Application Of Impedance Inversion In Coal Thickness Prediction

With the large-scale mechanized mining equipment used in coal mining, coal thickness may affect the roadway layout and the progress of coal production. The previous interpretation of coal thickness without full use of existing seismic and geological data, In order to improve the accuracy of the interpretation of coal thickness, provide a more accurate geological information, especially the coal seam thickness, Here we introduce the impedance inversion method to predict coal thickness.This paper describes the basic method of inversion, include the integral inverse, recursive inversion and model inversion methods, and then introduced their advantages and disadvantages. Amang many logging constrained inversion methods,this paper discussed the STRATA wave impedance inversion method,which effectively combine high vertical resolution logging data and seismic data characterized in high lateral resolution together to achieve the purpose of identification of the coal seam.This study selected 3D seismic data of three different geological conditions to do wave impedance STRATA inversion: Hu Baowang Area, small seam angle, simple structure; Hong Guozi, dip seam angle, general structure; Da Fosi area,small angle of coal seam, Simple construction, thin to thick coal seams, high grade of coal seam thickness. By logging pretreatment, layer explaination, wavelet extraction, layer calibration, modeling and correction, coal seam thickness calculation,etc. a series of operations, We get some ideal wave impedance data and coal seam thickness trends of the three working areas. Analyzing the actual situation in each work area and the inversion results obtained, it is resulted that, STRATA inversion can get good quality result, only when the coal and rock have obvious difference in acoustic impedance, and have a good record of seismic reflection. If the fault and fold structures exist, we could explain the coal seam thickness by control layer .