基于Chebyshev多项式的弯曲射线Kirchhoff叠前时间偏移

弯曲射线Kirchhoff叠前时间偏移被认为是一种综合了叠前时间偏移效率和叠前深度偏移精度的方法.本文以保精度地减少高阶Kirchhoff叠前时间偏移走时计算量为目标,在分析了Chebyshev正交多项式性质的基础上,建立了Chebyshev多项式约简系数表,进而用模拟退火法对转换系数进行分段优化,从而实现了在大炮检距...

Bend-ray Kirchhoff pre-stack time migration based on Chebyshev polynomial

Bend-ray Kirchhoff pre-stack time migration is considered as a kind of method which synthesizes the efficiency of pre-stack time migration and the precision of pre-stack depth migration. Aiming at decreasing the traveltime calculated amount of bend-ray Kirchhoff pre-stack time migration with preserving the accuracy, we particularly analyze the property of Chebyshev polynomial, and then make up the reduction coefficients graph with Chebyshev orthogonal polynomial, moreover, we take use of simulated annealing method to optimize the coefficient in terms of different intervals; thus, realize optimal approximation between optimized 2nd-order Chebyshev traveltime formula and high order one within the range of long offset. Finally, through the method verification of homogenous media, VTI media and field data, it is proved that compared with high order bend-ray migration, optimized 2nd-order Chebyshev migration presented in this paper not only decrease the traveltime calculation amount, but also acquire the comparative imaging accuracy with the high order one.