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Keywords:
Static correction High resolution Seismic reflection Reflection times
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An Improved Technique for Static Correction in a High Resolution Shallow Seismic Reflection Data using Difference in Reflection Times.
Abstract
Shallow Seismic reflection survey was carried out in Zaria, located in the basement complex of central northern Nigeria, with the aim of characterising the granitic batholith. However, the effect of near surface material, which could make reflection
events appear disjointed or deeper than they really are, could be enormous if not corrected for. This work sets out to correct for this events by making use of difference in reflection times estimated from initially known models of the subsurface. During the data acquisition the receivers where placed at 1 m interval, with a constant offset of 1 m. the common midpoint (CMP) method with a 12 fold coverage was employed. Previous refraction tomography model carried out in the area was used as a guide during the 2D velocity model generation, making use of the observed travel times. The observe time was used to generate the initial model, which was later corrected using the previous known subsurface model, thereby noting the difference in travel time induced by the near surface materials. The results obtained showed that the reflection events were more coherent and in their actual reflecting point on the statically corrected seismic sections, than the section without static correction because of the excess time from the near surface material with variable p wave velocity. This experiment has proved that difference in reflection travel times obtained from previous known model or borehole information in conjunction with the observed travel times serve as a better tool in applying static correction to seismic reflection data, than any previous known conventional methods that relies on a single technique.
Key Words: Static correction, High resolution, Seismic reflection, Reflection times
events appear disjointed or deeper than they really are, could be enormous if not corrected for. This work sets out to correct for this events by making use of difference in reflection times estimated from initially known models of the subsurface. During the data acquisition the receivers where placed at 1 m interval, with a constant offset of 1 m. the common midpoint (CMP) method with a 12 fold coverage was employed. Previous refraction tomography model carried out in the area was used as a guide during the 2D velocity model generation, making use of the observed travel times. The observe time was used to generate the initial model, which was later corrected using the previous known subsurface model, thereby noting the difference in travel time induced by the near surface materials. The results obtained showed that the reflection events were more coherent and in their actual reflecting point on the statically corrected seismic sections, than the section without static correction because of the excess time from the near surface material with variable p wave velocity. This experiment has proved that difference in reflection travel times obtained from previous known model or borehole information in conjunction with the observed travel times serve as a better tool in applying static correction to seismic reflection data, than any previous known conventional methods that relies on a single technique.
Key Words: Static correction, High resolution, Seismic reflection, Reflection times
