复杂断块地震资料裂步Fourier真振幅叠前深度偏移

Amplitude Preserving Prestack Split-Step Fourier Depth Migration for Complex Subsurface Structures

为了满足岩性油气藏、复杂断块等隐蔽油气藏勘探的迫切需求,需要获取高保真、高精度地震资料。由于传统的单程波方程叠前深度偏移只能反映波的运动学特征,并不能反映其动力学特征,因此不能保持真振幅特性。为此在裂步Fourier偏移中分别引入不同的真振幅校正算子,对传统的偏移算子进行补偿校正,并对成像条件进行改进。高保真裂步Fourier法叠前深度偏移具有较好的保幅特性,使振幅能够准确反映地下介质的反射系数序列,便于后续的更具地质意义的AVO-AVA分析、岩性解释等。实际工区应用结果表明该方法是一种稳定、快速、有效的叠前深度偏移方法,具有良好的应用潜力。

In the exploration of lithologic reservoir and subtle reservoir with complex structures,prestack depth migration is the fundamental process to obtain seismic imaging with high-fidelity and high-precision.The one-way wave equation used in traditional prestack depth migration describes the kinematic characteristics of the seismic wave,but cannot provide dynamic information.In order to preserve the amplitude,we propose to use various amplitude correction factors in the split-step Fourier migration to correct the migration operators with improved imaging condition.Prestack slip-step Fourier depth migration with high fidelity can preserve amplitude and thus accurately indicate the reflectivity series of the subsurface,which is essential for subsequent AVO/AVA analysis and lithologic interpretation.The migrated outputs for field seismic data reveal the complex structures accurately,indicating the amplitude preserving prestack splitstep Fourier depth migration to be the reliable,fast and stable algorithm for imaging complex geological structures.