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海洋拖缆主动源多道地震技术是应用于海洋天然气水合物资源调查的主要技术方法。不同于常规油气藏勘探,海底天然气水合物成藏机制复杂多样,海底似反射(Bottom Simulating Reflector,BSR)特征与水合物赋存并非完全对应。为提高海洋天然气水合物矿体识别的可靠性,地震属性技术在水合物资源调查中发挥着越来越重要的作用。本文对我国南海北部海域天然气水合物调查中的关键属性进行了对比、分析及筛选试验研究。试验针对海洋高分辨多道三维地震数据,采用三维地震层速度控制综合处理技术完成了BSR区域的成像,提取了与BSR相关的多种地震属性,并对BSR地震属性体的内部特性进行了分析,实现了BSR特征水合物矿体的识别,并提取了BSR上方和下部结合层带的地震属性。研究结果表明,在水合物赋存地层极其复杂的条件下,地震属性分析技术在海洋复杂浅地层水合物识别方面具有可行性和技术优势。 相似文献
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《中国海洋大学学报(自然科学版)》2016,(10)
为了提高地震剖面上天然气水合物识别的可信度,以神狐海域天然气水合物钻探结果为基础,首次将剩余静校正处理技术应用于天然气水合物地震资料处理中。结果显示,在经过剩余静校正处理后的地震剖面上BSR特征清晰,反射能量强,极性反转明显。在此基础上,对比分析了过神狐海域2口水合物钻井的新老剖面品质,对比结果显示,不论是钻遇天然气水合物的SH3井,还是未钻遇天然气水合物的SH1井,经过剩余静校正处理后的新剖面成像精度得到了明显提高,剖面显示出的细微结构更加清晰,有利于天然气水合物的识别。因此,建议开展海域天然气水合物(尤其是扩散型水合物)的剩余静校正处理。 相似文献
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小道距高分辨率多道地震对天然气水合物勘查的适用性 总被引：1，自引：0，他引：1
《海洋地质前沿》2015,(6)
在海底以下100~1 100m的沉积层的地质勘探中,小道距高分辨率多道地震勘探可以获得高信噪比、高分辨率的地震资料。选取合适的地震采集参数,小道距高分辨率多道地震采集技术同样适用于天然气水合物勘查,针对水合物勘探选取合适的地震采集和地震处理参数,可以提高浅部地层分辨率和水合物识别精度。海上地震采集参数设置是非常重要的,尤其是高的采样率为后续地震数据处理,提高剖面分辨率提供了可能。 相似文献
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天然气水合物将成为21世纪的替代能源，地球物理方法是勘探天然气水合物的重要手段。本文比较全面地分析和总结了天然气水合物的各种地球物理识别技术以及地震资料的特殊处理和分析方法，详细地介绍了水平地震剖面、垂直地震剖面、测井以及旁侧声纳剖面上天然气水合物的表现和识别方法。特别地，针对海洋地震资料的特点以及天然气水合物在地震剖面上的识别标志BSR、振幅空白带等特征，文章引入了真振幅处理、子波处理以及多项式拟合等处理方法来提高天然气水合物识别标志在地震剖面上的显示效果。最后，为了全面了解海底天然气水合物的分布 以及微细结构，文章介绍了AVO分析、全波形反演速率分析、叠加速度分析和走时反演等正、反演技术。 相似文献
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地震勘探是探测海底天然气水合物的重要手段,利用地震资料的诸多特征可以较好地识别海底天然气水合物,尤其是在识别似海底反射(BSR)方面发挥着重要作用.由于多次波等特征与BSR有很多相似之处,如果辨别不当就很容易被误认为是BSR,将会得出错误的结论.以我国某海域实际资料为例,从研究BSR的地震特征出发,指明多次波、气泡效应等多种假BSR现象,提出了利用精细速度分析、AVO特征分析、多次波压制等多种地震参数约束以识别真假BSR,进而提高海洋地震勘探精度,为寻找更多的海底天然气水合物提供技术保障. 相似文献
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用于研究东海天然气水合物的地震资料处理方法 总被引：3，自引：0，他引：3
通过对东海海域二维地震、单道地震、浅层剖面等资料进行的综合研究表明 :用于研究天然气水合物的地震资料处理应提高速度分析精度和分辨能力 ,进行子波估算 ,压制多次波 ,相对保持振幅 ,DMO,AVO及波阻抗特殊处理等。在地震剖面上天然气水合物主要特征有 :BSR、振幅异常、速度异常、AVO异常等标志特征。据此 ,可对天然气水合物进行识别和预测。东海海域是天然气水合物可能赋存的有利部位 ,其中冲绳海槽是天然气水合物成藏的目标区域。 相似文献
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近年海域天然气水合物勘探和研究表明,水合物的形成、聚集和分布往往与浅层深水沉积体之间存在紧密联系,随着深水观测和钻探技术的提高以及高分辨三维地震资料的使用,深水沉积体系研究进入了一个快速发展的阶段,在水合物远景区域内对浅层深水沉积体进行精细刻画已成为海域天然气水合物勘探的热点和难点。通过分析国内外深水沉积体系研究现状,从浅层深水沉积体与海域天然气水合物的关系入手,对现有研究方法和手段、深水沉积体的发展趋势进行总结和分析,结合南海北部陆坡天然气水合物勘探研究现状和存在问题,提出应该在浅层深水沉积体发育类型和沉积背景、浅层深水沉积体的内部构成和空间分布、以及浅层深水沉积体与水合物耦合关系等三方面加强研究,以期为我国海域天然气水合物勘探和研究提供参考。 相似文献
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2D and 3D seismic reflection and well log data from Andaman deep water basin are analyzed to investigate geophysical evidence related to gas hydrate accumulation and saturation. Analysis of seismic data reveals the presence of a bottom simulating reflector (BSR) in the area showing all the characteristics of a classical BSR associated with gas hydrate accumulation. Double BSRs are also observed on some seismic sections of area (Area B) that suggest substantial changes in pressure–temperature (P–T) conditions in the past. The manifestation of changes in P–T conditions can also be marked by the varying gas hydrate stability zone thickness (200–650 m) in the area. The 3D seismic data of Area B located in the ponded fill, west of Alcock Rise has been pre-stack depth migrated. A significant velocity inversion across the BSR (1,950–1,650 m/s) has been observed on the velocity model obtained from pre-stack depth migration. The areas with low velocity of the order of 1,450 m/s below the BSR and high amplitudes indicate presence of dissociated or free gas beneath the hydrate layer. The amplitude variation with offset analysis of BSR depicts increase in amplitude with offset, a similar trend as observed for the BSR associated with the gas hydrate accumulations. The presence of gas hydrate shown by logging results from a drilled well for hydrocarbon exploration in Area B, where gas hydrate deposit was predicted from seismic evidence, validate our findings. The base of the hydrate layer derived from the resistivity and acoustic transit-time logs is in agreement with the depth of hydrate layer interpreted from the pre-stack depth migrated seismic section. The resistivity and acoustic transit-time logs indicate 30-m-thick hydrate layer at the depth interval of 1,865–1,895 m with 30 % hydrate saturation. The total hydrate bound gas in Area B is estimated to be 1.8 × 1010 m3, which is comparable (by volume) to the reserves in major conventional gas fields. 相似文献
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N. Sultan M. Voisset T. Marsset A.M. Vernant E. Cauquil J.L. Colliat V. Curinier 《Marine Geology》2007,240(1-4):235-255
We present a new method to characterize free gas, gas hydrates and carbonate concretions occurrence which are considered as high-risk factors for sub-sea developments in the Niger delta. This method is based on the combination of 3D seismic data to the geotechnical site characterizations using piezocone CPTU tests (Cone Penetration Test with additional measurement of the pore water pressure). A special processing of the 3D seismic data has enabled the determination of the interval compressional velocity. Using the effective-medium theory, velocity anomalies (negative and positive) within the first 15 m were translated in gas hydrate and free gas distribution. The calibration of the P wave velocity anomalies was done thanks to in-situ geotechnical testing carried out during two oceanographic surveys (2003 and 2004). Comparison between in-situ testing, recovered cores and the prediction of the gas and the gas hydrate distribution based on the compressional wave velocity have shown that 3D seismic data is a valuable tool to identify heterogeneous areas but the use of the piezocone was essential to discriminate between gas hydrate occurrences and carbonate concretions' presence. Furthermore, in-situ compressional wave velocity (Vp) measurements have clearly demonstrated what it was suspected from the 3D seismic data, the co-existence in the study area between gas hydrate and free gas. 相似文献
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大量研究表明南海北部珠江口盆地是天然气水合物发育区,但是该盆地东部揭阳凹陷水合物研究较少。本文利用揭阳凹陷新采集三维地震资料,对该三维地震资料进行成像道集优化和叠前时间偏移处理,得到针对水合物的新处理地震数据体,并通过高精度网格层析反演得到层速度数据体。利用该数据开展叠后约束稀疏脉冲反演,获得含天然气水合物地层波阻抗异常,综合分析反演与地震属性识别水合物。从新处理地震资料看,该区域似海底反射(bottom simulation reflection,BSR)反射呈连续、不连续与地层斜交等特征,BSR发育在一个继承性小型水道上,且下部断裂和气烟囱发育。通过分析BSR特征及BSR上下地层的速度、波阻抗、振幅、频率、相干等属性异常,结合水合物成藏条件,发现了南海北部新的天然气水合物有利富集区,为该区域水合物勘探提供基础。 相似文献
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AVO (Amplitude Versus Offset) is a seismic exploration technology applied to recognize lithology and detect oil and gas through analyzing the feature of amplitude variation versus offset. Gas hydrate and free gas can cause obvious AVO anomaly. To find geophysical evidence of gas hydrate and free gas in Shenhu Area, South China Sea, AVO attribute inversion method is applied. By using the method, the multiple seismic attribute profiles and AVO intercept versus gradient (I-G) cross plot are obtained. Bottom-simulating reflector (BSR) is observed beneath the seafloor, and the AVO abnormal responses reveal various seismic indicators of gas hydrate and free gas. The final AVO analysis results indicate the existence of gas hydrate and free gas in the upper and lower layers of BSR in the study area. 相似文献
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天然气水合物是天然气和水在特定条件下形成的一种透明的冰状结晶体。天然气水合物的发现为寻找清洁高效的新型能源,以取代日益枯竭的传统能源提供了一个广阔的领域和新的思维方式。我国天然气水合物具有广阔的勘探领域和良好的勘探前景。本文对天然气水合物的研究现状进行了综述。在总结前人关于天然气水合物研究的基础上,总结归纳了天然气水合物的地震、地球物理测井、沉积岩石、地球化学、地形地貌等识别标志。企望对加速天然气水合物的勘探提供一些有益的线索。 相似文献
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The northern South China Sea (NSCS) experienced continuous evolution from an active continental margin in the late Mesozoic to a stable passive continental margin in the Cenozoic. It is generally believed that the basins in the NSCS evolved as a result of Paleocene–Oligocene crustal extension and associated rifting processes. This type of sedimentary environment provides a highly favourable prerequisite for formation of large-scale oil- and gas–fields as well as gas hydrate accumulation. Based on numerous collected data, combined with the tectonic and sedimentary evolution, a preliminary summary is that primitive coal-derived gas and reworked deep gas provided an ample gas source for thermogenic gas hydrate, but the gas source in the superficial layers is derived from humic genesis. In recent years, the exploration and development of the NSCS oil, gas and gas hydrate region has provided a basis for further study. A number of 2D and 3D seismic profiles, the synthetic comparison among bottom simulating reflector (BSR) coverage characteristics, the oil-gas area, the gas maturity and the favourable hydrate-related active structural zones have provided opportunities to study more closely the accumulation and distribution of gas hydrate. The BSR has a high amplitude, with high amplitude reflections below it, which is associated with gas chimneys and pockmarks. The high amplitude reflections immediately beneath the BSR are interpreted to indicate the presence of free gas and gas hydrate. The geological and geochemical data reveal that the Cenozoic northern margin of the NSCS has developed coal-derived gas which forms an abundant supply of thermogenic gas hydrate. Deep-seated faults and active tectonic structures facilitate the gas migration and release. The thermogenic gas hydrate and biogenic gas are located at different depths, have a different gas source genesis and should be separately exploited. Based on the proven gas hydrate distribution zone, we have encircled and predicted the potential hydrate zones. Finally, we propose a simple model for the gas hydrate accumulation system in the NSCS Basin. 相似文献
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Recently, several countries have conducted projects to explore and develop natural gas hydrate, which is one of the new alternative
energy resources for the future. In Korea, a five-year national research project was initiated in 2000. As part of this project,
a seismic survey was performed in the East Sea of Korea to quantify the potential magnitude and distribution of natural gas
hydrates. Multi-channel seismic data and core samples have been acquired and recovered in the survey area. Analysis of seismic
data show clear bottom simulating reflectors (BSRs), seismic blank zones (or wipe-out zones) with velocity pull-up structure,
and pock-marks. In this study, we present the results of seismic surveys which indicate the existence of natural gas hydrates
in Korean offshore areas. These results will be applied to select areas for coring (or drilling) and detailed exploration
such as 2D seismic survey with long offset or 3D seismic in the future. 相似文献
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Bin Liu Jiangxin Chen Li Yang Minliang Duan Shengxuan Liu Yongxian Guan Pengcheng Shu 《海洋学报(英文版)》2021,40(7):183-197
To confirm the seabed fluid flow at the Haima cold seeps, an integrated study of multi-beam and seismic data reveals the morphology and fate of four bubble plumes and investigates the detailed subsurface structure of the active seepage area. The shapes of bubble plumes are not constant and influenced by the northeastward bottom currents, but the water depth where these bubble plumes disappear (630–650 m below the sea level) (mbsl) is very close to the upper limit of the gas hydrate stability zone in the water column (620 m below the sea level), as calculated from the CTD data within the study area, supporting the “hydrate skin” hypothesis. Gas chimneys directly below the bottom simulating reflectors, found at most sites, are speculated as essential pathways for both thermogenic gas and biogenic gas migrating from deep formations to the gas hydrate stability zone. The fracture network on the top of the basement uplift may be heavily gas-charged, which accounts for the chimney with several kilometers in diameter (beneath Plumes B and C). The much smaller gas chimney (beneath Plume D) may stem from gas saturated localized strong permeability zone. High-resolution seismic profiles reveal pipe-like structures, characterized by stacked localized amplitude anomalies, just beneath all the plumes, which act as the fluid conduits conveying gas from the gas hydrate-bearing sediments to the seafloor, feeding the gas plumes. The differences between these pipe-like structures indicate the dynamic process of gas seepage, which may be controlled by the build-up and dissipation of pore pressure. The 3D seismic data show high saturated gas hydrates with high RMS amplitude tend to cluster on the periphery of the gas chimney. Understanding the fluid migration and hydrate accumulation pattern of the Haima cold seeps can aid in the further exploration and study on the dynamic gas hydrate system in the South China Sea. 相似文献
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天然气水合物准三维地震调查导航定位技术 总被引：2，自引：0，他引：2
随着我国天然气水合物调查工作进展到需要实施钻探阶段,为了进一步提高水合物识别的准确度,精确描述水合物矿体的外部形态及展布特征,获取矿体准确的位置信息,必须要提高导航定位的精度。在水合物调查的实践过程中,根据单源单缆准三维地震的特殊性,通过对定位网络配置、误差分析、数据处理等技术方法的建立,有效地提高了定位精度并在实际的工作实践中取得了明显的效果,为水合物的获取提供了有力的技术支持。 相似文献