改进的相对折射静校正方法

An improved relative refraction statics technique

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

常规折射静校正方法, 诸如延迟时法、互换法等, 需要拾取准确的初至和追踪同一高速折射层, 这在复杂地区比较困难。因此, 人们提出了相对折射静校正方法, 但是当地震资料信噪比低, 折射波初至能量变化大时, 效果不很理想。为此, 提出一种改进的相对折射静校正技术 (IRRS), 它基于折射波相邻道的相关特征, 用相关系数和双时窗求取每相邻道的相对时移, 进而用统计优化方法确定每一桩号上相邻道的唯一相对时移。

Conventional refraction statics techniques such as delay time method and reciprocal method suffer from pickup of accurate first break of refraction waves and tracing of a common high velocity refractor which are hard to obtain in complex area. To cope with these problems, relative refraction statics method was developed. However conventional relative refraction statics methods fail to yield desired results when S/N ratio is low and the energy of first break changes rapidly. This paper presents an improved relative refraction statics (IRRS) technique. Based on the correlation characteristics of refracted waves on adjacent traces, the method calculates the relative time shift between adjacent traces by correlation coefficient method and double time windows, and estimates an unique relative time shift for each stake on statistic optimization basis. Tests on synthetic and real data show that the method is of high precision, applicability, and automation. The method can yield the static quantity of short and long wavelength.