| 川东南南川地区构造变形与页岩气富集 |
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| 引用本文： | 汤济广,汪凯明,秦德超,张玥,冯涛.川东南南川地区构造变形与页岩气富集[J].地质科技通报,2021,40(5):11-21. |
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| 作者姓名： | 汤济广 汪凯明 秦德超 张玥 冯涛 |
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| 基金项目： | 国家科技重大专项2017ZX05008-006-005-002 |
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| 摘 要： | 南川地区自下古生界海相页岩成气以来，遭受了强烈的构造改造作用，致使页岩气富集规律复杂。为揭示南川地区中新生代构造变形对页岩气富集的制约，通过构造精细解析，以及对演化时序和页岩气富集主控因素的分析，构建了结构模式，恢复了中新生代构造演化过程，厘定了页岩气富集主控因素，进而分析了构造样式与页岩气富集模式的响应关系。研究表明，南川地区整体构造变形自东向西逐渐减弱，存在北段强烈冲断褶皱-断展-断滑、南段强烈冲断褶皱-断滑两种前展式结构模式。中燕山期，主体NE向构造发育，平桥、东胜构造形成，至中燕山期末期，受金佛山隆起以及南川-遵义断层的作用，南段发生构造叠加与改造，早期NE向构造演化为北倾单斜，并在南川-遵义断层东侧发育近南北向阳春沟背斜。受差异构造变形作用，北段断褶带发育背斜型富页岩气构造样式，外缘带为单斜型构造样式，而南段构造叠加带则发育单斜型和背斜型构造样式。页岩气整体保存条件受构造变形方式制约，北段页岩气保存条件由东向西逐渐变好，而南段页岩气保存条件较为复杂，其中北段的低角度单斜、宽缓背斜、较宽缓背斜3类构造样式为有利的页岩气富集构造。
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| 关 键 词： | 页岩气 构造变形 前展式结构模式 保存 富集 南川地区 |
| 收稿时间： | 2021-06-08 |
Tectonic deformation and its constraints to shale gas accumulation in Nanchuan area,southeastern Sichuan Basin |
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| Abstract: | Since the gas generation of Lower Paleozoic marine shale, it has suffered from strong structural transformation, resulting in complex enrichment law of shale gas in Nanchuan area. In order to reveal the constraints of Mesozoic and Cenozoic tectonic deformation to shale gas enrichment, through fine structural analysis, and the analysis of evolution time series, and main controlling factors of shale gas enrichment, the structural model is constructed, the Mesozoic and Cenozoic tectonic evolution process is restored, the main controlling factors of shale gas enrichment are determined, and then the response relationship between structural style and shale gas enrichment model is analyzed. The study shows that the tectonic deformation strength gradually weakens from east to west in Nanchuan area, and there are two propagation structural modes: strong thrust fold-break-slip in the northern section and strong thrust fold-break slip in the south ones.In the middle Yanshan period, the main NE trending structures were developed, and Pingqiao and Dongsheng structures were formed in the time. At the end of the middle Yanshan period, due to Jinfoshan uplift and Nanchuan-Zunyi fault, the southern section underwent structural superposition and transformation. The early NE trending structure evolved into a north dipping monocline, and a nearly SN Yangchungou anticline was developed on the east side of Nanchuan-Zunyi fault. Due to differential structural deformation, anticlinal shale gas rich structural style is developed in the fault fold belt, and the shale gas rich structural style is monoclinic in the outer edge belt in the north section, while monoclinic and anticline ones are developed in the structural superposition belt in the southern section. The preservation conditions of shale gas are restricted by the structural deformation mode. The preservation conditions of shale gas gradually become better from east to west in the northern section, while the shale gas ones are more complex in the southern section. Among them, three structural styles such as low angle monocline, wide and gentle anticline and wide and gentle anticline are favorable shale gas enrichment structures in the northern section. |
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