共反射面元走时曲面计算方法

共反射面元走时曲面计算是共反射面元叠加的关键.常规共反射面元叠加必须通过相干搜索和优化确定共反射面元叠加公式中的三个属性参数（二维），从而确定共反射面元走时曲面，该类算法具有三点不足：①相干搜索及优化法计算量大；②共反射面元叠加公式仅适用小炮检距；③波前曲率半径取负号且较小时，共反射面元叠加公式基本不适用.为此，本文提出了利用共反射点射线追踪拟合共反射面元走时曲面的计算方法.模型计算证明该方法比传统共反射面元叠加走时曲面计算精度高,适用性强.

Calculation of travel-time curved face of common reflection surface

Calculation of travel-time curved face of CRS is crucial to CRS stack.First,three attribute parameters in stacking formula of CRS must be determined by coherent researching and optimizing in traditional CRS stack to ascertain travel-time curved face of common reflection surface.But this method has three shortages.Firstly,the calculated amount of coherence researching and optimizing is enormous.Secondly,the stack formula just fit for small distance between shot and receiver.Finally,stack formula is not applicable when curvature radius of wave-front is negative and low.In this paper,one calculation method using ray tracing of CMP to fit travel-time curved face of CRS is put forward.Application of the method on model calculation shows an excellent performance of the algorithm both in accuracy and applicability compared to traditional CRS stack travel-time of curved face.