【作者】 孙辉；

【导师】 孙建国；

【作者基本信息】 吉林大学 ， 地球探测与信息技术， 2017， 博士

【摘要】 Kirchhoff型波束偏移隶属于束偏移成像方法,该方法将地震数据在各个窗中心分解为不同方向的平面波,并对所有平面波进行单独成像,可以处理复杂介质中经常出现的多至走时问题,是一种兼顾成像精度与计算效率的偏移算法。但这一方法使用的射线束传播算子随着传播距离的增加波束宽度发散过快,从而影响了相关属性信息的计算精度,并有可能降低最终的偏移成像效果。针对上述问题,文中在Kirchhoff型波束偏移中引入了可控制束宽发散的射线束传播算子,提出了Kirchhoff型动态聚焦波束偏移,取得了下列研究成果:(1)将动态聚焦射线束引入到Kirchhoff型波束偏移中,在射线追踪过程中采用变化而非固定的过度参数,使得中心射线上每一点均对应束腰位置,以此来控制偏移成像方法中的射线束传播范围,解决原有射线束宽度随传播距离增加发散过快的问题。(2)给出了以虚走时为基础的权函数计算方法以保证Kirchhoff型动态聚焦波束偏移的成像效果。(3)通过考虑纵向高度差对局部平面波分解步骤中时移项的影响,削弱起伏地形对偏移方法的影响,将Kirchhoff型动态聚焦波束偏移扩展成为了复杂地表条件下的成像方法。(4)通过考虑各向异性介质中的动态聚焦射线束,将Kirchhoff型动态聚焦波束偏移扩展成为了可以适应各向异性介质的偏移成像方法。多个数值模型以及实际地震资料被用于验证这一偏移方法,测试结果表明:Kirchhoff型动态聚焦波束偏移具有较强的成像能力,当这一方法被扩展到复杂地表以及各向异性介质中时仍然可以取得良好的成像效果。更多还原

【Abstract】 Kirchhoff beam migration is one kind of beam migration methods.In this algorithm,reflection data is divided into different beams,and each beam will be migrated to achieve the final result.Kirchhoff beam migration can calculate muti-arrival traveltime,which has the advantages of high precision and high efficiency.However,as the ray propagating,the beam width increases too fast,and it might reduce the calculation precision of grid nodes’ attribute information.To solve the difficult problem,the regular beam operator is replaced in Kirchhoff beam migration in this paper,we propose the Kirchhoff dynamic focused beam migration.The following achievements have been gotten.(1)Dynamic focused beam propagate operator has been applied in Kirchhoff beam migration to control the beam width.(2)A new method of computing the weight function is given to ensure the final imaging quality.(3)Kirchhoff dynamic focused beam migration is changed to adapt to the rugged topography.(4)Kirchhoff dynamic focused beam migration is also changed to adapt to the seismic data obtained from the anisotropic media.Several seismic numeral models and actual seismic data are adopted to verify the imaging capability of Kirchhoff dynamic focused beam migration.It shows that the new method has a strong imaging capability,even when it is adopted for seismic data under the rugged topography condition or anisotropic media,it also can obtain imaging results.更多还原