At the time of writing (after the RR-SRH match on 29/4), when 28 of the 56 league matches were over the points table was:

Now we look at the final points table for 2015, 2016 and 2017:
2015:

2016:

2017:

The main concern now is to predict who will be in the last four. We see that in the three seasons a team needed 16 points to qualify. This would correspond to 8 wins, or 7 wins and two no-results. Once you are in the last four it is even more of a lottery than in “normal” tournaments such as the World Cup.
A quick look at the half-time table for 2018 shows that the leader SRH has played 8 matches and have 12 points. To just scrape through they need just 2 wins in 6 matches.
Second-placed CSK have 7 matches and 10 points. They need 3 wins in 7 matches.
At the bottom end, DD have 7 matches and 4 points. They need 6 wins from 7 matches. But if you look at the history of the IPL, probably comebacks like this have happened on rare occasions.
Next to the bottom there is RCB with 6 matches and 4 points. They need 6 wins from 8 matches.