At this point, you have an estimate of the number of log-cycles of data that lie after the end of well-bore storage effects. The amount of 'analysable' data determines how sophisticated an analysis you can perform.
A good rule-of-thumb is that it takes at least 1/2 of a log-cycle
to develop characteristic shapes on a derivative plot that are
due to the effect of reservoir heterogeneity's or well-bore geometry.
If you have a mass of sharp spikes or valleys in the derivative,
then you are probably NOT looking at anything that represents
the reservoir properties.
Q: Is there more than 1/2 a log-cycle of data after the end of well-bore storage effects?
A1: No, the end of well-bore storage is at the last data point...
A2: No, there is only 1/2 of a log-cycle or less...
A3: Yes, there is lots of data after the end of well-bore storage!
A4: I don't know. I forgot to note the number of log-cycles...