伪谱法运算效率的提高及井间波场的正演模拟

伪谱法求解波动方程的常规算法,运算量大,运算时间长。笔者综合提高伪谱法计算精度和效率的方法,改进了常规计算流程里计算傅氏变换和反变换中需要多次使用计算的常量,把这些常量提到时间循环体外,从而避免很多重复运算,减少了运算次数,使运算效率提高了一倍以上,并结合目前隐蔽圈闭在油气勘探中的重要性,构建了隐蔽圈闭中一种特殊的构造,即透镜体模型,模拟了高速和低速透镜体模型中的井间波场特征,对比分析了2种模型的合成井间地震记录、时间切片及振幅特征,与理论分析的结果能够很好的相吻合。

THE EFFICIENCY IMPROVEMENT OF THE PSEUDO-SPECTRAL METHOD AND THE SIMULATION OF THE CROSS-WELL SEISMIC WAVE FIELD

In conventional pseudo-spectral method for solving the wave equation, the routine algorithm needs large quantities of computation and spends a long computing time. In this paper, the authors have integrated the pseudo-spectral method to raise the accuracy and efficiency, and improved its conventional algorithm of calculation constants which need multiple calculations in the Fourier transform and inverse transform in the procedure of calculation. These constants are brought out of the time loop structure, thus avoiding the duplication of many calculations and reducing the number of calculations. In this way, the computational efficiency has at least been doubled. Considering the importance of subtle traps in the oil and gas exploration, the authors have constructed a special structure for the subtle traps, namely the lens model. This algorithm was used to simulate cross-well field characteristics of high-velocity and low-velocity lens models and make a comparative analysis of synthetic cross-well seismic records, time slices and amplitude characteristics of the two models. The result is in good agreement with that of theoretical analysis.