Time pull-up and delay

The migrated images show considerable time delay in the vicinity of the injector, especially near the S2 zone at the base of the P formation. These time delays are likely to be caused by a velocity decrease in the reservoir due to heating and replacement of pore fluid with steam. Additionally, some evidence exists for time pull-up (reflection events which arrive at smaller traveltimes due to velocity increase) to the west of the injector. I will later discuss how these time pull-ups may be caused by velocity increases associated with a pressure front that has propagated to the west.