南海北部与南部新生代沉积盆地热流分布与油气运聚富集关系  

DISTRIBUTION OF HEAT FLOW IN CENOZOIC BASINS OF SOUTH CHINA SEA AND ITS CONNECTION WITH OIL AND GAS MIGRATION AND ACCUMULATION

作　　者：徐行[1] 何家雄[2] 何丽娟[3] 龚晓峰[2] 

机构地区：[1]国土资源部广州海洋地质调查局,广州510075 [2]中国科学院边缘海地质重点实验室,广州510640 [3]中国科学院地质与地球物理研究所,北京100029

出　　处：《海洋地质与第四纪地质》2011年第6期99-108,共10页Marine Geology & Quaternary Geology

基　　金：国家高技术研究发展计划(2006AA09A203);国家自然科学基金项目(41040043)

摘　　要：南海处于欧亚、印度-澳大利亚及太平洋三大板块相互作用的特殊构造位置,区域地质背景及地球动力学条件复杂,不同类型大陆边缘盆地深部地壳属性与大地热流分布均差异明显:北部大陆边缘以拉张裂陷型为主,形成了具典型断坳双层结构的断陷裂谷盆地,由于处在减薄型陆壳及洋陆过渡型地壳位置,深部地壳自北向南逐渐减薄,大地热流值由北至南逐渐递增,油气分布则具有"北油南气"的运聚富集规律;南部及西南部大陆边缘属拗曲—伸展与挤压和走滑多因素混合成因的复合叠置型边缘,形成了拗曲—伸展与挤压复合盆地和走滑伸展型复合盆地,由于处在复杂的洋陆过渡型地壳及某些局部薄地壳位置,大地热流分布普遍比北部大陆边缘偏高,油气分布以富集天然气为主伴有少量凝析油及轻质油。因此,该区迄今勘探发现的油气,主要为天然气田及油气田而油田偏少。总之,区域地质背景及深部地壳性质和地壳厚度变化等,导致不同区域大地热流分布差异明显,进而最终控制和制约了油气分布与运聚富集规律,换言之,区域地质背景及大地热流分布与油气运聚富集存在密切的成因联系和耦合关系。The South China Sea is located in the juncture of the three tectonic blocks of Eurasia, India-Australia and the Pacific. The regional geological background and earth dynamic conditions are rather compli caled. The characteristics of deep crust vary in different types of continental margin, and as the result the distribution of heat flow are of difference significantly. The north continental margin of the South China Sea is prevailed by rift basins with typical double layer structure. With the thining of the continental crust from north to south, and the occurrence of transitional crust, heat flow increases accordingly. Taking the distribution of hydrocarbon into account, there is oil in the north and gas in the south. However, the south and southwest continental margin of the South China Sea is a composite continental margin under a complicated dynamic condition characterized by the superimposition of bending stretching, compression and strike sliping. There form the bending stretching and compression composite basins and strike sli ping composite basins. Heat flow is higher here rather than in the north continental margin. Therefore, this region is rich in gas with a small amount of condensate oil and light oil. Many gas fields but a little of oil fields have been discovered. Data suggest that heat flow is one of the controlling factors on oil and gas migration, accumulation and distribution. And the distribution pattern of heat flux depends on the geolog ical background, the nature of deep crust and the alteration of earth＇s crust thickness of the region. Oil and gas accumulation and distribution are closely related to the heat flow distribution pattern.

关 键 词：大陆边缘类型 大地热流分布 油气富集规律 成因耦合关系 南海 

分 类 号：P744.4[天文地球—海洋科学]