折射模型约束的初至波走时层析方法  

Tomography method constrained by refraction model for traveltime of first arrival wave

作　　者：马青坡 李培明 吕景峰 何永清 冯发全 赵薇薇 MA Qingpo;LI Peiming;LYU Jingfeng;HE Yongqing;FENG Faquan;ZHAO Weiwei(Acquisition Technology Institute,BGP Inc.,CNPC,Zhuozhou,Hebei 072751,China;BGP Inc.,CNPC,Zhuozhou,Hebei 072751,China;Tarim Geophysical Division,BGP Inc.,CNPC,Korla,Xinjiang 841000,China)

机构地区：[1]东方地球物理公司采集技术中心,河北涿州072751 [2]东方地球物理公司,河北涿州072751 [3]东方地球物理公司塔里木物探处,新疆库尔勒841000

出　　处：《石油地球物理勘探》2025年第1期92-99,共8页Oil Geophysical Prospecting

基　　金：中国石油天然气集团有限公司科技项目“物探核心装备与软件研制”之课题“地震采集工程软件系统KLSeis Ⅲ研发”(2021DJ3604)资助。

摘　　要：折射和初至波走时层析是两种主要的近地表建模和静校正方法,广泛应用于地震数据处理。折射技术在折射层相对稳定的地区应用效果较好,但提供的模型是层状模型,无法直接应用到叠前深度偏移。初至波走时层析可以较好地反映近地表结构的纵、横向变化趋势,但受限于实际数据采样不足、地形剧烈起伏等诸多因素,存在反演模型精度不高、局部模型不合理等问题。为此,提出了折射模型约束的初至波走时层析方法。首先,利用折射法计算延迟时和折射速度,结合表层调查、初至、近地表结构等多种信息建立一个符合地质意义的折射模型;然后,结合实际表层速度纵、横向变化规律,按照垂直时间等效原则将该折射模型离散化,用于约束层析建立最终的近地表速度模型。理论模型计算结果验证了该方法的有效性,实际数据处理结果证明了该方法反演的近地表速度模型更合理,应用效果好于无约束层析结果。Refraction and the first arrival wave traveltime tomography are two mainly used methods for near-surface model building and static correction.Refraction is appropriate to be applied in the area where the refraction layer is relatively stable,but cannot be directly applied to the case of prestack depth migration because the provided model is a layered one.The first arrival wave traveltime tomography can demonstrate the vertical and horizontal variation trends of the near-surface relatively well.However,due to factors such as insufficient actual data sampling and dramatically rugged topography,there exist problems of low accuracy and local illogicality of the inversion model.Therefore,this paper proposes a first arrival wave traveltime tomography method with refraction model constraint.As for the specific practice of the method,firstly the delay time and refraction velocity are calculated by the refraction method,and a geological refraction model is established based on information such as surface survey,first arrival,and near-surface structure.Then the refraction model is discretized in the principle of vertical traveltime equivalence,according to the vertical and horizontal variation rules of the actual surface velocity.Lastly,constrained tomography is applied to obtain the final near-surface velocity model.The theoretical model verifies the effectiveness of the proposed method.The actual data shows that the near-surface velocity model inverted by the proposed method is more reasonable and the application effect is better than that of the unconstrained tomography.

关 键 词：静校正 折射模型 走时 约束层析 多信息 

分 类 号：P631[天文地球—地质矿产勘探]