Seismic Facies Analysis And Seam Thickness Prediction Of Middle Coalseam In Suntuan Mine

The thickness of coalseam tends to vary greatly due to changes in the sedimentary environment during the formation of coal,when mining,if the actual coal thickness is 10%-20%thinner than the designed,the coal output will drop by35%-40%,and studying the thickness of coalseam is also beneficial to prevent gas outburst.Therefore,studying the variation law of coalseam thickness and seismic prediction methods has important research significance and practical value for safe and efficient mining of coal mines.The thickness of the coalseam depends mainly on the relative balance between the space growth rate and the peat aggregation rate,only a relatively stable sedimentary environment is conducive to coalseam deposition,so the sedimentary environment?sedimentary facies?of the coalseam is the main factor for the change of coalseam thickness.Based on sedimentary facies analysis and logging facies analysis of coalseam,according to the difference in the characteristics of seismic parameters,divide seismic sequence,correspondence between seismic facies?seismic sequence?and sedimentary facies?stratigraphic sequence?,use seismic facies methods to divide different seismic facies,and different sedimentary facies of coalseam are given,delineate different sedimentary facies of coalseam.Due to changes in the thickness of the coalseam,it will cause changes in the attributes of the reflected wave of the coalseam,that is,cause changes of the reflected wave waveform,therefore,it is possible to predict the thickness of the coalseam based on changes in the reflection waveform of the coalseam.This paper systematically analyzed the data such as drilling and logging in Suntuan Mine,and use the relevant geological theory such as sedimentary facies and log facies,rely on the seismic facies analysis methods delineated the sedimentary facies of middle coal formation in the workarea,it is believed that there are mainly distributary channel and interdistributary bay two types of sedimentary facies in the workarea,and has discussed the control of sedimentary environment on coalseam thickness variation.A wedge-shaped seismic geological model which variation of coalseam thickness is established,simulated the response of seismic trace waveform varies with the thickness of the coalseam,the seismic facies division coalseam thickness prediction method based on waveform classification is studied.Applying this method to predicte coalseam thickness of 7₂ coalseam and 8₂ coalseam in the workarea of Suntuan Mine,processing actual seismic data under drilling constraints,the seismic facies method of waveform classification has higher precision in prediction of coalseam thickness than wave impedance inversion method and spectral moment inversion method,proved that waveform classification seismic facies method can predict coalseam thickness.