从阿巴拉契亚--阿钦塔造山带看中国北方大陆南缘古生代的油气前景

Hydrocarbon potential of the southern margin of North China continent based on reservoir model of the Appalachianhian-Ouachita Overthrust belts.

阿巴拉契亚—阿钦塔造山带是北美乃至世界著名的大陆边缘挤压碰撞推覆造山带,是地质学研究的经典地区之一,也是许多经典地学理论和概念的发源地。其中,对地质学影响最大的当属地槽学说。继20世纪60年代由深海钻探带来地学革命之后,由COCORP实施的地震反射剖面和深钻揭示了该造山带的巨大推覆构造。人们惊奇地发现,在巨大推覆体之下的大陆边缘,广泛分布着古生代浅水碳酸盐岩地层并具有巨大油气潜力。于是很多油气公司调整了这些地区油气勘探的战略部署,很快在推覆体之下早古生代地层中得到油气勘探的突破。其中,威尔伯顿(Wilburton)油气田就是当时美国发现的最大油气田之一,其单井天然气日产量有的超过1亿立方英尺。通过综合对比,笔者认为中国北方大陆南部边缘的大别—秦(岭)祁(连)—昆仑这一东西延伸的造山带与美国阿巴拉契亚—阿钦塔推覆大陆边缘在地层、岩相和盆地构造演化史等诸多方面有着惊人的相似性和可比性,是发生在中国北方巨大大陆南缘的古生代挤压碰撞推覆造山带。在许多大洋深水盆地相推覆体之下的早古生代浅水碳酸盐岩地层也具有良好的油气前景。粗略估算,我国北方大陆边缘推覆体之下早古生代碳酸盐岩地层很可能达几十万km2或更多,这一潜力是不可忽视的。

The Appalachian-Ouachita Overthrust in the United States is a part of a huge orogenic belt that runs from Canada,through the Appalachian and Ouachita Mountains to Mexico,which is also the region of Paleozoic deformation along the southeast side of the North American continent and bordering the central continental platform.The Appalachians were studied very early in the history of American geology,and many classical ideas have been derived from them.Since the 60＇ s-70＇ s of the 20th century,oil and gas fields have been discovered from north to south in the overthrust orogenic belt.Individual wells had initial production of over 100 million cubic feet of gas per day in Wilburton,Oklahoma.The so-called Qinling-Qilian orogenic belt,which is also traced to Dabie to the East and Kunlun to the West,is geologically similar to the Appalachian-Ouachita Overthrust in the United States on the basis of comprehensive studies of stratigraphy,lithofacies and tectonic-basin evolution from both areas.It is a Paleozoic overthrust belt of southern margin of the Paleozoic North China continent.Author believed that the overthrust belts are one of the highest potential frontiers for oil and gas discoveries in the future.