三维地震勘探在构造复杂地区的应用

Applied Results of 3D Seismic Prospecting in Shallow Coal Seam Buried Areas

山西某勘探区地形较平坦,相对高差较小,地表多为第四系黄土覆盖,零星有基岩出露,岩石风化严重,无潜水位,激发条件较复杂。该区主要可采3#煤层埋藏最浅为75m,最深处245m,层位沉积不稳定,厚度变化剧烈;15#煤层上距3#煤层90m,±沉积相对稳定。该区二煤层形成的反射波T3和T15波虽可辨认,但因煤层埋深较浅,易受浅层干扰,有效叠加次数减少。通过实验,确定了激发及接收参数;在资料处理上利用叠前及叠后反褶积以提高分辨率;在解释中,充分利用水平切片、层拉平切片等方法,结合相干体、方差体技术进行相关特征对比及验证,有效识别出勘探区内的断层、陷落柱、采空区、无煤及薄煤区,为煤矿生产提供了可靠的地质保障。

An exploration area in Shanxi has relatively flat ground, smaller relative elevation, mostly covered by Quaternary loess, scattered bedrock outcropped and serious weathered, no phreatic water, thus quite complex shot conditions. No.3 coal seam shallowest buried depth is 75m, deepest 245m, unstable and drastic changed thickness; No.15 coal seam is above the No.3 coal seam with an interval of about 90m, relatively stable. The reflection waves T3 and T15 can be recognized, but because of coal seams are shallow buried thus easy to be interfered, effective stacking fold reduced. Through experiment, shot and receiving parameters are determined. Prestack and poststaek deconvolutions were used in data processing to improve resolution. During interpretation, made the best of time slices and layer flattened slices combined with coherence cube and variance cube techniques carried out correlative features contrasting and validating, effectively identified fault, subsided column, gob area, coal barren and thin coal areas in the exploration area, provided reliable geological guarantee for coalmine production.