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本文介绍一种声遥测海底平面层系声阻抗分布的模拟实验结果。实验在油漆厂冷却水池中进行,采用取样平均迭代的反演方法,对三介质层系的遥测结果与实测值较好地接近。 相似文献
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下刚果盆地油气勘探策略 总被引：9，自引：0，他引：9
西非被动大陆边缘诸盆地是目前油气勘探的重点和热点地区。通过对各个含油气盆地的基本石油地质特征和勘探潜力研究表明,下刚果盆地富含油气,资源潜力及勘探潜力极大。通过对下刚果盆地油气成藏特点的分析,探讨了对下刚果盆地的勘探策略,指出宏观上应重点关注下刚果盆地,平面上和纵向上应该对不同的地区和层系采取不同的勘探策略。平面上重点关注深水区,兼顾浅水区;纵向上,深水区以盐上勘探层系为主,浅水区以盐下勘探层系为主。 相似文献
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《海洋地质前沿》2021,37(10)
下刚果-刚果扇盆地位于西非被动大陆边缘,是典型的裂谷与被动陆缘叠合盆地。该区以往的研究多集中于盐上层系,对基底断裂研究较少。以构造分析为基础,探讨了基底断裂复活及其对盐上层系构造变形和油气分布的影响。结果表明,研究区盐下裂谷层系具有"两坳夹一隆"的构造格局,大西洋枢纽带夹持于内裂谷带和外裂谷带之间;基底断裂复活主要发生在紧邻大西洋枢纽带西侧、呈狭长带状分布的基底断裂复活带,断裂复活形式主要表现为继承性,其次为构造反转;基底断裂复活不仅对盐上层系的构造变形具控制作用,而且为油气从盐下层系向盐上层系运移提供了良好的垂向通道条件,是外裂谷带盐下油气向盐上层系运移的关键部位。 相似文献
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南海西南部地区发育了多种类型的新生代沉积盆地。各种类型的盆地上有各自的结构特征和演化历史。在走滑－周缘前陆盆地－－曾母盆地发育了渐新－中中新统层系、晚中新统层系和上新统一第四第层系第三套地层曾母盆地经历了三个发育阶段，拉张剪切盆地－－万安盆地发育了下第三系一下渐新统层系、上渐新统一中新统层系和上中新统一第四系层系三套地怪。万安盆地经历了卤个发育阶段。 相似文献
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林俊轩 《中国海洋大学学报(自然科学版)》1996,(4)
采用场匹配处理法反演层系介质参数，在匹配处理前先对层系模型参数进行预估。参数预估将大大地减少匹配运算时间。模拟实验的反演结果与取样实测结果相当符合 相似文献
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南海西南部新生代盆地类型及演化历史 总被引：4，自引：0，他引：4
南海西南部地区发育了多种类型的新生代沉积盆地，各种类型的盆地具有各自的结构特征和演化历史，走滑－周缘前陆盆地－曾母盆地发育了渐新－中中新统层系，晚中新统层系和上新－第四系层系第三套地层，曾母盆地经历了三个发育阶段，拉张剪切盆地－万安盆地发育下第三系－下渐新统层系，上渐新统一中中新统层系和上中新统一第四系层系三套地层，万安盆地经历了四个发育阶段。 相似文献
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科尔占地区位于滨里海盆地阿斯特拉罕-阿克纠宾斯克隆起带东南部的比伊克扎尔次级隆起上,该地区广泛发育下二叠统孔谷组盐岩,以盐岩沉积为界,它将整个剖面划分为盐上层系（以碎屑岩为主的含油气层系）和盐下层系（以碳酸盐岩为主的含油气层系）两个大的含油气层系,石炭系为盐下层系中主要的含油气层系之一。通过对研究区唯一的盐下井K井岩屑及其薄片的详细观察,并结合该井测井资料,分析了石炭系的沉积特征,并对其沉积相进行了划分与描述。K井石炭系主要发育3种类型沉积相,分别为深水浊积扇相、斜坡相和台地相,其中深水浊积扇相可进一步划分为内扇、中扇和外扇3个亚相,台地相划分为滩间洼地和台内滩2个亚相。利用K井钻探结果,结合区域资料,初步预测出科尔占地区早石炭世和中石炭世末期沉积相带的平面分布特征。 相似文献
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《海洋地质前沿》2017,(10)
南海北部湾盆地涠西南凹陷下渐新统涠二段油气勘探程度相对较低,作为一套湖平面上升期形成的富泥地层系统,内幕薄砂体成因和展布规律较复杂。笔者从构造沉积充填演化史入手,开展内幕多期次基准面旋回变化的剖析,识别出上、中、下3个四级层序。其中中层序早期为砂岩集中发育层段,进一步分析和追踪落实,该套砂岩呈正韵律牵引流特征,具有多期叠置、水动力较强、自北向南进积的特点,推测为受盆缘一系列断阶强烈活动影响而在洼中—斜坡带稳定分布的大型低位三角洲砂体。由于其沉积背景及储盖组合类型与该区烃源和油气运聚条件配置较好,因此,预测涠二段中层序早期低位—海侵域应是研究区重要的勘探层系,尤其是来自东北方向的长源低位三角洲则更具有广阔的勘探前景。 相似文献
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High-frequency propagation close to an active surf line is explored with 12and 100-kHz propagation paths together with measurements of bubble clouds, bubble size distributions, and waves. Breaking waves inject massive bubble plumes that are mixed downwards from the roller region by intense turbulence. If these injections follow one another at intervals less than the time taken for the bubbles to rise to the surface, acoustic signals will be continuously blocked, forming an acoustical barrier that effectively inhibits any propagation. Occasionally, waves break seaward of this barrier. In this case, dense bubble clouds are mixed down beneath the air entrainment zone, but there is sufficient time for them to disappear before succeeding breakers, allowing intermittent high-frequency propagation recharge the bubble field. The duration and shape of signal dropouts are then determined by the selective removal of bubbles by buoyancy and dissolution. In addition to turbulence created by the air entrainment process, a lower level of continuous background turbulence may be generated by interaction of residual currents with the wave boundary layer. Our observations illustrate the variable character of acoustic blocking by bubble clouds and serve as a basis for quantitative analysis of these effects with a 2D propagation model coupled to 2D models of bubble cloud evolution and background turbulence 相似文献
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El-Khamy S.E. Abdel-Alim O.A. Rushdi A.M. Banah A.H. 《Oceanic Engineering, IEEE Journal of》1989,14(4):384-395
The synthesis of linear and planar arrays of desired omnidirectional intensity patterns is considered. A novel approach that utilizes the relation between the array intensity pattern and the correlation function of the used feeding sequence, or code, is adopted. The basic theory of such code-fed arrays is reviewed, and it is shown that almost omnidirectional patterns result when codes with sharp autocorrelation functions are used as the feeding sequences. Examples of omnidirectional linear and planar arrays fed with Barker codes, Kuttruff-Quadt trial-and-error two-dimensional binary codes, and nonbinary Huffman-type codes are presented. The results have direct application in underwater communication systems, public address systems, and acoustical imaging systems 相似文献
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The small-scale roughness of the sea surface acts as an important link in air-sea interaction processes. Radar and sonar waves are scattered by short surface waves providing the basis for remote sensing methods of the sea surface. At high wind speeds, breaking waves occur. Bubbles penetrate into the water and drastically increase acoustical reverberation, transmission loss and ambient noise. Thus, the development of short waves and wave breaking have to be known to apply radar remote sensing to the surface and to deduce from radar backscatter which sonar conditions prevail. To measure the wind dependence of short waves an experimental device was constructed for use from stationary platforms. It is nearly all-weather capable and can easily be handled by a crane. On the other hand, frequencies of short waves measured in a fixed position are extremely frequency shifted by currents. This limits the usefulness of tower-based measurements, e.g., the short wave modulation by wind and waves or currents can only be estimated in a rough approximation. Consequently, a buoy was developed to reduce the frequency shifts. The principle of the buoy is to drift in the local surface current and to follow the amplitudes of long waves. Therefore, short waves are measured in facets of long waves and the Doppler shifts are minimized. The wind is measured at a constant height above the long wave profile and relative to the moving facets. The paper describes the conventional measuring device and points out the necessity of the drifting buoy system. Examples of wind and wave spectra are presented and short wave modulations by long waves are depicted, too. From these measurements, new insights in short wave behaviour have to be expected 相似文献
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杨振华 《中国海洋大学学报(自然科学版)》1997,(4)
采用声学方法精密测定汞被高压强压入储油岩样的渗入体积，对岩芯孔隙结构测定中的汞体积计量方法作了重要改进。本方法以无水酒精作为计量工作介质，在其中发射声波，通过对汞界面反射声波的识别，进行非接触的声学测量，从根本上解决了当前国内外采用的电阻法，电容法无法避免的由于汞腐蚀或油污染而要求经常进行与有毒汞接触的清洗，并且确保了计量系统工作性能的长期稳定与准确可靠。在０．０１ＭＰａ至５０ＭＰａ压强范围内连续计量，量程０～１０ｍｌ，准确度０．０１ｍｌ。 相似文献
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While the destruction caused by a tsunami can vary significantly owing to near- and onshore controls, we have only a limited quantitative understanding of how different local parameters influence the onshore response of tsunamis. Here, a numerical model based on the non-linear shallow water equations is first shown to agree well with analytical expressions developed for periodic long waves inundating over planar slopes. More than 13,000 simulations are then conducted to examine the effects variations in the wave characteristics, bed slopes, and bottom roughness have on maximum tsunami run-up and water velocity at the still water shoreline. While deviations from periodic waves and planar slopes affect the onshore dynamics, the details of these effects depend on a combination of factors. In general, the effects differ for breaking and non-breaking waves, and are related to the relative shift of the waves along the breaking–non-breaking wave continuum. Variations that shift waves toward increased breaking, such as steeper wave fronts, tend to increase the onshore impact of non-breaking waves, but decrease the impact of already breaking waves. The onshore impact of a tsunami composed of multiple waves can be different from that of a single wave tsunami, with the largest difference occurring on long, shallow onshore topographies. These results demonstrate that the onshore response of a tsunami is complex, and that using analytical expressions derived from simplified conditions may not always be appropriate. 相似文献
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Robert A. Dalrymple 《Applied Ocean Research》1989,11(4):170-175
Small amplitude water waves propagating from a narrow rectangular channel into a wider rectangular channel are examined to determine the reflection coefficients and the diffraction patterns associated with the channel transition. An eigenfunction expansion method is used for the full range of channel transitions, while a variational solution is developed for the case when only planar waves are reflected in the upwave channel. Significant reflections occur when the wavelength of the waves in the wider channel corresponds to multiples of the channel width. 相似文献
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《Oceanic Engineering, IEEE Journal of》2010,35(1):12-27
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《Oceanic Engineering, IEEE Journal of》1989,14(1):4-16
A method of formulating the scattered acoustical field for certain types of hard bodies through the use of well-known exact solutions for the simple semi-infinite wedge and/or corner is presented. The method yields a representation of the total sound field for all frequencies and satisfying all boundary conditions. Relevant hard-wedge solutions for harmonic line sources and for plane waves are reviewed. Such solutions, which are rigorous, represent the total sound field as a superposition of directional line sources and sinks at the wedge vertex. A method of representing multiple scatter from combinations of wedges, allowing the explicit solution of the case of a truncated wedge, is introduced. This method uses the classic self-consistent algorithm for multiple scatter, together with a rigorous representation of vertex-diffracted fields 相似文献
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The Polar Floats Program, an adaptation of midlatitude SOFAR float technology to the polar regions, is used to monitor subsurface circulation patterns over large spatial and temporal scales as well as to track mesoscale features in near realtime. The program is comprised of three major components that are now under development: an 80-Hz float transducer, American and French sea-ice-deployable listening stations using ARGOS data telemetry (ARS and SOFARGOS, respectively), and the software needed for real-time tracking. The adaptation of SOFAR technology to the planar regime demands modifications of the existing design from both environmental and acoustical standpoints. The authors describe the development and use of SOFAR technology within a relatively small sector of the north polar region that encompasses several thousand kilometers around Fram Strait (located between Greenland and Spitsbergen) 相似文献