Analysis, processing, and migration of the marine 4-component walkaway VSP data set from the SEG SEAM-1 Gulf of Mexico salt elastic modelling project: Synthetic study

The four component (4C) walkaway vertical seismic profile (WVSP) marine elastic synthetic data set from the SEG's SEAM-1 salt modeling project in the Gulf of Mexico (GOM) are examined, analyzed, processed, and migrated for P-P reflections using a reverse time prestack migration (RTM) algorithm to construct a subsurface image around the Well-1 VSP borehole. The imaging results from the three data sets; pressure-p, geophone vertical (z), and horizontal inline (x) components, have shown great successes in correctly locating and imaging sediments near and below the borehole as well as the vertical face of the salt, which is about 5 km away from the borehole. All major features of the salt body; from flat zones below the borehole to a vertical salt-face (with 90° dip), are imaged clearly by both the pressure (p) and the geophone z components. In the up-dip direction, the sediments are imaged nearly 3 km away from the borehole. Because of the differences in their frequency contents, the pressure-p and the geophone-z components are presented separately. Out of the three components (p, z, and x) the best image is obtained from the geophone vertical component due to its lesser noise content. Due to its sensitivity to horizontal motion, the horizontal geophone (x) seems to record a great amount of information from the waves traveling in more lateral or diagonal directions. A successful image of the salt face is also obtained with the x-component.