变阶数滑动趋势分析及其应用

Order-variant sliding trend analysis and its application

1. 西安地质学院物探系, 西安710054;2. 地矿部区重中心

Department of Exploration Geophysics, Xi'an College of Geology, Xi'an 710054

本文引用正交变换法将趋势面分析中的系数矩阵化为对角阵, 避免了求解病态方程组, 提高了解的精度。同时正规方程组可变为十分容易求解的一次方程组, 因而加快了求解速度。采用自动改变滑动窗口, 改变趋势面阶数的办法, 解决了因一次性选取固定趋势面而出现虚假异常的难题。将该方法应用于某含油气沉积盆地上高精度重力细测微弱异常的识别及古塔山精确位置的求取, 取得了满意的效果。

In this papcr, we make use of the orthogonal transformation method to transform the coefficient matrix of trcnd surface analysis to a diagonal matrix so as to avoid solving ill-conditioned system of cquations and improve the precision of solution, Meanwhile, the normal equations are transformed to a first-ordcr system of cquations which is very casy to solve,thcrefore, the solving process is sped up. Furthcr, the order-fixed trend surface analysis which is responsible for false anomaly is replaeed by sliding window and order-variant trend surface analysis. As a result, the application of the method in recognizing weak anomalies of high accuracy gravity survey and determining the accurate position of buried hill in oil-bearing sedimcntary basin has brought forth sat isfactory results.