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    双重查表驱动的地震数据快速规则化方法

    Fast seismic data regularization using a dual lookup-table strategy

    • 摘要: 复杂地区地震勘探受山地、农田、居民区等特殊地貌限制,往往难以实现规则化采集。连片工区处理中,各区块观测系统参数的差异往往导致拼接区域难以无缝融合。不规则采样地震数据在处理中容易产生空间假频与采集脚印等假象,需通过五维规则化实现数据的均匀采样,提升后续建模、成像及解释的效果。现有的规则化方法主要通过反泄漏傅里叶变换(ALFT)计算不规则地震数据的频谱,再反变换得到预设坐标的地震数据。处理五维地震数据时,数据量的指数级增长使得非规则离散傅里叶变换(NDFT)计算复杂度急剧膨胀,且ALFT需要上百次迭代,导致五维规则化难以满足工业化生产应用的需求。因此,提出了双重查表驱动的地震数据快速规则化方法,一方面通过预计算傅里叶(Fourier)基函数表格降低NDFT的计算量,另一方面,以查表运算替代NDFT的多次迭代计算,仅需执行一次正、反变换即可获得与传统ALFT相当的结果,效率提高近百倍。此外,利用有效信号在f-k域沿径向线汇聚于原点的特性,可以有效压制假频干扰,显著提升稀疏采样条件下的规则化精度。目前该方法已经成功应用于两个工区,实际地震资料处理结果充分验证了方法的有效性与实用性。

       

      Abstract: Seismic exploration in complex areas is often constrained by challenging terrains such as mountains, farmlands, and residential areas, making regularized acquisition difficult. Furthermore, in merged-survey processing, discrepancies in acquisition geometries across different areas often hinder seamless data integration at the junction zones. Irregularly sampled seismic data tend to suffer from spatial aliasing and acquisition footprint artifacts during processing. Five-dimensional (5D) regularization is required to sample the data uniformly, thereby enhancing the quality of subsequent modeling, imaging, and interpretation. Existing regularization methods primarily employ the anti-leakage Fourier transform (ALFT) to compute the spectrum of irregularly sampled seismic data, followed by an inverse transform to reconstruct the data onto predefined coordinates. However, for 5D seismic data, the exponential increase in data volume leads to a sharp rise in the computational complexity of non-uniform discrete Fourier transform (NDFT) calculations. Combined with the hundreds of iterations required by ALFT, 5D regularization becomes computationally infeasible for industrial-scale production. Therefore, this study proposes a fast seismic data regularization method using a dual lookup-table strategy. By precomputing Fourier basis function lookup tables, the computational burden of NDFT is significantly reduced; meanwhile, replacing iterative NDFT calculations with table lookup operations requires only a single forward and inverse transform to achieve results comparable to those of conventional ALFT, improving computational efficiency by nearly 100 times. Additionally, by leveraging the property that effective signals converge to the origin along radial lines in the f-k domain, aliasing artifacts are effectively suppressed, significantly improving the regularization accuracy under sparse sampling conditions. Currently, this method has been successfully applied to multiple Sinopec surveys, and the processing results from field data have fully validated its effectiveness and practicality.

       

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