While oil has been transformed during the past 30 years into a vibrantly traded global commodity, natural gas trading remains fragmented with prices in all regions but the US mirroring the oil price.

• 过去30年间，石油已发展成为一种交易活跃的全球性大宗商品，但天然气交易仍呈分散局面，除了美国，各个地区的天然气价格都紧随油价涨落。