三维地震勘探在古交地区的应用

Application of 3D Seismic Prospecting in Gujiao Area

古交地区属山地地形,相对高差较大,黄土塬、梁、峁较为发育,表浅层地震地质条件很差。区内含煤地层为石炭二叠系地层,其中2#、8#煤层对应的反射波T2、T8波,全区可连续追踪对比。该区镇城底矿南四采区开展三维地震勘探的成功经验说明,在山区复杂条件下进行高分辨率三维地震勘探,一要重视激发条件(井深、岩性)和接收条件的改善,如基岩激发、检波器埋置等;二要尽量消除地震数据中与地质结构无关的时移、衰减等各种畸变影响,认真做好资料处理工作,如谱白化反褶积、浮动基准面校正、自动剩余静校正等工作,以提高信噪比和分辨率。该采区获得61.5%的Ⅰ类时间剖面证明在该类地区开展高分辨地震勘探具有可行性。

The Gujiao area is a mountainous region, relative height difference is rather large, loess tableland, ridge and hill landforms are rather well developed, surface and near-surface seismic-geologic conditions poor. Coal measures strata belong to the Permo-Carboniferous System, in which Nos.2 and 8 coal seams corresponding T2 and T8 reflection waves can be continuously traced in the whole region. The successful 3D seismic prospecting in the South No.4 winning district, Zhenchengdi coalmine have illustrated that high resolution 3D seismic prospecting in complex mountainous area need to ： the first is think much of to improve shot condition （hole depth, lithology） and receiving condition, such as shot in bedrock, geophone imbedding etc.; the second is to eliminate various distortions such as time-shifting, attenuation etc. irrelevant to geological structures in seismic data as far as possible, do the best of data processing, such as whitening deconvolution, relocatable datum correction, automatic residual statics etc. to improve S/ N ratio and resolution. The winning district obtained 61.5% Category I time sections demonstrated that to carry out high resolution seismic prospecting in such areas is feasible.