Saudi Arabia's state oil company Aramco 2223.SE has signed contracts worth more than $25 billion for the second phase of the expansion of its Jafurah gas field and the third phase of expanding its main gas network, its CEO Amin Nasser said on Sunday.

Saudi Arabia is working on developing its unconventional gas reserves, which require advanced extraction methods such as those used in the shale gas industry.

Jafurah is the kingdom's largest unconventional non-oil associated gas field and is potentially the biggest shale gas development outside the United States, with reserves reaching 229 trillion cubic feet of gas and 75 billion barrels of condensates.

"By generating an anticipated 2 billion standard cubic feet per day of sales gas by 2030, this bold initiative will strengthen Saudi Arabia's position as one of the top national gas producers in the world", said Nasser, speaking of the Jafurah field at a contracts award ceremony in Dhahran.

The main gas network expansion will add 4,000 more kilometers of pipelines, boosting capacity by around 3.2 billion standard cubic feet per day and connecting several additional cities from across the country to the network, he said.

Companies awarded contracts for the expansion in Jafurah included a consortium involving Hyundai Engineering & Construction 000720.KS, while Chinese state energy giant Sinopec 600028.SS figured among the firms involved in the main gas network expansion.

Source: Reuters (Reporting by Jaidaa Taha, Adam Makary in Cairo and Federico Maccioni in Dubai; Editing by Timothy Heritage and David Holmes)