摘要
复杂地表的静校正问题往往被归结为近地表层速度的求解问题,地表越复杂,近地表速度的求解就越困难。针对塔里木盆地沙漠地区地表条件异常复杂、原始资料信噪比低、静校正问题突出的特点,首先在表层结构分析的基础上进行静校正方法的研究,先后应用了初至折射静校正、沙丘曲线静校正和层析反演静校正法;根据沙丘内部地震波传播速度与沙丘厚度有关,提出了对沙丘曲线方法的改进,即根据v(hi)与实测值vi之间的偏差δi来计算(∑δ2i)^(1/2)和max|δi|,如果在事先给定的误差范围内,则认为拟合有效。实际中往往采用二次或三次多项式拟合来求取近地表速度。处理结果表明:用多项式拟合求取表层速度的静校正法在沙漠地区是切实可行的,为沙漠地区表层速度的求取提供了新的途径。
The issue of static correction on the complex ground surface comes down to the solution of near-surface layer velocity,so the more complex the ground surface,the more difficult the velocity of near-surface layer to be obtained. According to the peculiarities of ground surface in the desert area such as the abnormally complicated surface condition,low signal-to-noise ratio of source data,and other involved problems,based on the analysis of surface structure,we conducted a study on several static correction methods including the first arrival refraction wave statics,the dune curve statics,and the tomographic inversion statics. According to the relationship between the spread velocity of seismic wave inside the dune and the thickness of the dune,the dune curve statics was improved in this way that in actual calculation,either the quadratic or the cubic polynomial fitting was used for solving the surface velocity,and the mean square error (∑δ2i)^(1/2) and the max|δi|imum deviation were calculated by the deviation between V(hi) and the actual value of vi,and if the calculated results are within the given range of error,it shows that the fitting is effective. Results show that this static correction method by the polynomial fitting is practical and provides a new way for calculating the velocity of ground surface in the desert area.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2009年第6期37-39,共3页
Natural Gas Industry
关键词
塔里木盆地
沙漠地区
多项式拟合表层
速度
静校正
Tarim basin,desert area,polynomial fitting,surface layer,velocity,static correction
