-snip-
But remember, the timelines of Half-Life 2 and the original Portal are somewhat simultaneous at the point where Combine forces take control of the Earth. Around this time, Chell awakes from stasis and this is where Portal takes place. After Chell is dragged back into the facility by the Party Escort Bot, Kleiner and Eli begin research on the teleportation system and test it with the cat. During the time between HL2 and HL2:EP2, Chell is in stasis and is being watched over by Rattman. Couple 1000s of years later, Portal 2 takes place. Half-Life 3 will take place possibly sometime after Eli is killed at White Forest, during time of Chell's stasis. Could be that HL3 will start shortly before Chell awakes for the first 50 days after being put into stasis.