According to Reuters sources

Venezuela is a given at this point considering their predicament but Libya and Iran too means that they can at least work towards sealing an agreement on cutting production. But once again, this is the bare minimum expectations of markets right now - that a deal will be struck at the very least.

The question remains if they can convince Russia to pledge for deeper cuts. Reports are saying that Russia will only be willing to consider cuts of about 150k bpd, which means OPEC+ as a whole will be committing to just a 1 million bpd worth of cuts.