VERTICAL RESOLUTION OF A SEISMIC SURVEY IN STRATIGRAPHIC SEQUENCES LESS-THAN 100 M DEEP IN SOUTHEASTERN KANSAS

A 400-m long, 12-fold high-resolution common depth point (CDP) reflect ion seismic profile was acquired across shallow converging Pennsylvani an strata in the Independence area of southeastern Kansas. One of the principal objectives was to determine practical vertical resolution li mits in an excellent shallow seismic-data area with borehole control. The dominant frequency of the CDP stacked data is in excess of 150 Hz based on peak-to-peak measurements. Interference phenomena observed on stacked seismic data incorporated with models derived from log and dr ill-hole information suggest a practical vertical resolution limit of about 7 m, or one-third of the dominant wavelength. This practical res olution is slightly less than the predicted (theoretical) resolution l imit of 5 m based on the generally accepted one-quarter wavelength axi om. These data suggest conventional rules of thumb describing resoluti on potential are not accurate when reflectors on shallow, narrow bandw idth data converge rapidly across horizontal distances less than the F resnel Zone.