The all-rounder finished with four for 24 but an outstanding partnership between Michael Bracewell and Brad Wilson was also instrumental in Otago's fifth win in seven games.
The victory has seen the Volts (20 points) consolidate their place at the top of the domestic twenty20 standings.
Black Caps all-rounder Jimmy Neesham was a late inclusion in the squad but was left out of the starting XI. Earlier in the week he feared he may require surgery to correct a back complaint but has been given the all-clear.
He will be considered for selection for Otago's next match against Canterbury in Dunedin but only as a specialist batsman.
The Volts certainly have room for another top-order player despite posting a healthy 181 for eight.
Most of the runs were scored by two players. Bracewell and Wilson put on 96 for the third wicket and both bagged half centuries..
Bracewell's 50 came off 35 balls but he was out immediately after reaching the milestone for 53.
Wilson batted much deeper into the innings, scoring 67 from 46 deliveries to set up a decent total.
With the slog on, Otago lost some cheap wickets at the death and the team does have the look of a side which could benefit from another specialist batsman further up.
That said, the mix of the side meant Otago had plenty of bowling options and it was its sixth bowler who made the difference.
Wells has not been required much of late and Nathan McCullum's decision to throw him the ball proved inspired.
Wells started with a wide but that was soon forgotten with three of his next six deliveries all claiming wickets.
Wellington was well placed at 108 for four before Wells showed up.
Alecz Day perished first when he skied a catch which the bowler claimed despite the swirling breeze. The ball stayed in the air long enough for Matt Taylor to cross back on to strike.
He was hitting the ball superbly and was threatening to bat his side into a winning position.
But he also fell to Wells when he lofted a drive to McCullum in the covers. He had cracked four sixes in a fine knock of 65.
Jeetan Patel was next. He has often proved a tricky thorn to remove for Otago but holed out at long on.
Wells made it four when Luke Woodcock hit a return catch in his next over.
Dane Hutchinson and England's Jade Dernbach attempted to make it interesting with some healthy blows. But the home side was left needing 28 from the last over and got itself bowled out for 162.
