From the infocard of the research it's supposed to only work on your wells, but it just adds a +1 on the limit of all wells. I don't think it's a bad thing though, TEC loyalists depend heavily on being on their own turf, the second starbase in neutral or enemy wells kinda gives them the edge they lack when going for the enemy.

I think its a badly written info card. There are a lot of them at the moment. The Advent Rebel's protection of the unity (or something like that) doesn't tell you the effect only works in culture (at least thats what the effect internally says), and I don't think Return of the Fallen tells you that the resurrected ships appear at your home world. And I'm sure there are plenty more but I quit keeping track.

Considering planting just one SB in the enemy well and have it stay alive until it has its supply ability and sufficient armor already needs some serious Akkan action and luck I guess it pans out fine. Especially if you want to plant them on the right side of the well from the start (the side where the enemy reinforcements come from).