Hydrocarbon generation characteristics and exploration prospects of Proterozoic source rocks in China
Hydrocarbon generation characteristics and exploration prospects of Proterozoic source rocks in China
复制标题
中国元古界烃源岩生烃特征及勘探前景
DOI：
10.1007/s11430-018-9312-4
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Wang Tongshan
中科院分区：
文献类型：
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作者：
Zhao Wenzhi;Wang Xiaomei;Hu Suyun;Zhang Shuichang;Wang Huajian;Guan Shuwei;Ye Yuntao;Ren Rong;Wang Tongshan
在全球元古界地层中发现了大量的原生油气藏。中国地区广泛分布着元古界层序，四川盆地震旦系大型气藏和中国北部中元古界液态油渗漏的发现，说明元古界地层的勘探潜力值得重视。本文讨论了元古界烃源岩的主要控制因素。主要是，活跃的大气环流和天文循环可能驱动了强烈的上升流和径流以提供营养；含氧的海洋表层水可能为生物的繁衍提供了合适的环境；火山活动和大陆解体造成的陆地风化将向海洋注入大量营养物质，导致海洋生物持续繁殖；大面积缺氧的深水可能为保存有机物创造了理想的条件。此外，真核生物的出现导致了油气母质的多样化，有效地提高了油气的生成潜力。通过不同克拉通地层对比，在中国地区识别出7套元古界富含有机质的烃源岩，它们主要发育于间冰期，在世界范围内也具有可比性。中国北部的红水庄组和下马岭组已被确定为中元古代烃源岩。早元古代长城系是鄂尔多斯盆地极具潜力的生油岩。上扬子地区新元古代大塘坡组和陡山沱组分布广泛，是四川盆地震旦系气藏的主要烃源岩。此外，塔里木盆地南环系可能含有丰富的高有机质页岩，但这种可能性仍需验证。实际上，这三个克拉通都可能含有元古界地层的烃源岩，因此，这些地层是值得高度关注的主要勘探目标。
A large number of primary oil and gas reservoirs have been discovered in Proterozoic strata all over the globe. Proterozoic sequences are widely distributed in China, and the discovery of large Sinian-aged gas reservoirs in the Sichuan Basin and Mesoproterozoic liquid oil seepages in North China shows that attention should be paid to the exploration potential of Proterozoic strata. In this paper, the main controlling factors of Proterozoic source rocks are discussed. Principally, active atmospheric circulation and astronomical cycles may have driven intense upwelling and runoff to provide nutrients; oxygenated oceanic surface waters could have provided suitable environments for the organisms to thrive; volcanic activity and terrestrial weathering caused by continental break-up would have injected large amounts of nutrients into the ocean, leading to persistent blooms of marine organisms; and extensive anoxic deep waters may have created ideal conditions for the preservation of organic matter. Additionally, the appearance of eukaryotes resulted in diversified hydrocarbon parent material, which effectively improved the generation potential for oil and gas. Through the comparison of Formations across different cratons, seven sets of Proterozoic organic-rich source rocks have been recognized in China, which mainly developed during interglacial periods and are also comparable worldwide. The Hongshuizhuang and Xiamaling Formations in North China have already been identified previously as Mesoproterozoic source rocks. The early Proterozoic Changchengian System is highly promising as a potential source rock in the Ordos Basin. In the Upper Yangtze area, the Neoproterozoic Datangpo and Doushantuo Formations are extensively distributed, and represent the major source rocks for Sinian gas reservoirs in the Sichuan Basin. Moreover, the Nanhuan System may contain abundant shales with high organic matter contents in the Tarim Basin, although this possibility still needs to be verified. Indeed, all three cratons may contain source rocks of Proterozoic strata; thus, these strata represent major exploration targets worthy of great attention.