海洋工程高分辨反射地震勘探的震源技术特征

文中首先简要的回顾了海洋高分辨地震勘探反射技术的基础理论，介绍了海洋工程勘探中主要使用的四大类高分辨地震震源一受控波束类震源（声纳）、加速水团技术类震源、挤压震源、爆炸式震源，并对各类震源技术的技术特点进行了对比分析，指出了这些技术发展方向、使用范围和应用前景。     

秘鲁近海气体水合物带底界的地震反射特征分析

位于秘鲁近海的ODP第688站位的地震资料显示出：该区存留有似海底反射层（简称BSR）,其深度与气体水合物稳定的深度相当。虽然在太平洋和大西洋的科学钻探岩芯中已经发现了气体水合物,但通常在有BSR显示地区避免钻探,这是因为钻探容易引起含水合物的沉积物民封闭的游离气的释放,造成危险。利用反褶积和真振幅恢复技术,可对地震资料重新处理,达到对BSR定量分析。从而地震资料提取声波参数,从第688站位的钻孔测量物性资料,利用前述两项资料可合成地震记录,并同实际地震资料进行比较,来估算游离气带的厚度。结果显示出：BSR沿侧向呈不连续分布,在BSR表现为强振幅的地带,其下游离气带厚5．5－17m;在BSR呈弱振幅之处,游离气带厚度不足5．5m,甚至完全缺失。     

生物礁的地震鉴别方法

在海区生物礁的勘探具有广阔的前景。本文以南海新生代盆地大量的地震资料为基础,阐述了生物礁在地震剖面上的各种反映特征和鉴别生物礁的方法,尤其对如何在剖面上判别各类型的生物礁作了较细致的分析,同时指出在实际工作中要注意排除与生物礁的反射具有相似地震异常的其它地质体。     

海上地震虚反射相位剔除法反褶积

在分析了虚反射的形成机制及其滤波器频谱特性的基础上，提出了一种在频率域剔除地震鬼波的新方法，该方法直接剔除的是虚反射滤波器相位谱的影响，而对于振幅谱，则是通过同时消除虚反射与地震子波两者共同的影响来拓宽地震记录的有效频谱，处理过程自动避免了鬼波滤波器的“零值点”问题，其最终结果是以获取反射生活费数为期望输出，因此，该方法在消除鬼波的同时可进一步提高地震剖而后 分辨率。实验表明，本文所提出的反褶积方法具有较好的容噪能力。且在鬼波延迟时以及虚反射界面反射系数存在一定误差的情况下仍能获得令人满意的处理结果。     

临南洼陷带滩坝砂岩储层分布

临南洼陷带沙四段滨浅湖滩坝相成因的砂体广泛发育,近年来已成为该区十分重要的勘探后备阵地。但该区火成岩发育,地震资料品质较差,滩坝砂的分布发育不清,不利于勘探部署。在深化研究沙四上亚段古地貌、沉积特征的基础上,运用频谱分解等技术提高地震资料分辩率,综合利用了正演及属性分析等技术,对滩坝砂岩的发育范围进行了预测,取得了良好的效果,为该层系油藏的勘探提供了可靠的依据。     

海底浅层圈闭与浅层气地震反射特征对比

海底浅层圈闭条件是决定浅层气反射特征的重要因素,根据海底浅层圈闭条件的分析、国内外浅层气分布区反射特征与底质类型对比分析和南黄海西部地区浅部断层分析,得出结论:(1)浅层气的圈闭条件主要受海底底质类型与浅部断层控制,常见圈闭类型为岩性圈闭和断层圈闭;(2)底质类型是决定浅层气反射特征的重要因素。分析认为海底表层沉积物的泥砂含量决定了圈闭中盖层封闭能力,进而决定了浅层气聚集能力和储集量,形成不同浅层气地震反射特征;(3)某些现代三角洲地区,受潮流或河流与海洋共同作用影响,表层底质经常与整个浅层的物质组成差别较大。由于其内部一般含有较厚的细颗粒黏土质粉砂和粉砂质黏土,封闭能力较强,可封闭较多浅层气,能形成大规模的声学空白反射,但常观察到浅层气反射顶界面局部突起呈旗舰状;(4)浅部断层既可形成断层圈闭,也可充当浅层气的运移通道。断层圈闭通常较少见且难以识别,浅部断层在第四纪松散地层中更多地充当了浅层气运移的通道;(5)浅部地层存在多套含泥较多的地层且形成圈闭时,浅层气被多次圈闭,会在不同深度形成"楼层式"的多个强反射界面、声学扰动。     

长江口外海域浅层气地震反射形态特征及分布

通过对长江口外海域浅层气地震反射特征的研究,发现该地区浅层气地震反射形态特征丰富,按不同形态特征分类如下:(1)按整体形态特征分为:幕状反射、柱状反射、气烟囱状反射;(2)按顶界面形态特征分为:不规则顶界面、较规则顶界面;(3)按侧面形态特征分为:侧面竖直、侧向突出;(4)按组合形态特征分为:垂向多层强反射、横向间断的浅层气反射、竖向变化的浅层气反射。总结了调查区内浅层气反射形态特征的分布规律,编制了长江口外海域浅层气分布图。讨论了浅层气反射区内部的强反射分布形态与浅层气空间运移路径的对应关系。     

地震资料亮点处理及特征分析

一、前言胜利油田地处我国东部渤海湾地区，油气资源十分丰富，地质条件和地表条件却十分复杂．经过近30年的勘探，证实了在东部20000多平方公里的范围内，各凹陷基本上形成了不同层系、不同类型，上下叠合连片的复会含油气区，但是探明的天然气储量，仅占油气总储量的4．3％，油气比例不协调．最近几年使用普通的地震方法，在陈家庄凸起、盐家、单家寺、广饶、垦东一青培子、呈岛凸起等地区，发现并圈定了几百个含气砂体的范围，在“七五”期间，采用亮点找气技术，取得了明显的经济效益和社会效益．为适应油气勘探的发展，改进以往的工作…     

海洋地震勘探中地震波、鬼波综合效应分析与应用

鬼波是影响海洋地震资料采集质量的重要因素之一,经过海水表面反射的鬼波与海底反射波相互叠加。“地震波、鬼波的综合效应”受很多因素的影响,文中从传播路径、传播时间等方面讨论了地震波与鬼波的综合效应。通过计算机模拟了二者的综合效应,与实测资料进行了对比,其幅频特性中陷波点、幅度等特性非常接近。结合水合物勘探的目的,文章探讨了基于识别BSR的勘探频率要求震源和电缆的最佳沉放深度,并通过实际应用验证了理论推算的正确性。     

Development of a System for 3D High-resolution Seismic Reflection Profiling on Lakes

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°.     

黄河口现代海洋沉积高分辨率地震地层学研究

本文运用地震地层学的知识,结合KDG2和S3钻孔资料,对2002年得到的现代黄河口地区的浅地层地震剖面进行了分析解释,共划分出中更新世以来11个地震地层单元,对每个地震地层单元进行了地震相的有关描述,对剖面上出现的地质现象给予了合理推测和详细分析,并结合相邻的钻孔资料,与全球冰期进行对比,构筑了黄河口地区晚第四纪以来地层的沉积模式。     

沧东凹陷沙河街组地震地层分析

利用地震资料及地质、钻井资料,对沧东凹陷沙河街组地震反射剖面进行了地震界面及地震层序划分,对其反射特征进行了较详细的描述。在进行地震相及沉积相划分和分析的基础上,对各层序的沉积特征进行了分析,这为该地区沉积盆地的油气生储盖特征提供了基础资料[1]。     

现代长江水下三角洲浅地层地震相特征

利用传统的地震相分析方法,分析总结现代长江水下三角洲浅地层地震剖面反射波的几何形态、内部反射结构、连续性、振幅等特征,形成对长江水下三角洲各典型地震相特征的认识,圈定相应的地震相范围,并结合钻孔资料,解释了长江口范围三角洲前积、浅海沉积、古河道等各沉积相的分布。结果表明,现代长江水下三角洲浅地层各地震相特征明显。典型的三角洲前积地震相主要分布在长江口外东北部,其余大部为典型浅海沉积地震相,且浅海地震相特征向口内逐渐变弱,表现为浅砂或淤泥型地震相,向口外逐渐有晚更新世基底地震相出露,并发育古河道地震相,此外,浅层气地震相嵌入区内各个地震相范围。     

Crustal Structures of the Northernmost South China Sea: Seismic Reflection and Gravity Modeling

The South China Sea (SCS) is a marginal sea off shore Southeast Asia. Based on magnetic study, oceanic crust has been suggested in the northernmost SCS. However, the crustal structure of the northernmost SCS was poorly known. To elaborate the crustal structures in the northernmost SCS and off southwest Taiwan, we have analyzed 20 multi-channel seismic profiles of the region. We have also performed gravity modeling to understand the Moho depth variation. The volcanic basement deepens southeastwards while the Moho depth shoals southeastwards. Except for the continental margin, the northernmost SCS can be divided into three tectonic regions: the disturbed and undisturbed oceanic crust (8–12 km thick) in the southwest, a trapped oceanic crust (8 km thick) between the Luzon-Ryukyu Transform Plate Boundary (LRTPB) and Formosa Canyon, and the area to the north of the Formosa Canyon which has the thickest sediments. Instead of faulting, the sediments across the LRTPB have only displayed differential subsidence offset of about 0.5–1 s in the northeast side, indicating that the LRTPB is no longer active. The gravity modeling has shown a relatively thin crust beneath the LRTPB, demonstrating the sheared zone character along the LRTPB. However, probably because of post-spreading volcanism, only the transtension-shearing phenomenon of volcanic basement in the northwest and southeast ends of the LRTPB can be observed. These two basement-fractured sites coincide with low gravity anomalies. Intensive erosion has prevailed over the whole channel of the Formosa Canyon.     

Seismic character of gas hydrates on the Southeastern U.S. continental margin

Gas hydrates are stable at relatively low temperature and high pressure conditions; thus large amounts of hydrates can exist in sediments within the upper several hundred meters below the sea floor. The existence of gas hydrates has been recognized and mapped mostly on the basis of high amplitude Bottom Simulating Reflections (BSRs) which indicate only that an acoustic contrast exists at the lower boundary of the region of gas hydrate stability. Other factors such as amplitude blanking and change in reflection characteristics in sediments where a BSR would be expected, which have not been investigated in detail, are also associated with hydrated sediments and potentially disclose more information about the nature of hydratecemented sediments and the amount of hydrate present.Our research effort has focused on a detailed analysis of multichannel seismic profiles in terms of reflection character, inferred distribution of free gas underneath the BSR, estimation of elastic parameters, and spatial variation of blanking. This study indicates that continuous-looking BSRs in seismic profiles are highly segmented in detail and that the free gas underneath the hydrated sediment probably occurs as patches of gas-filled sediment having variable thickness. We also present an elastic model for various types of sediments based on seismic inversion results. The BSR from sediments of high ratio of shear to compressional velocity, estimated as about 0.52, encased in sediments whose ratios are less than 0.35 is consistent with the interpretation of gasfilled sediments underneath hydrated sediments. This model contrasts with recent results in which the BSR is explained by increased concentrations of hydrate near the base of the hydrate stability field and no underlying free gas is required.     

浅海回填区域的地震映象效果分析

地震映象法是近期工程物探在工程地质与环境地质勘察中新出现的1种浅层地震探测方法。本文主要介绍该方法的实用方法技术与主要特点及其实际应用效果。并通过奥运工程勘察实例详细分析了该方法在复杂的浅海人工回填区域中不同的填入物与地质体在时间剖面上所展现的各种不同波形特征。     

西湖凹陷平北地区平湖组下段烃源岩分布地震预测

西湖凹陷平北地区现有钻井稀少且分布不均,采样分析资料缺乏,不同层段烃源岩非均质性极强,导致烃源岩分布特征尚不明确。针对上述难题,基于地化、测井、录井、地震等资料,运用地震相−沉积相−有机相转化法和地震速度−岩性分析法对西湖凹陷平北地区平湖组下段烃源岩有机相特征及厚度分布进行了研究,并对有利烃源岩的分布进行了预测。结果表明：① 平湖组下段烃源岩有机相可划分为潮控三角洲前缘A相、潮间带B相和局限海C相三种类型,其中平下上亚段潮控三角洲前缘A相最为发育,位于研究区的中部区域,而平下下亚段潮间带B相最为发育,主要位于研究区的西部区域;② 平下下亚段烃源岩具有东西分带、西薄东厚的特征,最大厚度可达500余米;而平下上亚段烃源岩总体上具有西北薄东南厚的特征,向东南方向厚度最高可达1000余米;③ 烃源岩综合评价分析认为,平下下亚段有利烃源岩主要分布在研究区的中东部区域,平下上亚段有利烃源岩主要分布在研究区的东南部区域。     

Improved Seismic Stratigraphy of the Mesozoic Weddell Sea

We present a compilation of more than 45,000 km of multichannel seismic data acquired in the last three decades in the Weddell Sea. In accordance with recent tectonic models and available drillhole information, a consistent stratigraphic model for depositional units W1–W5 is set up. In conjunction with existing aeromagnetic data, a chronostratigraphic timetable is compiled and units W1.5, W2 and W3 are tentatively dated to have ages of between 136 Ma and 114 Ma. The age of W3 is not well constrained, but might be younger than 114 Ma. The data indicate that the thickest sediments are present in the western and southern Weddell Sea. These areas formed the earliest basins in the Weddell Sea and so the distribution of Mesozoic sediments is in accordance with the tectonic development of the ocean basin. In terms of Cenozoic glacial sediments, the largest depocenters are situated in front of the Filchner–Ronne Shelf, i.e. at the Crary Fan, with a thickness of up to 3 km.