Welcome to the forum, good_times.
Warp Well: This links the well with the
closest well on the
same floor. A Sim will dive into Well A, and come out at Well B, or whatever the nearest well is.
Uber Warp Well: This links the well to a specific well. The destination well must have a name, which can be set by Ctrl+Clicking the well, and choosing "Name Well" (or something similar).
Hope this helps.