John T. Etgen (BP, Houston, Texas, USA)
PRACTICAL INSIGHTS AND TECHNIQUES IN SEISMIC VELOCITY ESTIMATION
2019 October 9th 3:00 PM (GMT +1)
The estimation of seismic wave speeds plays one of the most important and critical roles in seismic data processing. As we explore more complex and previously unexplorable provinces, as well as demanding ever-higher quality images from seismic reflection data everywhere, accurate velocity models are of paramount importance. I feel this topic is so important that everyone involved in creating images from seismic reflection data should understand the fundamentals of seismic velocity estimation and be able to recognize limitations and pitfalls in practical applications. This lecture is designed to provide insights into how seismic velocity estimation really works, what you can resolve, and what you will have difficulty resolving. I will present experiments that demonstrate the power and limitations of tomographic approaches that rely on iterative prestack migration. During this discussion you will learn concepts that might at first seem counter-intuitive; for example, lateral resolution of velocity anomalies can often be higher than vertical resolution. I will demonstrate simple and effective ways of performing analysis and quality control during velocity model construction. Finally, we will discuss emerging and advanced methods for building velocity models in the most complex settings that are currently of industrial interest.