王洪才, 李三忠, 刘鑫, 索艳慧, 戴黎明, 程世秀, 许立青. 南海北部陆缘盆地群新生代构造过程与油气运聚规律[J]. 海洋地质与第四纪地质, 2013, 33(1): 73-82. DOI: 10.3724/SP.J.1140.2013.01073
引用本文: 王洪才, 李三忠, 刘鑫, 索艳慧, 戴黎明, 程世秀, 许立青. 南海北部陆缘盆地群新生代构造过程与油气运聚规律[J]. 海洋地质与第四纪地质, 2013, 33(1): 73-82. DOI: 10.3724/SP.J.1140.2013.01073
WANG Hongcai, LI Sanzhong, LIU Xin, SUO Yanhui, DAI Liming, CHENG Shixiu, XU Liqing. CENOZOIC GEOLOGICAL PROCESSES AND THEIR BEARING ON HYDROCARBON MIGRATION AND ACCUMULATION IN THE CONTINENTAL MARGINAL BASIN GROUP OF THE NORTHERN SOUTH CHINA SEA[J]. Marine Geology & Quaternary Geology, 2013, 33(1): 73-82. DOI: 10.3724/SP.J.1140.2013.01073
Citation: WANG Hongcai, LI Sanzhong, LIU Xin, SUO Yanhui, DAI Liming, CHENG Shixiu, XU Liqing. CENOZOIC GEOLOGICAL PROCESSES AND THEIR BEARING ON HYDROCARBON MIGRATION AND ACCUMULATION IN THE CONTINENTAL MARGINAL BASIN GROUP OF THE NORTHERN SOUTH CHINA SEA[J]. Marine Geology & Quaternary Geology, 2013, 33(1): 73-82. DOI: 10.3724/SP.J.1140.2013.01073

南海北部陆缘盆地群新生代构造过程与油气运聚规律

CENOZOIC GEOLOGICAL PROCESSES AND THEIR BEARING ON HYDROCARBON MIGRATION AND ACCUMULATION IN THE CONTINENTAL MARGINAL BASIN GROUP OF THE NORTHERN SOUTH CHINA SEA

  • 摘要: 南海北部陆缘盆地群包括莺歌海盆地、北部湾盆地、琼东南盆地、珠江口盆地和台西南盆地,均处于复杂的构造环境下,盆地的形成及演化与周围的构造过程息息相关。本文对新生代55 Ma以来的典型时期海陆格局进行了重建,在此基础之上对南海北部陆缘各盆地的油气运聚规律进行探讨,提出:(1)太平洋板块与欧亚板块、印度-澳大利亚板块与欧亚板块相互作用可以从多方面影响油气的运移。(2)自西向东,由琼东南盆地到珠江口盆地烃源岩时代相对变老埋深变大,地幔埋深也逐渐变大,生烃能力逐渐提高;自北向南,北部湾盆地、珠江口盆地和琼东南盆地的地幔平均埋深也有逐渐变深的趋势。(3)莺歌海盆地、琼东南盆地和珠江口盆地南部成为天然气富集区的原因是由于这些区域构造活动相对较微弱,坳陷幅度小,长期处于沉降速率小的条件下,而且地壳非常薄(Moho面埋深均低于24 km),地温梯度及大地热流值偏高,有利于形成烃源岩有机质热演化多处在成熟-高熟凝析油及湿气阶段。(4)琼东南盆地和珠江口盆地具有更好的油气前景。具体来说琼东南盆地和珠江口盆地南部可成为该区极具潜力的天然气产区,而珠江口盆地北部则具有极大的石油开发潜力。

     

    Abstract: The northern continental marginal basin group of the Southern China Sea, which includes the Yinggehai Basin, the Beibuwan Basin, the Qiongdongnan Basin, the Pearl River Mouth Basin and the Taixi'nan Basin, are located in a very complex geological setting. The formation and evolution of these basins are closely related to the surrounding geological processes. This paper reconstructed the paleo-geographical framework of some key time boundaries since 55 Ma, based on which simply discussion was paid to the migration and accumulation of oil and gas in the area. Following conclusions are reached. (1) The interaction among the Pacific Plate, the Eurasia Plate and the India-Australia Plate affects the formation, migration and accumulation of hydrocarbon in this area. (2) Source rocks are gradually getting younger, as the source rocks and the Mohos are getting deeper from west to east in the Pearl River Mouth Basin, Qiongdongnan Basin and Yinggehai Basin. At the same time, heat flows as well as the potentials of hydrocarbon generation increased. Similar trend of mantle depths are observed in the Beibuwan Basin, the Pearl River Mouth Basin and the Qiongdongnan Basin from north to south. (3) Oil and gas are enriched in the Yinggehai Basin, Qiongdongnan Basin and southern Perl River Mouth Basin while the geological activities are weak, the subsidence is small and the crust is thin (the Moho depths are less than 24km) so that the geothermal gradients and the heat flows are high in this region. Such conditions can keep the organic matters remained mature or over-mature, which are favorable for the formation of gas source rocks. (4) The hydrocarbon in the Qiongdongnan Basin and the Pearl River Mouth Basin is more prospective than that in the other basins. Especially, the Qiongdongnan Basin and the southern Pearl River Mouth Basin are likely to be the important gas producing area while the northern Pearl River Mouth Basin bears higher oil producing potential.

     

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