航磁梯度数据的曲化平方法及应用

Method of Aeromagnetic Gradients Anomaly Continuation from Undulate Surface to Plane and Its Application

将插值-迭代法移植到航磁梯度数据的曲化平计算中,利用长方体模型验证方法的有效性和计算精度.计算结果表明,利用插值-迭代法对梯度异常进行曲化平可以达到较好的精度,平均相对误差小于7%.将曲化平处理前后的梯度数据分别应用于解析信号法和欧拉反褶积法,对比结果表明,利用曲面上梯度计算的解析信号极大值明显偏离了长方体磁源的中心位置,对长方体边界反映不明显,而利用化平后的梯度计算解析信号能够更好地反映场源体的边界和中心位置;利用曲面上的梯度进行欧拉反演的结果比较分散,而曲化平后的梯度数据反演的结果则比较集中,可以较好地反映出长方体场源四个角点的位置.以上结果证明梯度数据经过曲化平处理后可以改善这两种解释方法的应用效果.

The interpolation - iterative method is applied to aeromagnetic gradient anomaly continuation from un-dulate surface to plane in this paper, and a prism model is constructed to demonstrate the effectiveness and accu-racy of the method. The calculated results show that the technique has good accuracy and that all mean relative errors of computed results are less than 7%. Gradient anomalies on undulate surface and gradient anomalies after continuation from undulate surface to plane are applied to analytic signal calculation and Euler deconvolution method respectively. Comparisons of the results indicate that the maxima of analytic signal calculated by gradient anomalies on undulate surface deviate obviously from the center location of the prism magnetic source, and that the position of prism boundaries are not clear. However, the analytic signal calculated by gradient anomalies after continuation from undulate surface to plane can be successfully used to estimate the center and boundaries posi- tion of prism. The solutions of Euler deconvolution method calculated by gradient anomalies on undulate surface are dispersive while the solutions calculated by gradient anomalies after continuation from undulate surface to plane are relatively clustering, and can outline clearly the positions of prism comers. The results demonstrate that continuation from undulate surface to plane processing of gradient anomalies can improve the application effect of analytic signal and Euler deconvolution technique.