Blizzard games include Starcraft2 can be very easily copied from drive to drive. Just drag and drop and copy the the stuff.
The more important question is do you know, as in the full path name of the source directory, for starcraft2 where is actually located. AND do you know what i the full path for where you will put it, for example:
"D:\Program Files\StarCraft II"
If you know that then is just a piece of cake drag-and-drop. What you will need to do is go to the blizzard/battle.net app starter thingy and go to its settings, and inform it of the new full path of where you relocated starcraft2. If you just want to be lazy, then you can just uninstall the blizzard/battle.net app and reinstall it and have it scan for your games again.