How to change persistence layer at runtime in C#

I am embarking on a new project and I need some guidance from veteran architects/design pattern gurus!

My new project needs to have a number of persistence layers whereby the client can decide at runtime where the data will be stored, for example, in house SQL database, MS Exchange or Google storage.

The functionality will essentially be the same just the storage/implementation of each will be different.

I am not looking for a here is how you do it just a pointer to the best patterns to use to serve my purpose whilst still providing flexibility down the road as their will be CHANGE. I am trying to avoid concrete implementations that will inevitably lead to some nasty code smells.

I know it will involve some kind of DI along the way but anything pointers here would be greatly appreciated.