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Development of a System for 3D High-resolution Seismic Reflection Profiling on Lakes 总被引:2,自引:0,他引:2
A high-resolution three-dimensional (3D) seismic reflection system for small-scale targets in lacustrine settings has been
developed. Its main characteristics include navigation and shot-triggering software that fires the seismic source at regular
distance intervals (max. error of 0.25 m) with real-time control on navigation using differential GPS (Global Positioning
System). Receiver positions are accurately calculated (error<0.20 m) with the aid of GPS antennas attached to the end of each
of three 24-channel streamers. Two telescopic booms hold the streamers at a distance of 7.5 m from each other. With a receiver
spacing of 2.5 m, the bin dimension is 1.25 m in inline and 3.75 m in crossline direction. To test the system, we conducted
a 3D survey of about 1 km2 in Lake Geneva, Switzerland, over a complex fault zone. A 5-m shot spacing resulted in a nominal fold of 6. A double-chamber
bubble-cancelling 15/15 in3 air gun (40–650 Hz) operated at 80 bars and 1 m depth gave a signal penetration of 300 m below water bottom and a best vertical
resolution of 1.1 m. Processing followed a conventional scheme, but had to be adapted to the high sampling rates, and our
unconventional navigation data needed conversion to industry standards. The high-quality data enabled us to construct maps
of seismic horizons and fault surfaces in three dimensions. The system proves to be well adapted to investigate complex structures
by providing non-aliased images of reflectors with dips up to 30°. 相似文献
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Chirp frequency-modulated (FM) systems offer deterministic, repeatable source-signatures for high-resolution, normal incidence marine seismic reflection data acquisition. An optimal processing sequence for uncorrelated Chirp data is presented to demonstrate the applicability of some conventional seismic reflection algorithms to high-resolution data sets, and to emphasise the importance of a known source-signature. An improvement of greater than 60dB in the signal- to-noise ratio is realised from correlating the FM reflection data with the transmitted pulse. Interpretability of ringy deconvolved data is enhanced by the calculation of instantaneous amplitudes. The signal-to-noise ratio and lateral reflector continuity are both improved by the application of predictive filters whose effectiveness are aided by the repeatability of the Chirp source. 相似文献
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常规三维地震资料处理是以寻找深层油气为主要目标而设计的流程,在利用三维地震资料进行浅层地质条件评价和地质灾害评估时,需要针对浅部目标层进行高分辨率处理方法的研究。通过处理试验,发现影响浅层分辨率的处理参数与深层不同,从而确定了浅层处理中的最优参数;通过对琼东南盆地1 248 km2的三维地震数据利用不同偏移距进行处理,形成了3种地震数据体。通过对3种数据体的分析比较及综合考虑分辨率与信噪比后,选用偏移距250~1 650 m的数据体进行解释研究,确定浅层地质条件,评估潜在的地质灾害。 相似文献
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利用三维地震资料评估深水井位工程地质灾害 总被引:2,自引:0,他引:2
随着深水油气勘探开发的快速发展,因地质灾害而发生的石油钻井事故也不断增加。据统计深水钻井大约30%的花费用于解决安全事故,其中大部分用于因地质灾害而引起的安全事故。在钻探之前通过对设计井位进行井场及钻井工程地质灾害评估,找出潜在的危害钻井安全的地质因素,可以在很大程度上避免这类事故的发生。采用以油气勘探为目的的三维地震数据,经二维高分辨率处理,对尼日尔三角洲井场区及钻井过程中可能引起的工程地质灾害因素进行评估,这些因素包括海底滑坡、浅部断层、浅层气、天然气水合物、浅层高压水流、古河谷、泥穿刺与泥火山、异常高压等。研究结果表明,采用三维地震数据经二维高分辨率处理,可得到较为丰富的地质信息,可以满足深水井位对工程地质灾害评估的要求。 相似文献
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针对Q区块侏罗系延安组构造岩性油气藏呈现的河道窄、各向异性强,单单靠井控难以刻画砂岩的展布特征和难以描述低幅度构造的勘探难题。利用三维地震具有良好的横向分辨率、连续性的优势,采用精细层位标定与速度分析、反射结构特征识别和反演等方法,完成了对构造、断裂、储层等成藏因素的精细预测,为井位部署提供有力的技术支撑。 相似文献
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Tine Missiaen 《Marine Geophysical Researches》2005,26(2-4):145-155
The design of very high resolution (VHR) 3D marine surveys not only depends on the theoretical considerations of seismic imaging,
but is also dictated by the field conditions and the available budget. The main geophysical controlling factors include the
depth and dip of the target, and horizontal and vertical resolution. Working in shallow water environments and at high frequencies
will imply constraints on sampling, array directivity and positioning accuracy. In this paper we describe the main requirements
and constraints involved in VHR 3D acquisition. The second part of the paper focuses on the flexible acquisition system “Opus3D”
recently developed for shallow water investigations. The system provides improvements in imaging resolution in a relatively
simple and cost-effective way. Acquisition and positioning constraints limit the system to nearshore studies. The experience
gained from various surveys with this new acquisition system allow us to formulate a number of practical specifications and
guidelines for 3D survey design in shallow water. 相似文献
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受大深度水体的影响,传统的海面拖曳式多道地震技术在进行深水地层探测时,目标地层深度处的菲涅耳半径非常大,水平分辨率低,难以满足海域天然气水合物高精度探测需求。针对海面拖曳式地震探测技术存在的上述问题,设计了一套可以在2 000 m水深近海底作业的地震探测系统。应用耐压透声发射阵技术,克服了20 MPa外压环境和瞬时内压冲击对等离子体震源子波幅频特性的不利影响,研制的深拖等离子体震源的声源级达到214 dB,主频低于1 000 Hz;水下控制中心采用集成SoC片上系统设计,可以对震源进行定距激发控制,进行近海底多道地震数据的连续采集。系统在2019年深海试验拖曳最大深度达2 025 m,测试剖面数据显示最大地层穿透深度达380 m,纵向分辨率<2 m,横向分辨率<10 m,为深水海域沉积地层的深拖高分辨率地震探测提供了技术支撑。 相似文献
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在海洋地震资料处理中,由于检波点空间分布不均匀造成的采集脚印现象会影响地震资料成像,特别是对双源单缆方式采集的三维地震数据影响更为明显。通过对海上某区双源单缆方式采集的天然气水合物三维地震数据采集脚印形成原因及特点的详细分析,最终分别在叠前采用子波处理、潮汐、水速校正、面元中心化方法,叠后采用频率、波数域滤波的方法压制采集脚印。通过以上关键技术的应用,提高了双源单缆方式采集的三维地震数据的信噪比和分辨率,采集脚印从时间切片和剖面上均有了明显衰减,而且实现了最大限度的保持振幅、频率、相位属性。为精细刻画、描述地质构造形态和预测天然气水合物储层分布及有利富集区带,提供可靠的地震资料。 相似文献
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Very high-frequency marine multichannel seismic reflection data generated by small-volume air- or waterguns allow detailed, high-resolution studies of sedimentary structures of the order of one to few metres wavelength. The high-frequency content, however, requires (1) a very exact knowledge of the source and receiver positions, and (2) the development of data processing methods which take this exact geometry into account. Static corrections are crucial for the quality of very high-frequency stacked data because static shifts caused by variations of the source and streamer depths are of the order of half to one dominant wavelength, so that they can lead to destructive interference during stacking of CDP sorted traces. As common surface-consistent residual static correction methods developed for land seismic data require fixed shot and receiver locations two simple and fast techniques have been developed for marine seismic data with moving sources and receivers to correct such static shifts. The first method – called CDP static correction method – is based on a simultaneous recording of Parasound sediment echosounder and multichannel seismic reflection data. It compares the depth information derived from the first arrivals of both data sets to calculate static correction time shifts for each seismic channel relative to the Parasound water depths. The second method – called average static correction method – utilises the fact that the streamer depth is mainly controlled by bird units, which keep the streamer in a predefined depth at certain increments but do not prevent the streamer from being slightly buoyant in-between. In case of calm weather conditions these streamer bendings mainly contribute to the overall static time shifts, whereas depth variations of the source are negligible. Hence, mean static correction time shifts are calculated for each channel by averaging the depth values determined at each geophone group position for several subsequent shots. Application of both methods to data of a high-resolution seismic survey of channel-levee systems on the Bengal Fan shows that the quality of the stacked section can be improved significantly compared to stacking results achieved without preceding static corrections. The optimised records show sedimentary features in great detail, that are not visible without static corrections. Limitations only result from the sea floor topography. The CDP static correction method generally provides more coherent reflections than the average static correction method but can only be applied in areas with rather flat sea floor, where no diffraction hyperbolae occur. In contrast, the average static correction method can also be used in regions with rough morphology, but the coherency of reflections is slightly reduced compared to the results of the CDP static correction method. 相似文献
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Carl Jörg Petersen Stefan Bünz Steinar Hustoft Jürgen Mienert Dirk Klaeschen 《Marine and Petroleum Geology》2010
The newly developed P-Cable 3D seismic system allows for high-resolution seismic imaging to characterize upper geosphere geological features focusing on geofluid expressions (gas chimneys), shallow gas and gas hydrate reservoirs. Seismic imaging of a geofluid system of an Arctic sediment drift at the Vestnesa Ridge, offshore western Svalbard, provides significantly improved details of internal chimney structures from the seafloor to ∼500 m bsf (below seafloor). The chimneys connect to pockmarks at the seafloor and indicate focused fluid flow through gas hydrated sediments. The pockmarks are not buried and align at the ridge-crest pointing to recent, topography-controlled fluid discharge. Chimneys are fuelled by sources beneath the base of gas hydrate stability zone (GHSZ) that is evident at ∼160–170 m bsf as indicated by a bottom-simulating reflector (BSR). Conduit centres that are not vertically straight but shift laterally by up to 200 m as well as discontinuous internal chimney reflections indicate heterogeneous hydraulic fracturing of the sediments. Episodically active, pressure-driven focused fluid flow could explain the hydro-fracturing processes that control the plumbing system and lead to extensive pockmark formation at crest of the Vestnesa Ridge. High-amplitude anomalies in the upper 50 m of the chimney structures suggest formations of near-surface gas hydrates and/or authigenic carbonate precipitation. Acoustic anomalies, expressed as high amplitudes and amplitude blanking, are irregularly distributed throughout the deeper parts of the chimneys and provide evidence for the variability of hydrate and/or carbonate formation in space and time. 相似文献
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番禺4洼新近系NWW—SEE向正断层非常发育,这些断层上升盘的构造圈闭是重要的勘探目标。但由于一次三维地震资料采集方向与断层平行,断层附近阴影现象非常严重,表现为信噪比低、同相轴不合理的“下拉”和扭曲畸变的“假象”,严重影响断层上升盘的精细构造落实。为此,实施了垂直于断层方向的二次三维地震采集,使得断层阴影带成像比一次三维有较大改善。为了更好地解决断层阴影带成像难题,针对方位各向异性,对2次采集的三维资料进行了以双方位各向异性叠前深度偏移(PSDM)为核心的双方位融合处理。2个方位各自处理成果和双方位融合处理结果对比表明:对于断层阴影带成像,垂直断层方向采集的三维明显优于平行断层方向采集的三维;而结合2次采集的双方位融合处理资料效果最好:既能有效的消除断层阴影带成像畸变,又能提高信噪比。经研究区油田评价井在断层阴影带的钻探结果证实了双方位融合处理结果的可靠性,同时,可为类似地区解决断层阴影带成像难题提供采集设计和处理技术等方面的借鉴。 相似文献
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通常情况下 Wire- frame(线框图 )不能唯一描述 3D object。本文给出 1种基于 Wire- frame的 3D object重构求解算法。该算法获得唯一解时 ,则表明 Wire- frame对应唯一的 3D object;多个解时 ,则给出所有的可行解 相似文献