| 下扬子中生代构造-热事件及其对海相烃源岩生烃的影响 |
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| 引用本文： | 袁玉松,俞昊,李天义,李双建.下扬子中生代构造-热事件及其对海相烃源岩生烃的影响[J].地球物理学报,2016,59(6):2191-2202. |
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| 作者姓名： | 袁玉松 俞昊 李天义 李双建 |
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| 作者单位： | 1. 中国石油化工股份有限公司石油勘探开发研究院, 北京 100083;2. 中国石油化工股份有限公司华东分公司勘探开发研究院, 南京 210011 |
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| 基金项目： | 国家重大专项(2015ZX05061001)和国家973项目(2012CB214806)资助. |
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| 摘 要： | 温度是控制烃源岩有机质生烃的主要因素,构造-热事件下的高温作用对烃源岩的增熟和生烃历程具有显著影响.通过地质分析和磷灰石、锆石裂变径迹、磷灰石U-Th/He低温热年代学数据、火山岩年龄数据分析认为,下扬子中生代存在印支期(T_3-J_2),燕山期(J_3-K_1)构造-热事件,沉积盆地达到最高古热流的时间大约为130~110Ma.古温标镜质体反射率热史反演结果揭示句容地区最高地表古热流达到~94mW·m~(-2),泰兴地区为~78mW·m~(-2),热事件的强度由西至东减弱.基于EASY%Ro模型的生烃史正演结果揭示:寒武系烃源岩在常州地区主生气期为早二叠世晚期至晚三叠世末,在句容、泰兴地区主生气期为晚三叠世-早白垩世.由于T_3-J_(1-2)前陆盆地沉积和早白垩世岩浆活动热事件的双重作用,海相烃源岩有机质在早白垩世末达到最高古地温.虽然K_2-E期间在句容、泰兴和常州部分地区具有一定的沉降幅度,甚至使得部分地区海相烃源岩的埋深超过早期的埋深,但由于K_2以来大地热流降低,海相烃源层地层温度却低于早期的地温,有机质未能普遍进一步增熟生烃,即这些地区不存在大面积的二次生烃.
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| 关 键 词： | 下扬子 热事件 裂变径迹 古热流 二次生烃 |
| 收稿时间： | 2015-12-11 |
Mesozoic tectonothermal events in central Lower Yangtze area and impacts on hydrocarbon generation of marine source rocks |
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| YUAN Yu-Song,YU Hao,LI Tian-Yi,LI Shuang-Jian.Mesozoic tectonothermal events in central Lower Yangtze area and impacts on hydrocarbon generation of marine source rocks[J].Chinese Journal of Geophysics,2016,59(6):2191-2202. |
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| Authors: | YUAN Yu-Song YU Hao LI Tian-Yi LI Shuang-Jian |
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| Institution: | 1. Petroleum Exploration and Production Research Institute, SINOPEC, Beijing 100083, China;2. Petroleum Exploration and Production Research Institute of East China Branch, SINOPEC, Nanjing 210011, China |
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| Abstract: | Temperature is a key parameter of controlling hydrocarbon generation of source rocks. Elevated temperature resulted from tectonothermal events may significantly affect hydrocarbon generation. Based on geology, fission track analysis, apatite U-Th/He and volcanic rock isotopic age data, there existed Indosinian (T3-J2) and Yanshanian (J3-K1) tectonothermal events in Lower Yangtze area and the sedimentary basins reached their peak heat flow at about 130~110 Ma. The maximum heat flows obtained from thermal history reconstruction based on vitrinite reflectance are ~94 mW·m-2 and ~78 mW·m-2 in Jurong and Taixin areas respectively, with an increasing trend from east to west. Hydrocarbon generation history reconstruction based on the EASY%Ro model shows that the dominating gas generation periods of the Cambrian source rocks are the Early Permian-Late Triassic and the Late Triassic-Early Cretaceous in Changzhou and Jurong areas respectively. Because of the dual effects from the foreland sediments deposited in T3-J1-2 and the magmatism thermal event in the Early Cretaceous, the marine source rocks reached their maximum temperature at the end of Early Cretaceous. The temperature of the marine source rocks was no longer elevated owing to the decreased heat flow since the Late Cretaceous, though, in some parts of the Jurong, Taixin and Changzhou areas, subsidence occurred and burial depth increased during the K2-E period. Therefore, the secondary hydrocarbon generation of the marine source rocks did not widely occur in the central Lower Yangtze area. |
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| Keywords: | Lower Yangtze Thermal event Fission track Paleo-heat flow Secondary hydrocarbon generation |
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