高陡构造区二维地震测线观测方位探讨

Discussion on observation orientation of 2D seismic line in high-steep structural area

根据地震勘探理论,二维地震勘探的部署方案原则上要求主测线垂直构造走向,以期更好地反映构造形态;联络测线一般平行于构造走向,与主测线组成网格,能够在两个方向控制构造形态。通过对河套盆地高陡构造区的实际地震资料及相关文献资料的研究发现,二维地震测线的不同观测方位的地震资料对地质体刻画存在较大的差异。垂直构造的测线表层调查资料表现为近地表结构存在突变现象,在实际叠加剖面上因为高陡构造的屏蔽效应和散射效应导致地震资料品质明显降低。研究认为,高陡构造区的地震测线不一定严格按照垂直构造走向部署,需要在参考近地表资料及地震地质条件的基础上进行全面的综合考虑。

According to the theory of seismic exploration, the deployment plan of 2 D seismic exploration in principle requires the in-lines to be perpendicular to the structure strike to better reflect the structural feature. And the crosslines are generally parallel to the structure strike, which could form grids with the in-lines, so as to control the structural feature in two directions. Through the study of the actual seismic data and related literatures and papers on the high-steep structure area of the Hetao Basin, it is found that there are great differences in the description of geological bodies by using the seismic data of different observation orientations of 2 D seismic lines. The surface survey data of the lines perpendicular to the structures show abrupt changes in the near-surface structures. On the actual stacked profiles, the shielding effect and scattering effect of high-steep structures lead to the decrease of seismic data quality. According to this study, the seismic lines in highsteep structural areas are not necessarily arranged in strict accordance with structure strike. Instead, the deployment should be comprehensively considered on the basis of the near-surface data and seismic geological conditions.