中文摘要：

随着世界经济对油气资源需求的日益增加，非常规海相碳酸盐岩油气藏的勘探开发逐渐被提上研究日程.为了对碳酸盐岩探区实现准确的叠前深度偏移成像，必须研究与之对应的速度分析方法.本文提出的成像角道集层析反演方法，利用波动方程双平方根算子叠前深度偏移提取的角道集作为速度分析道集，能够更为准确地反映速度和深度的耦合关系，并且减少了成像假象干扰，使得反演结果精度更高.模型和实际资料试算表明，该方法反演得到的深度域层速度场的速度较为准确，并且得到了质量较好的叠前偏移结果，能够较好地解决海相碳酸盐岩探区的速度分析问题.

英文摘要：

With the increasing demand of oil and gas resources caused by world economic development, the exploration and development of unconventional marine carbonate reservoir turn to hot research topics. The main seismic-geologic problems in marine carbonate exploration areas are rugged near surface, complex steep subsurface structure, deep target reflective layers, complex reservoir and so on, which make the conventional processing methods under the assumption of horizontal layered medium applied in clastic rock areas helpless. Prestack depth migration is an effective technique to improve the seismic data quality and image precision of complex structure in marine carbonate areas. In order to realize the accurate prestack depth migration in carbonate areas, the corresponding velocity analysis method must be researched first. This paper has proposed a tomography velocity analysis method based on image gathers, which use the angle domain common imaging gathers （ADCIGs） by prestack depth migration with wave equation double square root operator as the gathers of velocity analysis, and get the traveltime residual from depth residual by automatic fitting method. On one hand, ADCIGs can reflect the coupling relation of velocity and depth accurately and nearly have no artifact, making high precision of traveltime residual. On the other hand, the complex reflection can decompose into upward and downward transmission fortunately in the corresponding ray tracing method, which may simplify forward problem and increase the efficiency and accuracy of sensitivity matrix calculation, leading to higher precision result in velocity analysis. Examples of the synthetic seismic-geologic dataset and real dataset in marine carbonate areas show that the velocity field inverted by this method has accurate velocity value and interface depth, generating a high quality result of prestack depth migration. So this method can solve the velocity problem of marine carbonate exploration areas, however, low S/N prestack seismic data can impact the pre