(Adds comments, context) MOSCOW, Feb 20 (Reuters) - Consultations on a preliminary deal between leading oil producers to freeze output should be concluded by March 1 after a group led by Russia and Saudi Arabia reached a common position this week in Doha, Russia's energy minister said. In a television interview aired on Saturday, Alexander **vak also said that the agreement an**unced on Feb. 16 was weighty e**ugh. My point is that, in practice, this is e**ugh to agree," **vak told the Vesti on Saturday programme.