Let's put this into a stat calculator:
Ok, Kyogre's Max HP is 404.
Kyogres Lowest HP is 341.
Kyogre's Max Defense is 306.
Kyogre's Lowest Defense Possible is 195.
Groudon's Max Attack is 438.
Now, if Groudon uses Hyper Beam (or Earthquake) against Kyogre, how much damage will it do?
This is, for the benefit of the Groudon player, assuming max attack on Groudon (which isn't very likely).
Against the max stat, max HP Kyogre, between 155 and 182. Summary: 3HKO
Against the max stat, minimum HP Kyogre, between 155 and 182. Summary: 2-3HKO, depending on how much damage.
Against the lowest stat, max HP Kyogre, between 219 and 257. Summary: 2HKO
Against lowest stat, minimum HP Kyogre, between 219 and 257. Summary: 2HKO
So, if you have trained the perfect Groudon (meaning 31 Attack IV (good luck), 255 Attack EVs, and beneficial personality), the best you can hope for is a 2HKO, but if the Kyogre player has also done his research, you could be stuck with 3HKOs, and we know Groudon won't last that long.
So, to end this conversation, Groudon cannot OHKO Kyogre under any circumstances.