Field Data Example

In this section, the proposed method is applied to the Friendswood cross-well data to extract super-virtual diffraction arrivals. This data set was collected at Exxon's test site located near Friendswood, Texas. The source and receiver intervals are both 3.05 m and the distance between the two wells is 182.9 m. There are 98 shot gathers with 96 traces each in this data set. Figure 4.8(a) shows a raw common shot gather and the target diffraction is outlined with 2 red lines. A zoom view of the diffraction is shown in Figure 4.8(b). In this example, the moveout of the diffraction is manually picked for the purpose of median filtering and Figure 4.8(c) shows the result after applying a median filter along the moveout curve. It is clear that the coherent noise is effectively removed by median filtering. To further improve the result, the super-virtual diffraction method is applied to the median-filtered events and the result is shown in Figure 4.8(d), which is of much higher SNR compared to Figure 4.8(c).