Study On High Resolution Density Inversion Method Of Three-dimensional Gravity Gradient Tensor

Gravity anomaly is a comprehensive reflection of the underground density difference.According to the anomaly characteristics,the underground density distribution can be inverted.In order to improve the skin effect of the inversion results,the density inversion method adopts the depth weight function iteration method to obtain the final results.However,the existing weight functions have the same values at the same depth,so the resolution is low.It is difficult to obtain accurate inversion results in geological bodies with closer distance or deep buried depth.In this paper,a density inversion method based on normalized anomaly weight is proposed to obtain high resolution inversion results.The application effect of Gravity Tensor Inversion in improving the resolution of inversion results is studied by theoretical model test.By introducing gravity tensor density inversion,the resolution of inversion can be improved through data combination of different parameters,and the difference between the inversion results of gravity horizontal tensor data and the inversion results of full tensor data is compared,which provides a basis for the development and practicality of Gravity Tensor gradiometer.An inversion scheme for air-ground gravity data is established,and the high resolution density inversion results are obtained by using the vertical variation characteristics of the data,and the cooperative inversion methods for anomalies with different scales and characteristics of different observation surfaces are realized.The effectiveness and practicability of the model test method provide technical and theoretical support for joint air-ground exploration.In view of the low resolution of density inversion method,a density inversion method of gravity normalized anomaly weight function is proposed.The normalized results of anomalies at different heights are obtained by continuation as weight function instead of the conventional depth weight function,which improves the shortcomings of previous methods that have no change in the same depth weight function and can effectively improve the resolution of inversion results.Model testsshow that the density inversion method based on normalized anomaly weight function has higher horizontal and vertical resolution,and is less disturbed by noise.The results show that the inversion results of gradient anomaly weight function have higher horizontal resolution than those of the original anomaly.The proposed method is applied to the interpretation of the actual gravity anomaly in Shandong Province and the specific distribution of iron ore is obtained.Joint gravity tensor density inversion can obtain higher resolution density inversion results by using multi-parameter data characteristics.The resolution of anomaly inversion measured by horizontal tensor gradiometer developed in China is tested and compared with that of full tensor inversion.The model test results show that the inversion results of gravity horizontal tensor anomalies also have high resolution,which is close to the inversion results of full tensor.Therefore,in the subsequent instrument research and development,emphasis should be placed on improving the accuracy,followed by the development of full tensor instruments,which provides the basis and technical support for the development and practicality of tensor instruments in China.With the development of aeronautical geophysical technology,some regions have both aeronautical and terrestrial gravity data.Through the joint inversion of air-ground data,the resolution of the previous ground inversion results can be improved by using the vertical data variation characteristics.Aiming at the problems of flight altitude and layers in air-ground coordinated inversion,the data acquisition method of air-ground coordinated inversion is discussed by correlation analysis and singular value decomposition,which can guide air-ground joint exploration and provide more effective data combination for high resolution density inversion.For inversion of gravity anomalies in undulating terrain,a curved surface inversion technique is proposed,which is more efficient than the direct inversion.The theoretical model shows that the method can effectively obtain the density distribution of field sources,and the effect of air-ground coordinated inversion with different scales is tested.The research of the method technology can effectively promote the development of actual data acquisition methods.