Estimating Static Shifts by Deconvolving Stacking Velocity Profiles
Turki Z. Al-Rowaili1*, Abdullatif Al-Shuhail2, Abdulaziz S. Al-Aslani1, and Gabor Korvin2
2KFUPM, Saudi Arabia
Seismic exploration aims to provide high-quality data in order to optimize finding hydrocarbon reserves and to minimize drilling costs. However, for land seismic data, near-surface irregularities act as a noise generator and create static problems, which can considerably degrade seismic images. We have investigated a potential and unconventional approach to extract static shifts from seismic data. This approach extracts time delays, generated by near-surface irregularities, from a stacking velocity profile for a given seismic reflector. This is accomplished by deconvolving the stacking velocity profile with the impulse response of the seismic acquisition spread. The impulse response is basically the stacking velocity profile due to the interaction between the acquisition spread and a single near-surface impulse time delay. We applied the method on a synthetic model that consisted of five horizontal layers and three near-surface irregularities. The lateral extents of the irregularities are equal to the full, half, and one-quarter of the spread length, which was 1,500 m. The time delays corresponding to the three near-surface irregularities were held constant at 8.0 millisecond. The stacking velocity profile from the third interface was hand-picked and showed high oscillations under the near-surface irregularities. This picked stacking velocity profile was deconvolved by the impulse response to estimate the time delays that caused the oscillations. The errors in the estimated time delays were consistently less than 10%, which demonstrates the ability of the proposed method to recover time delays from stacking velocity profiles.
AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain