“死亡之海”下缘何藏有祖国油库

Why does the “sea of death” contain the oil depot of the motherland

塔里木盆地是我国第一大盆地,面积达56万平方公里,因自然环境极度恶劣被称为"死亡之海"。在这片贫瘠的土地下却蕴藏有丰富的石油和天然气,预测盆地内碳酸盐岩油气资源量超过2.8×109 t,目前已探明石油储量近7×108 t,探明天然气储量近1 500×108 m3,被称为国家油库。这些油气的生成是由于距今5.4亿年前的寒武纪时期塔里木盆地曾是汪洋一片,孕育有体量巨大的动植物,动植物死亡后沉积在海洋深处,奥陶纪时期盆地内沉积有碳酸盐岩。后期构造隆起运动,洋底变为陆地遭遇风化作用,奥陶系碳酸盐岩发生岩溶作用,生成岩溶缝洞系统,动植物遗体在高温高压下生成的油气就储集在这些岩溶缝洞内。在奥陶系地层之上沉积有具有封盖作用的砂泥岩,把这些调皮的"油娃娃"裹的严严实实,这就是为什么今天我们能在"死亡之海"大漠之下发现储量丰厚的油气。

Tarim basin,which covers an area of 560 000 square kilometers,is the largest basin in China.It is predicted that the amount of carbonate rock oil and gas resources in the basin is more than 2.8×10 9 t.At present,the proven oil reserves are nearly 7×10 8 t and the proved natural gas reserves are nearly 1 500×10 8 m 3,which is known as the national oil depot.The formation of these oil and gas is due to the fact that the tarim basin was once a piece of ocean in the Cambrian period 540 million years ago,which gave birth to massive animals and plants.The dead animals and plants were deposited in the deep ocean,and the carbonate rocks were deposited in the ordovician basin.In the later stage of tectonic uplift,the ocean floor changed into the land under weathering,the ordovician carbonate rocks were karst,and the karst fissure system was formed.The ordovician strata are covered with livid sand and mud,and these naughty oil dolls are packed tightly together,which is why today we find substantial reserves of oil and gas beneath the desert of the sea of death.