This is a good question. My speculation may be incorrect, but the "velocity sag" is often seen beneath a gas sand. In the interbed multiple example we have a small anticlinal structure around 2.7 seconds. Gas in this structure increases the reflection amplitude and if you look closely you will see that the lead cycle has negative amplitude indicating we are going from high to low velocity. We have what seismic interpretors may refer to as a "bright spot." Reflection travel times through the relatively low velocity gas saturated interval are less than through the same interval filled with water. The added travel time through the gas saturated portion of the reservoir delays reflection arrival times from underlying layers. That delay is sometimes referred to as the "velocity sag." We don't see much data from beneath the interbed multiple sequence, but the underlying reflections around 3.4 seconds appear to drop or be delayed (sag) beneath the shallower gas sand. The usage is a bit colloquial but still common. see wiki.seg.org/wiki/Dictionary:Velocity_sag Something I need to do is discuss velocity anomalies in more detail. Thank you for your question!
![Noob To Max With DRAGON REWORK In Blox Fruits [FULL MOVIE]](http://i.ytimg.com/vi/LnBMOinoOvA/mqdefault.jpg)
Thanks for great video
Sorry Tom, But what does it mean by Velocity Sag?
Totally appreciate your effort
This is a good question. My speculation may be incorrect, but the "velocity sag" is often seen beneath a gas sand. In the interbed multiple example we have a small anticlinal structure around 2.7 seconds. Gas in this structure increases the reflection amplitude and if you look closely you will see that the lead cycle has negative amplitude indicating we are going from high to low velocity. We have what seismic interpretors may refer to as a "bright spot." Reflection travel times through the relatively low velocity gas saturated interval are less than through the same interval filled with water. The added travel time through the gas saturated portion of the reservoir delays reflection arrival times from underlying layers. That delay is sometimes referred to as the "velocity sag." We don't see much data from beneath the interbed multiple sequence, but the underlying reflections around 3.4 seconds appear to drop or be delayed (sag) beneath the shallower gas sand. The usage is a bit colloquial but still common. see wiki.seg.org/wiki/Dictionary:Velocity_sag Something I need to do is discuss velocity anomalies in more detail. Thank you for your question!