共查询到20条相似文献，搜索用时 301 毫秒
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2008年5月12日汶川发生里氏8.0级地震的发震机制与龙门山断裂带的构造特征紧密相关,应用反射地震探测方法精细探测发震构造内部的结构特征,对研究汶川地震的发震机理有重要意义.5.12地震后在地表错断最剧烈的区域之一虹口乡白庙村穿过发震构造和深钻科研井WSFD-1和WSFD-2布置了兼顾浅中深层信息的反射地震探测剖面,该区域断裂带硬岩出露,地形地貌复杂多变,起伏剧烈,只能采取弯线地震测线布设方式采集二维反射地震数据,而且弯曲度大,造成CDP点分散严重.区域内构造复杂,褶皱逆推构造发育,地层和构造倾角大,采用常规二维地震数据处理方法进行叠加处理时,易将不同地层的反射信息叠加到同一反射层.弯线叠加剖面上侧面波,混波干扰严重,会显著地降低原本低信噪比数据的分辨率,或剖面可靠性低,容易在二维剖面中造成解释陷阱.本文利用弯线地震采集的三维特性,用拟三维地震叠加技术处理汶川地震科学钻井附近横跨北川-映秀断裂带的二维弯线地震数据,弥补常规二维弯线地震数据处理技术的不足,将不同地层的反射信息分离归位到不同的三维叠加剖面上,解决二维弯线地震数据处理时混波干扰严重的难题.通过理论分析和实验选取合适的共中心点面元,获得了高分辨率的三维叠加剖面.相比于二维弯线叠加剖面,三维叠加剖面切片成像更真实,剔除了不同地层反射信息混叠的影响,能得到更准确的断点信息,并可以获得沿断层走向横向的信息,显著提高了构造解释的可靠性和精度.应用拟三维地震数据处理方法处理龙门山断裂带的二维弯线地震数据,获取高分辨率的构造信息,有利于断裂带内汶川地震发震机制和龙门山隆起机制的解释. 相似文献
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Heather Schijns Suvi Heinonen Douglas R. Schmitt Pekka Heikkinen Ilmo T. Kukkonen 《Geophysical Prospecting》2009,57(6):997-1008
A traveltime inversion technique is applied to model the upper ∼40 m of the subsurface of a glaciated shield rock area in order to calculate static corrections for a multi-azimuth multi-depth walk-away vertical seismic profile and a surface seismic reflection profile. First break information from a seismic refraction survey is used in conjunction with a ray-tracing program and an iterative damped least-squares inversion algorithm to create a two-dimensional model of the subsurface. The layout of the seismic survey required crooked seismic lines and substantial gaps in the source and receiver coverage to be accounted for. Additionally, there is substantial topographical variation and a complex geology consisting of glaciofluvial sediment and glacial till overlying a crystalline bedrock. The resolution and reliability of the models is measured through a parameter perturbation technique, normalized χ2 values, root means square traveltime residuals and comparison to known geology. 相似文献
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一般而言,由于地下非均质体的存在所产生的二次波源,由它再生成新的波场,叫散射波场。目前,将散射波作为有效波来成像,已开始在溶洞和裂缝等特殊地质体的识别中得到应用。但对于野外资料采集来说,地表复杂地区,如戈壁、砾石区和山前带,大量存在的散射波却是干扰波,它们的存在会严重影响资料的品质,而其研究与实际应用国内外还很少。因此,通过正演模拟,分析散射波的基本特征,在此基础上研究散射波的去噪方法显得十分必要。本文从地震波运动学时距关系出发,研究了反射波和散射波的几何特征;然后用有限差分正演,模拟了散射波场,用理论模型研究并测试了局域双曲线Radon变换散射波去噪新方法。对于实际炮集资料,分析了F-K滤波方法压制散射噪声的局限,采用局域双曲Radon变换有效地去除了炮集中存在的散射噪声,取得了较好的应用效果。 相似文献
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Cachar area, a part of the Assam–Arakan frontal fold belt in the eastern part of India is characterized by a series of narrow anticlines which are dissected by a number of faults including thrusts, and broad synclines. Out of several exposed structures, Badarpur anticline is most important because of its major share of hydrocarbon strikes in Cachar. However, the seismic image of this area so far has been extremely poor for deciding locations for exploratory drilling. The problems in obtaining a good seismic image in this area include proper spread configuration including far and near offsets to capture reflected signals from the complex subsurface, variation of charge-sizes and depths along a line, large variation in statics due to rapid changes in elevation and near surface properties. The presence of coherent noise due to scattering and proper migration are major processing problems. This paper deals with the problem of spread configuration. For areas of complex subsurface, spread configuration obtained through field experiment at one spot may be quite different from other spots, requiring a large number of costly experiments. In this work, therefore, we used numerical modeling to derive an optimum spread configuration. For this, we chose a line passing through four wells on Badarpur anticline, and prepared a depth model using available seismic, surface geological and well data. Continuous synthetic common shot records were generated through oblique incidence ray tracing and were processed to obtain stacks with various spread configurations. Comparison of these stacks of synthetic data shows that end-on shooting configuration is inadequate for acquiring a good seismic image of the complex subsurface. From the present study it is evident that a split–spread configuration with near and far offsets of 50 m and 2400 m, respectively, can bring out optimum seismic images in Badarpur and other anticlines in this area. 相似文献
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Saeid Cheraghi Mostafa Naghizadeh David Snyder Rasmus Haugaard Thomas Gemmell 《Geophysical Prospecting》2020,68(1):62-81
In 2017, the Metal Earth multi-disciplinary exploration project acquired a total of 921 km of regional deep seismic reflection profiles and 184 km of high-resolution seismic reflection profiles in the Abitibi and Wabigoon greenstone belts of the Superior province of Canada. The Abitibi belt hosts several world-class mineral deposits, whereas the Wabigoon has sparse economic mineral deposits. Two high-resolution surveys in the Swayze area, a poorly endowed part of the western Abitibi greenstone belt, served as pioneer surveys with which to better understand subsurface geology and design a strategy to process other surveys in the near future. Swayze seismic data were acquired with crooked survey geometries along roads. Designing an effective seismic processing flow to address these geometries and complex geology required straight common midpoint lines along which both two-dimensional prestack dip-moveout correction and poststack migration processing were applied. The resulting seismic sections revealed steeply dipping and subhorizontal reflections; some correlate with folded surface rocks. An interpreted fault/deformation zone imaged in Swayze north would be a target for metal endowment if it extends the Porcupine–Destor structure. Because of the crooked line geometry of the surveys, two-dimensional /three-dimensional prestack time migration and swath three-dimensional processing were tested. The prestack time migration algorithm confirmed reflections at the interpreted base of the Abitibi greenstone belt. The swath three-dimensional images provided additional spatial details about the geometries of some reflections, but also had less resolution and did not detect many reflectors observed in two dimensions. Geological contacts between felsic, mafic and ultramafic greenstone rock layers are thought the main cause of reflectivity in the Swayze area. 相似文献
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Geostatistical seismic inversion for non‐stationary patterns using direct sequential simulation and co‐simulation 
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下载免费PDF全文 Hamid Sabeti Ali Moradzadeh Faramarz Doulati Ardejani Leonardo Azevedo Amilcar Soares Pedro Pereira Ruben Nunes 《Geophysical Prospecting》2017,65(Z1):25-48
Geostatistical seismic inversion methods are routinely used in reservoir characterisation studies because of their potential to infer the spatial distribution of the petro‐elastic properties of interest (e.g., density, elastic, and acoustic impedance) along with the associated spatial uncertainty. Within the geostatistical seismic inversion framework, the retrieved inverse elastic models are conditioned by a global probability distribution function and a global spatial continuity model as estimated from the available well‐log data for the entire inversion grid. However, the spatial distribution of the real subsurface elastic properties is complex, heterogeneous, and, in many cases, non‐stationary since they directly depend on the subsurface geology, i.e., the spatial distribution of the facies of interest. In these complex geological settings, the application of a single distribution function and a spatial continuity model is not enough to properly model the natural variability of the elastic properties of interest. In this study, we propose a three‐dimensional geostatistical inversion technique that is able to incorporate the reservoir's heterogeneities. This method uses a traditional geostatistical seismic inversion conditioned by local multi‐distribution functions and spatial continuity models under non‐stationary conditions. The procedure of the proposed methodology is based on a zonation criterion along the vertical direction of the reservoir grid. Each zone can be defined by conventional seismic interpretation, with the identification of the main seismic units and significant variations of seismic amplitudes. The proposed method was applied to a highly non‐stationary synthetic seismic dataset with different levels of noise. The results of this work clearly show the advantages of the proposed method against conventional geostatistical seismic inversion procedures. It is important to highlight the impact of this technique in terms of higher convergence between real and inverted reflection seismic data and the more realistic approximation towards the real subsurface geology comparing with traditional techniques. 相似文献
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复杂地表的单程波动方程地震叠前正演 总被引：4，自引：0，他引：4
作者基于数学检波器和等时叠加原理,实现了复杂地表的单程波动方程地震叠前正演模拟。该方法采用虚拟的数学检波器接收地下的反射地震信号,灵活地将接收点布置在地表的任何地方,从而满足地表起伏的要求。此外,根据等时叠加原理, 该方法采用单程波动方程进行波场延拓和成像,计算简单快速。通过复杂正断层的数值模拟,得到了高信噪比的共炮集地震记录,并采用适用于起伏地形的深度偏移方法对该共炮集地震记录进行了叠前深度偏移,较好地实现了地震波的偏移归位,从而证明了这里提出的起伏地表的单程波动方程地震叠前正演方法是正确和有效的。 相似文献
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浅层地震资料解释陷阱(英文) 总被引：1，自引：0，他引：1
高分辨率浅层地震方法是在近地表调查中使用最为广泛的方法。然而,在许多情况下,地震资料的解释经常会出现错误。在本文中,我们介绍了三个例子,分析了造成P波,SH波,多道的面波(MASW)地震资料解释的错误原因,大都是由于在表面或地下条件约束不确当引起的。第一个例子是P波反射剖面上的一个波的特征被解释为浅层断裂带,但后来证实它是由高水平的背景噪音引起的,因为采集测线通过了一个公路交叉口。第二个例子是SH波反射地震剖面上一个波特征被解释为是逆倾向滑断层,但有针对性的钻探表明,它是一个侵入到基岩面的一个深层局部侵蚀。最后,第三个例子,MASW调查剖面上,一个陡倾特征一开始被解释为基岩谷。然而,后来的钻探表明这是一个非常软的湖泊沉积物,后者严重损坏了应用面波频段。虽然最初的解释是不正确的,但这刺激地球物理学家和地质学家之间的讨论,并强调地球物理数据采集的时候,采集之前以及采集之后需要科学家之间有意义的合作与讨论。 相似文献
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控制照明与面向目标成像的观测系统设计 总被引：1，自引：0，他引：1
Liu Shouwei Geng Jianhua Feng Wei 《应用地球物理》2005,2(4):230-234
常规地震观测系统设计方法基于地下水平层 状介质的假设,通常不能适应复杂构造情况。我们 从控制照明的思想出发,提出了一种面向目标成像 的地震观测系统设计方法,该方法需要一个由初步 地震解释得到的速度模型。利用单程傅立叶有限差 分波场传播算子将目标层的平面源延拓到地表,通 过分析从目标层延拓到地表的波场能量的分布,可 以确定目标层成像所需要的炮点或者检波点的位置。 利用SEG-EAGE盐丘模型数值试算结果表明,该方法 用于设计面向目标成像的特定地震采集系统。 相似文献
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Seismic imaging quality is critical to describing reservoirs. There are many methods that can improve imaging quality; some rely on advanced processing means, whereas others rely on changing the field acquisition methods. However, most of the acquisition methods focus on improving imaging by using infill shots without considering the target-layer illumination energy. Moreover, total infill shooting greatly increases the acquisition cost. In this paper, we present a new method for maximizing the contribution to the target shadow area illumination by automatic local infill shooting. Thus, we designed 2D and 3D models and obtained the depth migration section by forward modeling, infill shots, depth migration, etc. The model results also show that by choosing the most appropriate number of shot points, we can enhance the shadow area energy and improve the target-layer imaging quality at low cost. 相似文献
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Optimal filtering high-resolution seismic reflection data using a weighted-mode empirical mode decomposition operator 总被引：2，自引：0，他引：2
Leonardo Macelloni Bradley Matthew Battista Camelia Cristina Knapp 《Journal of Applied Geophysics》2011,75(4):603-614
Gas-hydrate related processes in deep-water marine settings exist on spatial scales that challenge conventional seismic reflection profiling to successfully image them. The conventional approach to acoustic identification of buried hydrates is to use advanced, cost-prohibitive survey techniques and highly customized software to define subsurface structure wherein compositional changes may be modeled and/or interpreted. This study adopts a different approach derived from recent theoretical advancements in signal processing. The method consists in optimal filtering high resolution, single-channel seismic reflection data using the Empirical Mode Decomposition (EMD). The time series is decomposed in sub-components and the noisy portions are suppressed adopting the technique that we referred as Weighted Mode(s) EMD. The optimal filtering greatly improves the resolution and fidelity of the seismic data set.High Resolution single channel seismic profiles, acquired over a carbonate\hydrates site in the northern Gulf of Mexico, manipulated in such way, show a complex, shallow subsurface, and suggest potential evidence for buried gas hydrates. 相似文献
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受井中检波器串级数局限,垂直地震剖面(VSP)反射波成像范围窄,且不能对井中最浅接收点上方区域有效成像.虽然多次波成像能扩大成像范围,但在实际应用中尚有诸多困难和挑战.本文根据Wapenaar的地震干涉理论,基于上下行波场分离技术,研发了VSP地震干涉成像方法.该方法将VSP自由表面多次波重建为在地表震源位置激发(虚震源)接收的拟地面地震反射波,然后偏移成像,以达到对多次波间接成像的目的.通过数值模型实验,测试了VSP干涉成像的极限分辨率,并讨论了主要采集参数的影响,结果表明:该方法的垂向和水平极限分辨率分别达约10m和20m,且能分辨深度达6500m处的50m×100m溶洞;采用12至24道井中检波器串采集的VSP资料,其干涉成像结果显著优于VSP反射波成像,与相应的地面地震成像效果相当.将本文方法应用于新疆地区采集的VSP资料,结果表明:与VSP反射波成像相比,成像同相轴更加连续,成像范围显著扩大;与地面地震成像相比,成像结果相当,尤其在浅中部甚至更好.新方法不仅无需进行井中接收点静校正,且能显著增大成像范围,有利于成像同相轴的追踪对比、地震属性提取和地质解释,尤其对中国新疆地区深部缝洞型储层的成像,具有广泛的实际应用前景. 相似文献
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The directional effect of shaped charge is a well-known feature used for a long time in military weapons, oil well guns, and steel industry. This charge was successfully applied as a seismic energy source by Petrobrás during the past three years under different surface and geological conditions. Preliminary amplitude measurements taken with fixed gain shallow refraction instruments showed a consistent difference between conventional and shaped charges. Lately, a similar difference has been noted in deep reflection energy recorded with digital binary gain instruments as well as in deep oil well velocity surveys. Direct comparisons along more than 50 km of multiple coverage field reflection shooting are in agreement with these results and have proved the practical advantage of this source as compared to conventional dynamite. This source has been used since 1971 in routine seismic operation in the Amazon jungle with 300 gram unit charges distributed in small and large shot arrays increasing substantially the coverage and halving the cost at a higher record quality. A large amount of production seismic field work has been carried out in several other areas attesting the successful application of the shaped charges. 相似文献
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复杂地表探区,尤其是盆山过渡区的油气勘探是我国也是世界上油气勘探的重点区域,但是此类区域油气地震勘探中满足精确地震成像的速度建模一直是个没有很好解决的问题.本文提出了一种综合性的数据域初至波走时与成像域反射波走时联合层析复杂地表浅中深层速度建模方法,并针对联合层析速度反演解的非唯一性问题,深入地分析了层析反演中正则化的本质意义,指出了建立构造特征正则化方法的具体技术路线,提出了联合层析的实现流程及策略.理论和实际数据试验表明,本文提出的数据域初至走时与成像域反射走时联合层析浅中深层速度建模技术避免了常规建模方法中浅层速度模型与中深层速度模型的融合问题,较好地解决了传统成像域反射层析对近地表模型的不可控更新问题,整体提升了深度域浅中深层速度模型的建模精度,进而提高了复杂地表、复杂构造区的地震成像质量. 相似文献
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正演模拟技术在地震采集设计中的应用 总被引：1，自引：0，他引：1
随着地震勘探开发的不断深入和发展,地震勘探的主战场逐渐向复杂地区转移.复杂地区既指地表条件复杂的地区,也指地下地质构造和地层条件复杂的地区,这些都对地震勘探提出了新的挑战和更高的要求.地震正演模拟正是开展此类问题研究的一个重要手段和方法.目前市场上具有正演模拟功能的软件大多是根据射线理论采用射线追踪的方法来完成正演模拟的,这种方法不能很好地反映地震波的动力学特征,特别是在复杂地区难以得到正确的结果.本文利用高阶有限差分有效克服了常规有限差分算法求解波动方程的频散问题,并以高效的OpenMP并行计算模式进行了并行优化,较大程度上提高了正演计算的速度和精度;同时实现了二阶Higdon边界条件,改善了边界吸收效果;也在一定程度上提高了计算速度.塔中地区主要目的层埋藏深,逆断层发育,地震反射特征复杂,增加了地震勘探的难度.本文依据该地区的地质模型,利用波动方程正演技术论证了该地区的地震采集观测系统,为该区地震采集观测系统的设计提供了科学依据. 相似文献