应用波形拟合的炸药震源记录起跳点时间拾取方法  

First-arrival picking-up method of take-off point of explosive source record based on waveform fitting

作　　者：张一鸣 陈璐 袁燎 刘亿伟 肖光伟 纪国森 ZHANG Yiming;CHEN Lu;YUAN Liao;LIU Yiwei;XIAO Guangwei;JI Guosen(College of Marine Geosciences,Ocean University of China,Qingdao,Shandong 266100,China;Korla Branch,Geophysical Research Institute,BGP Inc.,CNPC,Korla,Xinjiang 841000,China)

机构地区：[1]中国海洋大学海洋地球科学学院,山东青岛266100 [2]东方地球物理公司研究院库尔勒分院,新疆库尔勒841000

出　　处：《石油地球物理勘探》2023年第2期315-324,共10页Oil Geophysical Prospecting

基　　金：中国石油天然气集团有限公司科学研究与技术开发项目“物探采集处理解释关键技术研究”之课题“非重复性时移地震处理解释关键技术研究”(2021DJ3703)资助。

摘　　要：初至拾取是地震数据处理中的关键步骤,其拾取的准确程度关系到浅表层速度模型建立的精度,并进一步影响后续叠加及偏移成像的效果。对于炸药震源激发形成的初至波,根据形成机制,其初至位置在地震记录中应由一个“向下的偏转”表示。而在实际地震数据初至拾取过程中,该“向下偏转的点”较难识别,而能够快速准确拾取的位置通常为波峰位置。基于理论模型,本文测试了拾取波峰及起跳点对速度模型反演的影响,证实基于炸药震源起跳点位置的反演精度高于基于拾取波峰位置。因而提出一种基于波形拟合的方法判断炸药震源的起跳点位置,即假定初至波可用李子波模拟,通过单道中对以波峰为中心的时窗内的样点值进行拟合,得到理论子波函数,以此方式快速、准确地搜索起跳点位置。通过理论子波模型,测试了波形拟合法的有效性及合理性;并应用该方法对塔里木T探区实际资料进行了试处理,表明该方法可准确拾取高信噪比地区炸药震源起跳点位置,同时具有一定的抗噪性,也能拾取较低信噪比地区炸药震源起跳点位置。First-arrival picking-up is a key step in seismic data processing.Its accuracy is related to the accuracy of the shallow surface velocity model and also influences the effects of stack imaging and migration imaging.According to the formation mechanism of the first arrival generated by explosive source excitation,its location should be represented by deflection at a take-off point in the seismic record.However,the take-off point is difficult to identify in the process of first-arrival picking-up during real seismic data processing.The position that can be picked up quickly and accurately is usually the peak.In this paper,the influence of picking up different positions(peak and take-off point)as the first arrival on velocity model inversion is tested by a theoretical model.It is proven that the accuracy of inversion based on the take-off point position of the explosive source is higher than that based on the peak position.Thus,this paper proposes a method based on waveform fitting to judge the take-off point.It is assumed that the first arrival can be simulated by the Lee wavelet.The theoretical wavelet function is achieved by fitting the values of sample points in the peak-centered time window in a single trace.This approach is used to fast and accurately search for the take-off point position.The validity and rationality of the waveform fitting method are tested by a theoretical wavelet model,and the method is applied to real data of the T exploration area in Tarim.The results show that the method can accurately pick up the take-off point position of the explosive source in an area with a high signal-to-noise ratio.It has certain noise resistance so that it can pick up the take-off point position of the explosive source in an area with a low signal-to-noise ratio.

关 键 词：初至拾取 波峰 起跳点 炸药震源 波形拟合 

分 类 号：P631[天文地球—地质矿产勘探]