The extent of opec 's spare capacity is uncertain .

欧佩克闲置产能到底有多少还不确定。

Iran holds opec 's rotating presidency .

伊朗目前是欧佩克的轮值主席国。

But oil could be heading beyond opec 's comfort zone .

但原油价格很可能冲破欧佩克的满意区间。

Iraq has been outside opec 's quota system for 21 years .

伊拉克21年来一直游离在欧佩克配额系统之外。

Opec supplies about 40 % of global oil demand .

世界约40%的石油需求是由欧佩克满足的。