层析成像低速带速度反演和静校正方法

Tomography for LVZ velocity inversion and statics

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

在地形起伏剧烈和表层低速带速度横向变化较大的地区,做好野外静校正是取得高质量叠加剖面的重要一步,而确定表层低速带速度是做好静校正的关键。常规的 (基于折射波到达时或者微测井等)方法在复杂近地表条件下很难求得正确的低速带速度和静校正量。理论模型试验结果表明利用层析成像技术可由初至波的到达时反演表层低速带速度并求得静校正量。正演使用最短路径法射线追踪,反演采用SIRT方法。实际资料处理结果可看出明显改善了复杂地区 (沙漠、山地等)地震叠加剖面的质量.

Field statics is one of vital processing for achieving high quality stacked sections in areas with drastic topographic relief and sharp lateral variations of LVZ velocity. The determination of LVZ velocity is deemed the key to statics. Conventional methods that are on basis of refraction arrival time or microlog cannot yield proper LVZ velocity or static quantities in areas with complex near surface conditions. This paper presents an approach that derives LVZ velocity and static correction values from the arrival time of first break by using tomography technology. Shortest path ray tracing is used in the forward step and SIRT in the inversion step. Results from real data processing show that the approach can substantially improve the quality of seismic stack sections in areas with complex near surface conditions such as desert and mountainous region.