基于窄带技术与球面波插值的井间走时计算

Cross Well Travel Time Computation Based on Narrow BandTechnique and Spherical Wave Interpolation

井间层析成像方法以其高精度和高分辨率的特点在工程勘查和石油勘探开发中得到了广泛应用,地震波走时作为层析成像过程中的一个重要参数,它的计算精度往往决定了成像的准确性。本文针对井间地震的实际情况,采用窄带技术进行波前扩展、球面波插值技术进行局部插值相,二者相结合构建新算法来获取井间地震波的走时。通过模型实验的对比分析得出以下结论:(1)本文改进后的算法具有计算精度高的优点,从而适用于井间地震波走时计算;(2)针对井中激发点位于物性分界面的情况,算法能够稳定地计算走时并满足井间层析成像的要求;(3)算法在复杂模型下也能够正确计算走时并正确地反映井间地震波波前的传播情况。

Cross-well tomography has been widely used in engineering and petroleum exploration for its high precision and high resolution features.As an important parameter in seismic tomography,theoretical travel time calculation determines the accuracy of the imaging directly.In this paper,a new algorithm combining narrow-band technology for wavefront expansion and spherical wave interpolation technology for local interpolation is used to obtain the actual travel time of cross-well seismic waves.The comparative analysis of model experiments indicate that,firstly,This improved algorithm has the advantages of high accuracy for cross-well seismic travel time calculation.Secondly,for the case of excitation point located on the interface of physical properties,this algorithm can calculate travel time consistently,meeting the requirements of cross-well tomography.Thirdly,this improved algorithm can precisely reflect well seismic wave propagation in complicated models.