High-Density Seismic Acquisition Technology

With the 3-D seismic exploration widely used in coal mining areas, The 3-D seismic technology of acquisition, processing and interpretation has matured.It provided a large number useful information about the simple structure underground,the thickness and undulating forms of coal seam,the underground mined area etc.,it provides a scientific basis for coal production.After comparison of Exploration and Mining,what the data of seismic interpretation reveals about the faults drop of more than 10m,the collapse columns diameter of more than 30m,folds larger than 10m have a high degree of accuracy,the accuracy of the faults drop of less than 5m are low.But with the requirements of the mine exploration precision increase,the surface conditions turn to complex,the size of exploration targets decrease,exploration depth gradually increased from shallow to deep, The exploration target shift from structural exploration to lithological exploration.High-density 3-D seismic exploration technology emerged when the conventional seismic exploration has gradually can not meet the requirements of the task.Compared with a conventional 3-D seismic exploration,it have small spatial sampling interval,high covering,wide-azimuth and distributive offset,etc.It uses small size bin and received by single geophone can effectively improve the resolution,SNR and Fidelity.It also can improve precision of exploration to meet the increasingly requirements of high-precision seismic exploration.The thesis based on the analysis of the data quality and the acquisition methods of the conventional 3-D seismic exploration,it described the principle of High-density 3-D seismic acquisition technology through analyze the relationship among the time sampling rate and spatial sampling rate,the fold,the observation systems,geophone combination and high-resolution,high-SNR,high-fidelity.The thesis illustrates the advantages of the high-density 3-D seismic acquisition by analyze the motivating factor,receiving factor and compared the size of bins,fold,offset and azimuth distribution with conventional 3-D seismic survey.And using Tesseral-2D software to establish the geological model of Faults and collapse columns for forward simulation of different drop faults and different diameters collapse column.Through the above means,the thesis mainly studied the survey design optimization of the High-density 3-D seismic and the precision of structural exploration in High-density 3-D seismic acquisition.Finally,the thesis achieved the following results:single well without combination exploded and single geophone to receive help to improve the fidelity of seismic data.However,in low SNR regions may be appropriate to take the geophone combination to receive the signal to increase the SNR.In these regions should use a large amount of drugs to stimulate instead of the combined excitation.The offset and azimuth distribution of the high-density obeservation system is more uniform and higher covering can increase the stacking energy,suppress interference and improve SNR.The 2-D forward simulations of faults and collapse columns show that,high-density seismic acquisition using a small bin can detect the small faults and small collapse columns that conventional seismic exploration can't detect,more capable in describing the large size faults and collapse columns.Instance of a mining area in Changzhi,found that the location of small structures detected by high-density seismic method is more accurate and some small faults always neglected by conventional seismic exploration also can be detected by high-density seismic exploration.Draw by analysis that the detection of small structure in high-density seismic acquisition are more accurate.