The oasis is beside the Warick hotel not, opposite O'Connors pub?? (unless you've been drinking heavily of course)
O'Connors used to own a place almost behind the Hibernian building. It was a hotel and nightclub (possibly CJs).
As you walked (as I walked/stumbled) from the old cinema down to the prom, my recollection is The Oasis (with palm tree murals outside and ever so friendly bouncers) was on the right, as was the Warwick, this venue owned by one of the O'Connors was on the left. The Castle was durther down on the left and Setantas on the right down towards the prom.
This was 1988/1992, and I seem to remember that the Oasis looking derelict a few years ago so there is probably something different on the site now.