You can take this sucker in 100 different directions.
Currently the combo needs 7UUR to happen. I'd be generous on the artifact mana, Thran Dynamos or maybe Gilded Lotus. The correct kind of artifact mana can also help you quickly recover from an Upheaval (Diamonds, or Moxen if you have them).
For control, red has Starstorm, Faultline, Earthquake, and more. Blue has Capsize, Mind Games, Evacuation, Propaganda, etc.
If you decide to fill their hand with extra cards (to make Blood Oath effective in non-Upheaval situations) blue has access to plenty - Prosperity, Arcane Denial, Indentured Djinn, Trade Secrets, and more. That sub-route also opens up possibilities with Black Vise like effects, and Mind's Eye.
2 specific cards I think I'd definitely include are Sudden Impact and Mystical Tutor.
Also, Sunder works with Blood Oath as well and in many ways is better than Upheaval. It too is an Instant, and its 1 mana cheaper. Plus if you are running artifact mana you can recover much faster.