The Impact of the Parameter Estimation Strategy in the CRS Method

The common-reflection surface (CRS) method is a powerful alternative to the traditional commonmidpoint (CMP) stacking, as it enables stacking using more traces than CMP. The CRS method is based on a traveltime that depends on three parameters in the 2D case, and in eight parameters in the 3D case. Traditionally, to keep computational costs low, these parameters are estimated based on a sequence of single-parameter searches, in which each parameter is estimated in turn, while keeping the others fixed. Alternatively, a global optimization method can be used to estimate all parameters simultaneously. In this paper, we analyze the impact of using such a global method. We show that the resulting image may be much improved. We also show that the parameters estimated using the traditional search may not be accurate, and may not result in a large coherence when used in the full CRS traveltime.