Study On The Influence Of Maximum Offset On The Interpretation Of Collapse Column

The development of the collapse column often causes serious damage to the coal seam and surrounding rocks,which causes great difficulties for coal mine production,including destroying the recoverable coal seam,reducing coal reserves,impeding mechanized coal mining,reducing mining efficiency,and increasing production costs.Moreover,the collapse column is also likely to cause large-scale roof collapse,water inrush and gas outburst,which seriously affects the safe production of coal mines.Seismic exploration is a very effective and common means of detecting collapse columns.There are numerous examples of coal mines successfully identifying traps.The identification of a certain size of collapse columns by 3D seismic exploration has become one of the main geological tasks of most coal mines in Shanxi.However,the accuracy of the collapsed column diameter explained by 3D seismic exploration still cannot meet the safety production requirements of coal mines.Coal mine safety production urgently requires a more accurate exploration range of collapse columns.Therefore,how to improve the accuracy of the collapse column exploration has been a problem that many scholars have explored and studied.In this paper,the formation mechanism and morphological characteristics of the collapse column and the response characteristics of the collapse column on seismic time profile and attribute slice are introduced in detail,which provides a reliable theoretical basis for the forward modeling of this paper.Then the paper starts from the parameter of the maximum offset in the observationsystem parameters.By setting different maximum offset parameters,the Tesseral-2D software is used to carry out forward modeling of different maximum offset parameters,and the different maximum offsets are obtained.The gun record is recorded,and then the vista processing software is used to process the seismic record.The processing steps include track header editing,first-pass cut,slap set,velocity analysis,motion correction,superposition,offset processing,and superposition and partialization obtained through these processes.The time profile is explained to explain the diameter of the collapse column,and the influence of the maximum offset on the interpretation of the collapse column is analyzed.The law of the influence of different maximum offsets on the interpretation of the collapse column is summarized from qualitative and quantitative aspects,and this interpretation is made.The reasons for the differences were analyzed in detail.This paper simulates the selection of the maximum offset from two aspects,and selects a reasonable design method for the maximum offset.Concluded as follow:(1)The simulation results show that the maximum offset within a certain range,with the increase of the maximum offset,the absolute error and relative error of the collapse column diameter and the actual collapse column diameter explained by the superimposed profile and the offset profile become larger.(2)According to the GX II software analysis,the main reason for the increase of the maximum offset is that the superimposed profile and the offset profile explain that the diameter of the collapsed column becomes larger: as the maximum offset increases,the ray will not be traced.The breakpoint on the left side,and the blind zone where the ray cannot be traced to the left side of the collapse column becomes larger.(3)The optimized design method of the selected offset is focused on the total energy reception while taking into account the receiving efficiency of each detector.The application of the simulation example shows good results.