第84届SEG年会多分量地震技术评述

综合分析2014年度美国SEG年会上多分量地震技术方面的学术论文,不难发现:在多波地震偏移成像研究中,叠前时间偏移仍是实际应用的主要方法;相比于PS折射波初至拾取,径向-道域变换的射线路径一致性静校正方法效果更好;全波形反演在四维地震应用中具有诱人的前景,基于纵波反射系数的流体因子反演方法在稳定性、准确性方面显示出很大的优势,有望产生实际的应用效果。多分量地震技术的发展特点可归纳为"一批亮点,一个重点",即:页岩的岩石物理实验与数值模拟分析、地震波的低频衰减气溶机理、六分量矢量波场特征的研究、多组多尺度裂缝系统的响应特征是该领域研究的亮点;综合利用海洋四分量压制鬼波及径向波、去除海底多次波、提高纵波的信噪比是海洋多分量地震技术发展的重点。      

多分量转换波地震勘探初探

多分量地震勘探的理论方法研究起步较早,其中多分量转换波地震勘探由于其投资小、获取地下信息多的原因。近几年逐渐成为地震勘探领域的研究热点。此外,由于多分量勘探可以同时提供纵波和横波的速度信息,使岩性研究成为可能;快慢横波的分离和分裂时差又额外地给我们提供了进行非均质性介质弹性参数反演的可能,包括各向异性因子、裂缝的发育方向和发育密度。总之,多分量转换波地震勘探使我们在常规地震勘探的投资框架下,使岩性、缝洞型储层的发现及开发地震的量化成为可能。在本篇文章中,我们简单介绍这项理论方法技术。以及多分量转换波地震的发展现状及前景。     

莺歌海盆地地层各向异性多波地震判别技术研究

充分利用中国在海上采集到的多波地震资料:PZ分量(P波)时间偏移剖面、X分量(P-SV波)时间偏移剖面和Y分量(P-SH波)时间偏移剖面,对莺歌海盆地3个构造(A构造、B构造、C构造)和D砂体的地下岩石介质的各向异性特征进行了研究,Y分量(P-SH波)、X分量(P-SV波)的旅行时间闭合差、准各向异性系数和泊松比结果表明A构造、B构造、C构造等存在不同程度的各向异性,且A构造的各向异性最强.实践证明,在海洋石油勘探中,多波地震资料用于地下岩石介质各向异性的判别是可行的.     

多分量地震勘探技术的现状及进展

多分量地震勘探技术发展到今天，经历了漫长的历程。近年来，海上多波勘探的成功极大地推动了这一技术的发展。人们注意到这一技术比单一纵波勘探能提供更多的地震属性信息，能够解决储层的岩性、孔渗以及裂缝裂隙的密度和方向等问题。国内外研究学者在各向异性理论、地震波的传播机理、数值模拟、多分量地震资料的处理、解释方法以及相关模块的研究中取得了丰硕的成果，使多分量地展勘探的理论基础与方法储备相对成熟，并已逐步应用于生产科研实践之中。如今多分量技术以及与这一技术紧密相连的各向异性研究已成为国内外地震勘探领域的研究热点之一。     

基于矢量波场分离的TI介质逆时偏移

基于两步法分离各向异性矢量波波场,第一步,将各向异性波动方程进行相似变换(使其具有明确直观的运动学和动力学特征),使其投影在各向同性方向上;第二步,各向异性介质传播算子波场分离基础上的波形校正,将投影于各向同性方向上的波场校正回各向异性方向上,最终达到各向异性波场分离的结果。笔者首先对VTI介质进行试算,以证明其可行性;此外,将地表数据进行分解,即所采集到的多分量地震数据在进行偏移成像之前先进行数据分解,得到纯净的q P波数据、q SV波数据以及q SH波数据,通过地表数据的分解将成像过程变成一个可控过程,通过对地表数据输入的控制得到我们所希望的成像结果分量,可以减少无谓的计算;对Hess模型正演炮记录进行了数据分解,并对其进行了逆时偏移成像以验证理论的可行性。     

基于地球物理模型实验的波场特征

采用理论分析和物理模拟相结合的方法对地震剖面中的波场成份进行了综合研究,波动理论研究表明,地震剖面含有多种波场信息成份,组成了一个各种成份各具变化特征的复合波场,这种复合波场含有P波和PS波成份等。在物理模型中,采用了较先进的实验系统,设计了砂泥岩组成的三层地层模型,(20-280-1220)观测系统,采样率为0.25ms。实验得到了三层地层模型的地震剖面,对所获得的地震剖面进行了波场特征分析,实验地震剖面中含有多种波场成份(P波、PS波和面波等)。波场理论研究结果得到物理模型实验的证实,表明地震剖面属复合波场剖面。这种叠后地震剖面可直接用于进行叠后弹性参数反演等以挖掘更多的有效地质信息,提高勘探效果,扩大地震剖面的应用范围。     

不同方位各向异性反演技术对比和总结

随着“两宽一高”地震采集技术的发展,基于方位各向异性理论的叠前P波裂缝反演技术的应用也越来越多。方位各向异性反演可以得到裂缝方位和裂缝强度,但是不同的反演技术得到的表征裂缝强度的参数各不相同,反演结果也常常有所差异,因此就造成了裂缝各向异性反演结果的不唯一性,进而造成谁才是“正确的”这种困惑和疑问。本文从Thomsen各向异性理论出发,通过裂缝模型(Hudson薄币模型、Schoenberg线性滑动模型)之间的相互关系,在不同的裂缝反演技术(VVAZ、Ruger近似和傅立叶级数)中建立各向异性的参数联系,给出了不同方位各向异性裂缝反演结果的真实含义和数学表达,并对不同反演技术与裂缝模型参数之间的联系进行了总结,进一步深化了方位各向异性裂缝反演的研究,为基于“两宽一高”数据开展大规模的裂缝检测奠定坚实的理论和技术基础。     

各向异性介质中的浅海海洋可控源电磁响应特征

由于受到空气波的影响,浅海海洋可控源电磁数据对海底储油层的反映较弱,如何对浅海数据进行处理和解释一直是海洋电磁理论研究的热点。随着近年来海洋电磁理论的不断完善,浅海数据已经可以被较好地处理与反演,但是其解释水平仍然受基本理论研究不足的制约。针对这一现状,本文开展了海底电各向异性对浅海数据影响规律的研究。具体方法为:利用欧拉旋转建立不同的海底电性各向异性模型,然后采用交错网格有限差分法计算浅海海洋可控源电磁响应,最后通过分析同线情况下电场E_x分量的振幅和相位曲线特征以及海底电场及电流密度分布规律,分析各向异性对浅海海洋可控源电磁响应影响的物理机制,并讨论浅海各向异性情况下海洋电磁对高阻储油层的识别能力。得出的结论为各向异性介质中的浅海海洋电磁响应特征与深海有较大区别,在进行数据的处理、反演和解释时应区别于深海情况。     

金属矿转换波地震勘查技术模拟

结合金属矿体地震地质数学模型,对多波多分量地震勘探的数据采集和资料处理方法进行了探讨和研究,主要针对多波资料的分离、去噪、共转换点道集选排、动校叠加、偏移等特殊技术进行了处理试验。在无法得到有效反射纵波资料的地区,可尝试采用转换波地震勘探方法技术;也可利用多波多分量地震勘探分析纵、横波速度以获得较多的岩性参数,降低多解性。模拟研究结果对今后开展金属矿转换波地震勘探方法技术的应用与研究有一定的借鉴作用。     

各向异性介质储层数值模拟及波场特征研究

各向异性介质储层中波场特征的研究,有利于对多波资料的准确解释。在弹性波方程基础上,结合数值模拟技术与AVO技术,对多种介质模型和第二类含气砂岩储层模型进行数值模拟与波场特征描述。以表征介质各向异性程度的Thomsen参数为出发点,研究各参数对地震波场动力学和运动学特征的影响,并对第二类含气砂岩介质中模拟得到的正演记录,以及各向异性参数对波场的影响程度进行分析,进一步加深了对该类储层各向异性特征的认识,这为各向异性介质中的参数反演与地震资料解释提供了有力的参考依据。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Late Wuchiapingian (Late Dzhulfian,early Late Permian) limestone olistolites within the Tertiary flysch of Glypia Unit (Mount Parnon,central–eastern Peloponnesus,Greece)

Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931.     

PALEONTOLOGY

正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.)     

GEOCHEMICAL EXPLORATION

正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.)     

MICROPALAEONTOLOGY

正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.)     

PETROLOGY

正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus.,     

ENVIRONMENTAL GEOLOGY

正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an     

PROSPECTING EXPLORATION

正20141266Fan Chaoyan(Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes,Guangzhou 510275,China);Wang Zhenghai On Error Analysis and Correction Method of Measured Strata Section with Wire Projection Method(Journal of