The Theory of Hydrocarbon Genernation Controlled by Source Rock and Heat from Circle Distribution of Outsideoil Fields and Insidegas Fields in South China Sea
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摘要: 南海海域新生代经历印支—南海地台裂谷期、陆间裂谷期和区域沉降阶段，形成大陆架、大陆坡和洋壳区三大区域构造单元。围绕洋壳区，大陆坡和大陆架呈准环带状分布格局。沉积盆地主要分布在大陆架和大陆坡上，亦环绕中央洋壳区呈环带状分布。南海油气勘探活动于20世纪60年代末期开始，截至目前已发现数百个油气田，这些油气田主要分布在南部、北部和西部等大陆边缘。油气田分布主要呈大陆架或其近陆部分以油田为主、大陆坡（也包括邻近大陆架部分区域）以气田为主的“外油内气”特征。油环区凹陷烃源岩以中深湖相泥岩或深海相泥岩为主，沉积有机质以Ⅰ、Ⅱ1型干酪根为主，地壳相对较厚、热流值相对较低、烃源岩主要处在生油窗以内，烃类产物主要是原油。气环区生烃凹陷烃源岩以海陆过渡相泥岩和海相烃源岩为主，沉积有机质主要是Ⅱ2—Ⅲ型干酪根，地壳厚度相对较薄，热流值高，具“超热盆”特征，烃源岩以生气为主。油环区主力储层是砂岩，形成于湖相到浅海环境，存在多套储盖组合。气环区内带存在浅水沉积和深水沉积两套储盖组合，以深水扇和生物礁储层为主，盖层主要为海相泥岩。以300 m水深为界，油环带主要位于浅水区，勘探程度较高；内带气环主要位于陆架下部及陆坡区，勘探程度较低。南海海域勘探领域正在由浅水区向深水区发展。南海油气资源丰富，有望成为我国新的大油气区。
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关键词:
- 南海油田分布气田分布
Abstract: After experiencing threephase tectonic evolution in the Cenozoic, respectively Indiananhai rift period, intercontinent rift period and regional subsidence stage, the South China Sea (in short the SCS) possesses of three tectonic units, respectively continental shelf, continental slope and ocean crust. Surrounding the ocean crust, the distribution of the continental shelf and the continental slope is approximate to ringzone. The sedimentary basins are mainly located in the continental shelf and the continental slope. The basins surround to the center ocean crust zone, too. In the SCS, the action of the petroleum exploration flourished from the end of the 60s in last century and the hundreds hydrocarbon fields, located in the south\\north\\west continental margin, have been discovered so far. Those hydrocarbon fields character as the outsideoil and the insidegas. The oil fields locate mainly in the continental shelf or the area near the land. The gas fields locate mainly in the continental slope or the area near the ocean. In the sags which located in the outsideoil belts, the middledeep lake face mud and Ⅰ&Ⅱ1 types kerogen are dominated in the source rocks. In those sags, the crust is relatively thick and the heat flow is relatively lower. The source rocks are in the oilwindow and produce the crude oil. In the sags which located in the innersidegas belts, the marine facies mud & the onshoreoffshore mud and Ⅱ2Ⅲ types kerogen are dominated in the source rocks. In those sags, the crust is relatively thin and the heat flow is relatively higher. The source rocks produce mainly the gas. In the outsideoil zone, there are several petroleum plays. The sandstone, which formed in the environment of the lake and the shallow marine, is the main reservoir. In the innersidegas zone, there are two petroleum plays, respectively the shallow water sediments and the deep water sediments. The deepwater fan and the reef are the main reservoir. The seal is mainly the marinefacies mud stone. According to the 300m depth, the outsideoil zone, with high exploration, locates mainly in shallow water. The insidegas zone, with lower exploration, locates mainly in the bottom of the continental shelf and the continental slope. Nowadays, in the SCS, the exploration is transferring from the shallow water area to the deepwater area. With the development of petroleum exploration, the SCS, with the enormous hydrocarbon resource that is comparative to that in the rift area in the eastern China or in the Bohai gulf basins, would be the significant potential hydrocarbon area. -
Key words:
- South China Sea
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