Iran is preparing to start up phases 12, 15 and 16 of its offshore South Pars gas field development over the next 12 months after more than eight years of development, the country’s oil minister said.

Iran has spent more than $3bn on the three phases, which are expected to come onstream in the current calendar year that began on 21 March, Rostam Qasemi said, according to Trend News Agency.

Market sources indicated that phases 15 and 16 could come onstream during the second quarter of 2013, with phase 12 starting up in the first quarter of 2014.

Iran shares South Pars – considered the world’s largest gas field – with Qatar, where it is called the North Field. State-owned Pars Oil & Gas Company (POGC) is developing the field through over 20 phases.

Phases 15 and 16 have a planned capacity of 50 million cubic metres a day (cm/d) of sales gas and 1 million tonnes a year (t/y) of liquefied petroleum gas (LPG) as well as condensate, ethane and sulphur.

Iran, which has the second largest proven gas reserves in the world after Russia, has been developing the South Pars field since the late 1990s. US-based sanctions against the Iranian economy have recently impacted partnerships with international companies on some of the phases.