Shallow 3D seismic-reflection imaging of fracture zones in crystalline rock
Shallow 3D seismic-reflection imaging of fracture zones in crystalline rock
复制标题
结晶岩石断裂带的浅层 3D 地震反射成像
DOI：
--
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
C. Juhlin
中科院分区：
文献类型：
--
作者：
C. Schmelzbach;H. Horstmeyer;C. Juhlin
一个有限的三维地震反射数据集被用来绘制结晶岩石的裂缝带，用于核废料处理场地的研究。地震反射数据同时记录在两条大致垂直的剖面上（1850米和1060米长），并以400 x 400米的接收器阵列为中心，在两条线的交叉处采样了680 x 960米(2)的三维区域。高水平的源产生的噪声需要一个处理序列，包括表面一致的反褶积，这有效地增加了反射信号的强度，以及一个线性tau-p滤波方案，以抑制任何剩余的直接sv波能量。柔性分束方案显著平衡和增加了CMP褶皱，但偏移量和方位角分布仍然不规则；宽的方位角范围和800米的偏移量只在场地的边缘发现。三维倾角移动和三维叠后偏移是成像具有冲突倾角约40度的事件所必需的。尽管不规则的采集几何形状和高水平的源产生的噪声，我们获得了丰富的结构细节图像。在最后的数据量中，追踪了7个连续到半连续的反射事件，最大深度约为750米。以前的二维地震反射研究和钻孔数据表明，裂缝带最有可能是反射的原因。
A limited 3D seismic-reflection data set was used to map fracture zones in crystalline rock for a nuclear waste disposal site study. Seismic-reflection data simultaneously recorded along two roughly perpendicular profiles (1850 and 1060 m long) and with a 400 x 400-m receiver array centered at the intersection of the lines sampled a 680 x 960-m(2) area in three dimensions. High levels of source-generated noise required a processing sequence involving surface-consistent deconvolution, which effectively increased the strength of reflected signals, and a linear tau-p filtering scheme to suppress any remaining direct SV-wave energy. A flexible-binning scheme significantly balanced and increased the CMP fold, but the offset and azimuth distributions remain irregular; a wide azimuth range and offsets 800 m) are only found at the edges of the site. Three-dimensional dip moveout and 3D poststack migration were necessary to image events with conflicting dips up to about 40 degrees. Despite the irregular acquisition geometry and the high level of source-generated noise, we obtained images rich in structural detail. Seven continuous to semicontinuous reflection events were traced through the final data volume to a maximum depth of around 750 m. Previous 2D seismic-reflection studies and borehole data indicate that fracture zones are the most likely cause of the reflections.