AAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain
Practical Implementation of Wave-Equation Datuming for Resolving Near-Surface Problems
(1) Saudi Aramco, Dhahran, Saudi Arabia.
Complicated near surface geology and rugged topography can degrade the quality of the seismic images. Time shifts or statics are still the work horse for resolving near-surface related problems. These shifts are usually computed from simple near-surface velocity models. More recently, refraction tomography was used to build more sophisticated models. The limitation of statics is that they are based on vertical ray-path assumption. When this assumption is violated, as in areas of complex geology, this solution fails to resolve the distortions caused by the lateral velocity variations. Wave-equation datuming (WED) is a powerful tool to resolve near-surface related problems. It was introduced about thirty years ago but still is not a production tool yet, due to its need for accurate velocity models. Unlike conventional near-surface solutions, WED does not fail for complex near-surface models, such as those of refraction tomography.
In this paper, the evolution of conventional near-surface solutions is reviewed, and then those solutions are compared to WED. Also, we discuss how WED can practically be implemented in a production environment by showing a processing workflow, which can handle the data regularization and interpolation as well as velocity model building. This is demonstrated using a 2D seismic line acquired in an area with a challenging near surface geology.