What counts as exploration ventures in Challenge log?

I started today with 4 done.

Been gone a few days, Did a few quick exploration Ventures, through out today, finished off my 10 for the 1st group.

But for the 2nd part of the challange log I only have 4 completed?

Well if I do some math I'm not sure how to get to 15..

7 days x 24 hours/ 18 hours for field exploration = 9.3333...

So how is it that we can get to 15 exploration ventures of quick exploration don't count?
Do we need to do hunts? If so it should be renamed in log.