3D Seismic Survey Design: Coil Shooting, Multi-Component (3C) Receivers with Gulf of Mexico and Caribbean Case Histories
Kocel, Eray 1986-
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The effectiveness of seismic imaging depends on numerous factors, beginning with how the data are acquired. The analyses presented in this theses show the importance of survey design, as individual parameters exert a strong influence over the resulting subsurface illumination. Survey design studies discussed here with different geological settings and geographical locations include: 1) Marine surveys with circular shooting for a subsalt target in the Gulf of Mexico, 2) Multicomponent land seismic survey designs for an unconventional resource, and 3) Integrated geophysical data analyses and survey design for a blind fault imaging at the 2010 Haiti earthquake epicentral area. In the case of marine surveys, the dual-coil design provides full-azimuthal coverage, whereas the Wide-azimuth surveys (WAZ) contain some acquisition footprints due to their straight-line geometry with limited-azimuthal coverage. Survey design optimization quantified the WAZ survey as having 20 % less illumination intensity than the dual-coil survey. For the multicomponent survey design, we analyzed the effects of VP/VS values (2, 4, and 6), target depth (800, 1,600, and 3,200 m) and orthogonal or slanted shot geometries. The updip shifting of the illumination area due to target layer inclination (5˚, 15˚, and 30˚) required longer offsets to fully capture the seismic data. Staggered (periodically shifted) receiver lines achieved smaller bin sizes (6.25 m vs 25 m) with a very little additional acquisition effort. We also consider a case history from Léogâne fan-delta in Haiti, where some of the worst shaking was located by the 2010 Haiti earthquake. This intense shaking of the fan-delta area was attributed to either activation of a blind thrust fault, ~4 km beneath the surface, or to a strike-slip motion along a shallow, ground-breaking fault. We acquired seismic, gravity, and GPS data which were integrated with remote sensing studies. Our integrated results indicated disruptions of the near-surface material in the Léogâne region. Survey design studies suggested that multiple 2D seismic lines with 6 km offsets and optional marine surveys may be required to image the proposed blind fault. This thesis suggests novel seismic survey designs for a variety of subsurface geologies.