I have a Lenovo Ideapad Y500 and just wanted to ask what the partitions are for?

Apart from my C drive and another partition I've created, I have the following drives:

* D drive: "Lenovo" 25GB - (Only seems to be storing drivers at just over 2GB so can I safely shrink this?)
* 372MB Recovery Partition
* A 250MB EFI System partition
* 1000MB OEM partition
* 1000MB Recovery Partition
* 20GB Recovery partition (This one is confusing me the most)

It might be really basic or obvious but it just seems like a lot to have 7 partitions by default?