东营城区高精度三维地震采集方法研究

Study of High-Precision 3D Seismic Exploration Acquisition in Dongying City Area

根据东营城区内建筑物较多 ,环境干扰较大 ,地下构造复杂 ,断裂非常发育 ,目的层埋藏深 ,资料信噪比较低的特点 ,以地震老资料和钻井资料为基础 ,建立地震地质模型 ,利用射线追踪技术选取合适的观测系统参数。充分利用卫星数字地图 ,设计了灵活多变的观测系统 ,采用可控震源与炸药震源配合使用方法 ,及时对城区内地下面元的覆盖次数、方位角和炮检距的分布进行质量监控 ,利用现场处理系统对资料进行及时分析 ,提高了地震资料品质。所获得的东营城区高精度三维地震采集资料显示 ,其浅中层分辨率和中深层信噪比都有了明显改善 ,取得了良好的地质效果。

The target area is located in the central section of the Dongying center uplifted belt. The Dongying city area is about 80km 2 with many buildings and much ambient noise. Besides, the underground structure of this area is also very complicated, and the rupture in the mid-shallow layer is well developed owing to the Dongying center uplifted belt. Finally,the deep stratum lies very deeply, which makes the S/N ratio very low. Considering the surface and underground geological conditions, a geological model for this area was designed based on the past seismic data and drilling well data and suitable layout parameters were chosen by using the technology of ray tracing. At the same time, digital maps were used to help set the locations of shots and geophones, to monitor promptly the cover frequencies of underground bins, azimuth and offsets, ensuring the completeness of seismic data in the city area. During the course of data acquisition, strong ambient noise was avoided by way of controlling the burying condition of geophones and the quality of drilling wells. Moreover, utilization of an on-site processing system in data analysis also helped to improve the quality of seismic data. Owing to scientific design method and strict field construction, high precision 3D exploration was accomplished in 120km 2 of the Dongying city area, and it is shown that the resolution of mid-shallow layer data and the S/N ratio in mid-deep layer data have been greatly improved from the single shot records and stack profile.