Faulting, High Resolution, Arkoma Basin
W.L. Chapman, G.L. Brown, D.W. Fair, 1983. "Faulting, High Resolution, Arkoma Basin", Seismic Expression of Structural Styles: A Picture and Work Atlas. Volume 1–The Layered Earth, Volume 2–Tectonics Of Extensional Provinces, & Volume 3–Tectonics Of Compressional Provinces, A. W. Bally
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Figure 1 is a migrated high-frequency seismic section from the Arkoma Basin, Oklahoma. Figure 2 is an interpreted version of Figure 1, with two objective zones marked by arrows. The first zone, a shallow gas sand, exists at depth A (1,067 m, 3,500 ft) and the second zone, a faulted horizon, is at depth B (2,438 m, 8,000 ft). Figure 3 is the same high-frequency seismic section before seismic migration. The high frequency content in both Figure 1 and 3 gives excellent vertical resolution. However, the lateral resolution in Figure 3 is quite poor as evidenced by faults that are not easily detected. In contrast, the faults are readily identified in Figure 1. The difference between Figure 1 and Figure 3 illustrates quite dramatically how lateral resolution of seismic data may be greatly improved by seismic migration. Furthermore, this generalization applies not only to structurally complex areas but also to areas with seemingly monotonous "layer-cake" stratigraphy.
Frequency content at reflection A objective (Figure 2) is approximately 100 Hz with sufficient bandwidth to uniquely map the limits of the producing sand. Further interpretive work with inter active modeling supported gas sand thickness estimates from seismic data. Frequency content at the deeper horizon B is about 80 Hz. The 20 Hz of high-frequency loss between A and B objectives is apparently due to attenuation in the thick, dominantly shale section between these two seismic markers. This shale section is approximately 1,371 m (4,500 ft) thick. When coupled with migration frequency content at the deeper zone is certainly sufficient to accurately map faults as shown in Figure 2. The fault on the right exhibits about 35 msec or 53 m (175 ft) of vertical displacement.