Data parallel wave equation datuming

Dimitri Bevc

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ABSTRACT

Seismic data gathered on land is distorted by irregular acquisition topography. Seismic imaging algorithms are generally applied to data which is redatumed to a planar surface. In regions of mild topography where the near surface velocity is much slower than the subsurface velocity, a static shift is adequate for the transformation. However, when the necessary shift increases in magnitude and when the near surface velocity is comparable to the subsurface velocity, the static approximation becomes inadequate. Under these circumstances, a static shift distorts the wave field and degrades the velocity analysis and imaging. In this case wave equation datuming is more appropriate than static shift.

Wave equation datuming is much more computationally intensive than static shift and is therefore seldom applied. Furthermore, redatuming may involve multiple applications of the datuming routine to estimate the near surface velocity structure. I implement a data parallel wave equation datuming algorithm which can be applied to land data as an alternative to static shift in order to improve velocity analysis and imaging and to estimate near surface velocity structure. The Kirchhoff algorithm is efficiently implemented on a Connection Machine CM5 and makes wave equation datuming practical.