The Comparison Study Of The Separation Method Of Potential Field In The Spatial Domain

Gravity and magnetic exploration is one of the geophysical exploration methods.It has been widely used and developed because of its low cost,high efficiency,wide coverage and environmental protection.It is well known that the purpose of exploration is to find useful information about the target body.Gravity and magnetic potential field separation technology is one of the important methods to achieve this goal.So far,many scholars have developed a variety of methods for this technology,which can be divided into spatial domain and frequency domain(wavenumber domain),including the same dimension and same location,the same dimension and different location,and different dimension and same location.In this paper,the comparative study and program design of the separation method of gravity and magnetic potential field in the same dimension and position in space domain are mainly carried out.These methods include trend analysis method,interpolation cutting method,empirical mode decomposition method,minimum curvature method,cross-correlation filtering method and under-balanced filtering method.Firstly,the basic principles of each method and the improvement measures of some methods are given.The corresponding program design is carried out and the program is completed by Fortran 90.Then,by designing a comprehensive theoretical model and selecting different separation parameters to carry out model trial calculation for each potential field separation method.According to the regional and residual anomalies separated,studing the influence of separation parameters on separation effect and abtaining a series of basic conclusions.Finally,according to the results of model trial calculation and the characteristics of the method itself,a comprehensive comparative study of the methods is carried out from five aspects: parameter selection,smoothness of the separation results,the anti-noise ability of the method,the calculation efficiency of the separation method and error of the separation results.It is concluded through the comparative study that the minimum curvature method has the highest comprehensive performance and the best effect,followed by the improved cross-correlation filtering method,and the comprehensive performance of the other methods is similar.Various potential field separation methods are applied to Bouguer gravity anomaly data and RTP magnetic anomaly data in the Bohai Bay of Eastern China to verify the correctness of the method,the practical stability and applicability of themselves.By comparing the characteristics of regional anomalies and residual anomalies separated with the existing regional geological data in the study area,it is found that the iterative sliding trend analysis method,interpolation cutting method,empirical mode decomposition method,minimum curvature method and improved cross-correlation filtering method are adopted for real data processor.The results of these five methods are in good match with those of the existing geological data,while the results of the under-balanced filtering method are poor because of its inherent characteristics of the eight-ring zone,which is difficult too adapt to the actual data with more points and lines.So,Combining with the comprehensive comparison of the methods,this paper considers that the minimum curvature method has more convenient practical operation and good practical application effect,and is more conducive to the widespread use in practical work.