初至波走时信息在复杂地区近地表速度反演中的应用

Inversion of near-surface velocity through first-arrival traveltime in complex region

中国石化石油勘探开发研究院南京石油物探研究所,江苏南京210014

Institute of Geophysical Prospecting, SINOPEC Research Institute of Petroleum Exploration and Development, Nanjing 210014, China

在地表条件复杂的地区近地表速度横向变化十分剧烈, 对静校正及偏移成像的结果影响很大。要提高成像质量, 必须要有高精度的近地表速度。介绍了用初至波走时信息反演来确定复杂地区近地表速度的方法, 并用模型测试了方法的有效性, 最后分别用初至波走时信息反演法和常规方法建立了实测资料近地表速度结构, 并基于这 2种速度生成了叠加剖面。对比显示, 初至波走时信息反演法应用效果非常理想。

The near-surface transverse velocity varies dramatically in the complex region, affecting the quality of static correction and migration imaging seriously. High precision near-surface velocity becomes a key factor to enhance imaging quality. Inversion of near-surface velocity through first-arrival traveltime in complex region is briefly described. The effectiveness of the methods is tested on modeling data. Near-surface velocity models are built by the proposed method and conventional methods respectively on real data. Seismic stack sections based on these velocity models are produced, which reveals that the first-arrival traveltime inversion is ideal for building of near-surface velocity model.