Ireland join Australia and West Indies in Group B; Afghanistan, India and England in Group A.
Dubai: Ireland beat Afghanistan by five wickets to claim the ICC World Twenty20 qualifier final on Saturday.
The victory came just hours after the Irish qualified for their third consecutive World Twenty20 with a nine-wicket victory over Namibia.
Afghanistan had also already qualified after beating Namibia on Thursday in a preliminary final.
The final decided Ireland will play in the ICC World Twenty20 in Sri Lanka in September in Group B with Australia and West Indies. Afghanistan join England and India in Group A.
Led by a 77 off 57 balls from Mohammad Shahzad, Afghanistan set a challenging 152-7. But Ireland chased it down with seven balls to spare, led by Paul Stirling's 79 off 38 balls.
Ireland avenged losing to Afghanistan in the 2010 final.
"It's really pleasing to win a trophy. Ten games unbeaten is a fantastic effort from the lads," Porterfield said. "We're obviously looking forward to it, playing against Australia and the West Indies is going to be a tough task. We've got to keep working hard and improving our skills."
Afghan skipper Nawroz Mangal felt their total was sufficient.
"The batters achieved what we planned for, and getting the wicket of Porterfield on the first ball was a good start," Mangal said. "But the way Stirling played, he demolished every plan we had."
Earlier, Ireland denied Namibia its first trip to the World Twenty20. Ireland's bowlers again were the stars, restricting Namibia to 94 for 6 before their batsmen rattled up 96 for 1 in reply.
For Ireland, the wins add momentum to its bid to become a Test-playing side. Porterfield highlighted the fact it has appeared in not only every World T20 since 2009 but also the last two World Cups.
"From the last couple of World Cups, people have taken notice about the steps Irish cricket has been making," Porterfield said.
"It won't be easy in terms of making that step up (to test status) but we feel we are ready to do that. We are getting a pool of players together and we are getting even more depth in the squad. As long as we can keep that pool of players getting bigger and bigger, then we will compete at all levels. Hopefully, the ICC can give us the opportunity sooner rather than later."