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海洋沉积盆地是地球系统中重要的构造单元之一,其形成演化涉及到壳—幔、岩石圈—软流圈以及沉积地层和沉积流体体系等一系列深浅部耦合作用和地球动力学机制的演变。海洋沉积盆地的研究既包括地球深部结构状态、物质组成和构造演化等区域构造方面,也包括盆地内部结构、构造特征以及沉积地层孔隙流体特征等盆地自身构造特征。海底地震仪(Ocean Bottom Seismometer,OBS)广角地震探测,以其深度上穿透能力强和能够同时获取P波和S波速度结构等方面的优势,近年来在海洋沉积盆地区域构造演化、内部结构与构造以及沉积地层孔隙流体发育特征等研究中发挥了越来越重要的作用。在张裂大陆边缘的研究中,OBS广角地震探测所获取的地壳结构模型为划分“火山型”和“非火山型”张裂陆缘提供了直接证据,地壳拉张减薄的程度和空间变化特征为海洋沉积盆地构造演化的动力学模拟提供了约束条件。在盆地内部结构和构造特征方面,OBS深地震探测对盆地内部的盐体构造、岩浆底辟构造等提供了有效成像,并获取了盆地内部超压状态的分布特征,弥补了常规多道地震在探测深度和复杂地质构造背景等方面的缺陷。在海洋沉积盆地内部流体体系的研究方面,OBS深地震探测揭示了天然气水合物储集区的速度结构,进而计算获取了储集区的厚度以及水合物和游离气体在孔隙中的含量。当然,随着OBS地震探测技术的发展、数据处理能力的提高以及仪器设备参数的改善等,未来OBS广角地震探测在海洋沉积盆地动力学演化过程和机制方面的研究中将继续发挥更大更广泛的作用。
The marine sedimentary basin is one of the important tectonic units in the earth system. Its formation and evolution involve the evolution of a series of deep-shallow couplings and geodynamic mechanisms such as crust-mantle, lithosphere-asthenosphere, sedimentary strata and sedimentary fluid systems . The study of marine sedimentary basins includes not only regional structures such as the deep structure state, material composition and tectonic evolution of the Earth, but also the basin’s own structural features such as basin’s internal structure, structural features and pore fluid characteristics of sedimentary formations. The wide-angle seismic exploration of Ocean Bottom Seismometer (OBS) has the advantage of penetrating deep in its depth and acquiring both P-wave and S-wave velocity structures. In recent years, it has been widely used in marine sedimentary basins, And structural and pore fluid development characteristics of sedimentary strata and other studies have played an increasingly important role. In the study of the rifted continental margin, the crustal structural models obtained by the OBS wide-angle seismic exploration provide direct evidence for the division of “volcanic” and “” non-volcanic "fractured margins, with the crustal extension The degree and spatial variation provide the constraints for the dynamic simulation of tectonic evolution of marine sedimentary basins. In terms of the internal structure and tectonic features of the basin, the deep seismic exploration of OBS provided effective imaging of the salt body structure and magmatic diapir structure in the basin and obtained the distribution characteristics of the overpressure in the basin, which made up for the conventional multi-channel seismic Exploration depth and complex geological structure of the defects. In the study of fluid systems in marine sedimentary basins, deep seismic exploration in OBS reveals the velocity structure of gas hydrate reservoirs, and then calculates the thickness of reservoir and the content of hydrate and free gas in pores. Of course, with the development of OBS seismic exploration technology, the improvement of data processing capability and the improvement of equipment parameters, the future OBS wide-angle seismic exploration will continue to play a larger and wider role in the research on the process and mechanism of dynamic evolution of marine sedimentary basins Role.