Seismic Characterization of Hypogenic Karst Systems Associated with Deep Hydrothermal Fluids in the Middle-Lower Ordovician Yingshan Formation of the Shunnan Area, Tarim Basin, NW China

Figure 4

Seismic facies of epigenic karst systems and hypogenic karst systems of the Yingshan Formation in the study area. (a) Seismic attribute RMS (root mean square) map of the lower part of the Yingshan Formation. (b) Epigenic karst systems marked by the blue oval line across wells SN6 and SN5 seismic section, showing the typical individual string-beads-like seismic reflections. (c) Seismic attribute RMS (root mean square) map of the upper part of the Yingshan Formation. (d) Complex string-beads-like seismic reflections of hypogenic karst systems across well SN4 seismic section, developed associated with the faults. (e) and (f) Other seismic section showing complex string-beads-like seismic reflections of hypogenic karst systems, developed associated with the faults. The blue color indicates epigenic karst systems, distributed widely in the entire study area with the isolated punctate distributions; the green color indicates hypogenic karst systems, showing belt-shaped distributions along the SN4 fault zone.