Tectonic Dynamics of Cenozoic Sedimentary Basins and Hydrocarbon Resources in the South China Sea
Tectonic Dynamics of Cenozoic Sedimentary Basins and Hydrocarbon Resources in the South China Sea
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发表时间：
2004
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通讯作者：
Liu Zhen-hu
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作者：
Liu Zhen-hu
通过对南海南部与北方构造环境、油气藏、生盖组合等方面的对比，探讨了南海油气分布特征，以论证南海油气勘探方向。从目前的油气勘探情况看，南海南缘的油气勘探前景好于北方。造成这种差异的可能原因可以分为以下几个方面。第一，华南南部边缘新生代为挤压环境，烃源岩体积大于北方边缘的被动环境。其次，南缘的热流和地温梯度高于北方，如北方大陆架珠江口盆地的热流为53-87 mW/m2，平均值为67 mW/m2，而南缘曾母盆地的热流平均值为97 mW/m2，最大值为130 mW/m2。这一事实表明，南缘烃源岩的成熟度高于北方。新生代挤压环境下，南缘形成了许多大型含油构造，而北方伸展环境下的圈闭构造数量少、规模小。最后，圈闭构造形成时间与生烃时间的协调性，南缘也好于北方。目前的油气勘探也表明，南缘存在一批大型油气田，北方缘只有中、小型油气田。因此，南海南缘的油气远景比北方要丰富。
This paper discusses the distributing characteristics of petroleum in the South China Sea by comparing on the tectonic environments, the assemble of reservoirs, source and cap rocks between the southern and northern South China Sea in order to demonstrate the exploration guide of the petroleum. Petroleum potential in the southern margin of the South China Sea is better than that in the northern margin according to present petroleum exploration. Possible reasons causing such a difference may be grouped into the following aspects. Firstly, the southern South China margin belongs to an extruding environment in Cenozoic time, where the volume of source rocks is bigger than that in the northern margin belonging to a passive environment. Secondly, heat flow and geothermal gradient in the southern margin are higher than those in the northern margin, for example, heat flow in the Pearl River Mouth basin on the shelf of northern margin is 53-87 mW/m~2 with an average value of 67 mW/m~2; but in the Zengmu basin in the southern margin,an average heat flow is 97 mW/m~2 with a maximum value of 130 mW/m~2. This fact indicates that the maturation of source rocks in the southern margin is higher than that in the northern margin. Thirdly, many large scale oil-bearing structures in the southern margin are formed due to the extruding environments in Cenozoic time, but trap structures in the northern margin are relatively little in quantity and small in scale in extension environments. Finally, the coordination between the formation time of trap structures and hydrocarbon-generating time in the southern margin is also better than that in the northern margin. Present hydrocarbon exploration also shows that a number of big oil and gas fields exist in the southern margin, only medium-little oil and gas fields occur in the northern margin. Therefore, petroleum potential in the southern margin is richer than that in the northern margin of the South China Sea.