by good compensation effect on attitude angle errors,which can effectively solve non-linear problems in the attitude calculation process,thus improving the overall precision of downhole tool attitudes.