The Jiangying-based yard has been trying to get into the sector for the past two years, although yard officials decline to confirm the deal.
Sources say Evergas is paying $70m each for the newbuildings for delivery in the first half of 2017.
Some industry observers are puzzled as to why Evergas has turned to Yangzijiang as Chateauvieux-controlled Jaccar Holdings controls more than 23% of rival shipbuilder Sinopacific Shipbuilding Group.
