中文摘要：

折射波时延法假设折射层速度横向变化不大和折射面起伏不大,且同时求取炮点和接收点的延迟时间,存在＂此消彼长＂的问题。针对这些问题,提出了折射波相对时延法。利用共炮点道集相邻接收点的折射波时差和共接收点道集相邻炮点的折射波时差,实现了炮点相对延时和接收点相对延时的独立求取,并利用已知控制点上的绝对延时或基准面静校正值,结合基点网平差方法,把相对延时转成绝对延时或基准面静校正量。同时,通过对相邻两道记录进行互相关确定相邻道的折射波时差,避免了低信噪比地震资料连续追踪同一折射层来拾取初至时间的困难。对理论模型合成数据和实际资料的测试表明,相对时延法克服了常用时延法的不足,对折射层速度变化和折射面起伏有较强的适应性。

英文摘要：

Assuming that the lateral change of refractor velocity is small and the top surface of refractor is not highly rolling,refraction delay-time method estimates simultaneously source and receiver delaytimes using traveltimes.There is trade-off between the source and receiver delay-times calculated by the delay-time method.In order to eliminate problems in delay-time method,we propose a relative delaytime method for inversion of refraction traveltimes.The delay-time differences between adjacent receivers are estimated using only the traveltime differences between adjacent receivers in the common shot gather.Independently,the delay-time differences between adjacent sources are estimated using only the traveltime differences between adjacent sources in the common receiver gather.Based on the delay-times or datum statics known at some stations the delay-times at all sources and receivers can be obtained.Thus,the any trade-off between the source and receiver delay-times can be removed.Moreover,the traveltime differences between adjacent traces are determined by their correlations,which avoid to trace the same refractor in order to pick the first arrivals from seismic data with low signal-to-noise.Test results of synthetic and real data show that relative delay-time method can overcome the problems that common delay-time method suffers,and has strong adaptability for the highly varying refractor velocity and rolling refactor surface.