By the committee's 4-quadrant system, OU has 6 top tier (quadrant 1) wins: KU, Texas Tech, @Wichita State, TCU home and away, and USC neutral. Oregon is quadrant 2 even if you call it a road game.
The one critical game left is Iowa State. OU has no bad losses (quadrants 3 and 4), but losing to Iowa State at home would be by far the worst of the season. Win that one and there's no way OU misses the tournament. Lose out and it's anybody's guess.