Geology Analysis Of Coal Seam Wave Impedance Inversion In The Southeast Margin Of Songliao Basin

Recently as the speedy development of the coal seam in Jinlin Province, there are notenough known coal resources to meet the society needs. However, the conventional seismicprocessing and interpretation methods cannot be used efficiently to explore new resources.Therefore it is important to develop new seismic methods that can quantitatively todetermine the possible existence zone of coal seam and its burying depth and horizontallocation.The target area in this study is located in the southeastern margin of Songliao basinwhere transportation system is highly developed and there are many big cities. It is vital forthe economical development of Jinlin province and the better development of coal industryif one or several zones of high concentration of coal seams can be identified. We developeda new set of seismic processing and interpretation methods that are more suitable for theSongliao basin. The data includes high-resolution seismic data and borehole data. Themethods include multiple-parameter seismic wave impedance inversion, seismic phaseanalysis. The methods were applied to several areas and we found new coal seam in Jilinarea.Seismic exploration has been evolved from characterizing the geological structure torecognizing rock types and quantifying rock properties. Seismic inversion is a product ofthis evolving process. It has been a hot topic by applying the seismic method in exploringcoalfields. Because the structural characteristics of the coal seams are generally obscure,the conventional seismic exploration that emphasizing structures is not suitable. Comparedto the wave amplitude that reflects the interface, the wave impedance is more suitable forcharacterizing the reservoir layers. Furthermore, the wave impedance can be more reliably resolved during the inversion and it can better predict the horizontal properties of reservoirlayers. As a result, it has been widely applied in coalfield exploration. In this study, wetarget at recognizing rock properties of a coal layer in Jilin Province using wave impedanceinversion. The results showed that in the wave impedance section the strata contactrelationships are better resolved for different geological units, especially the unconformity.Compared to the conventional seismic time section, the wave impedance section can betterrecognize coal layers and is more reliable in reservoir prediction. Through this study, wepredict a new coalfield reserve in Jiutai-guandi area, which is also proved by drillings.For the Longjiabao coalfield, we analyzed the relationship between seismic phasesand deposit phases. By combining seismic inversion results, dynamic features such asinstantaneous parameters of seismic reflection waves, drilling results, local geology andprevious coal prediction results, we comprehensively predicted coal reserves ofsoutheastern margin of Songliao Basin.