Dereverberation of marine reflection seismic data by a spatial combination of predictive deconvolution and velocity filtering     

C. Samson  G. F. West 《Marine Geophysical Researches》1995,17(1):1-15

Contamination of seismic reflection records at early times by first-order water reverberations can be especially severe during survey operations over hard and flat sea floors on the continental shelf or in lake environments. A new dereverberation scheme based on two classical techniques — predictive deconvolution and velocity filtering — has been developed to address this problem. The techniques are combined spatially to take advantage of their complementary offset- and time-dependent properties. Stage I of the scheme consists of applying predictive deconvolution at short offset. The data are previously conditioned by a normal moveout correction with the water velocity which restores the periodicity of the reverberations in the offset-time plane and enhances the performance of deconvolution. Stage II of the scheme involves velocity filtering in the common-midpoint domain which is particularly effective at long offset where the moveout difference between primary reflections and reverberations is largest. The dereverberation scheme is well suited for the initial processing of large volumes of data due to the general availability of cost-effective deconvolution and velocity filtering algorithms in seismic processing software packages. Practical implementation issues are illustrated by a field example from the GLIMPCE survey in Lake Superior.Lithoprobe Publication No. 475.  相似文献   

Design of a 3D Chirp Sub-bottom Imaging System     

Jonathan M. Bull  Martin Gutowski  Justin K. Dix  Timothy J. Henstock  Peter Hogarth  Timothy G. Leighton  Paul R. White 《Marine Geophysical Researches》2005,26(2-4):157-169

Chirp sub-bottom profilers are marine acoustic devices that use a known and repeatable source signature (1–24 kHz) to produce decimetre vertical resolution cross-sections of the sub-seabed. Here the design and development of the first true 3D Chirp system is described. When developing the design, critical factors that had to be considered included spatial aliasing, and precise positioning of sources and receivers. Full 3D numerical modelling of the combined source and receiver directivity was completed to determine optimal source and receiver geometries. The design incorporates four source transducers (1.5–13 kHz) that can be arranged into different configurations, including Maltese Cross, a square and two separated pairs. The receive array comprises 240 hydrophones in 60 groups whose group-centres are separated by 25 cm in both horizontal directions, with each hydrophone group containing four individual elements and a pre-amplifier. After careful consideration, it was concluded that the only way to determine with sufficient accuracy the source–receiver geometry, was to fix the sources and receivers within a rigid array. Positional information for the array is given by a Real Time Kinematic GPS and attitude system incorporating four antennas to give position, heading, pitch and roll. It is shown that this system offers vertical positioning accuracy with a root-mean-square (rms) error less than 2.6 cm, while the horizontal positioning rms error was less than 2.0 cm. The system is configured so that the Chirp source signature can be chosen by software aboard the acquisition vessel. The complete system is described and initial navigational and seismic data results are presented. These data demonstrate that the approach of using fixed source-receiver geometry combined with RTK navigation can provide complete 3D imaging of the sub-surface.  相似文献   

南海北缘东部盆地油气资源研究   总被引：5，自引：0，他引：5  

杜德莉  王树民  陈弘  陈泓君  万玲 《海洋地质与第四纪地质》2001,21(3):67-74

南海北缘东部的珠江口盆地及台西南盆地蕴藏着十分丰富的油气资源，根据区域构造背景、盆地发育分布的特点及中、新生代的油气地质条件，结合含油气构造、油气田、油气井的分布规律，利用油气资源评价的理论、方法，对区内的油气资源进行了综合研究，并按照油气资源状况划分出油气富集区、油气潜力区、油气远景区，在此基础上，再进一步划分出4条油气富集带、11条油气潜力带、8条油气远景带，充分显示了该区石油、天然气的分布规律和油气地质特点，为商业性的勘探开发和理论研究奠定了基础。  相似文献   

南海陆坡天然气水合物成藏的构造环境   总被引：36，自引：4，他引：36  

王宏斌  张光学  杨木壮  梁金强  梁劲  钟广见 《海洋地质与第四纪地质》2003,23(1):81-86

南海是西太平洋最大的边缘海之一，其复杂的构造演化，形成了构造特征迥异的南海陆缘，有利于天然气水合物的发育，南海地区在中中新统以上发育了上中新统，上新统和第四系3套地层，3套地层所对应的地质时期的沉降速率在纵横向上的差别均较为悬殊，总体而言，南海第四纪整体沉降速率较大，为天然气水合物压力场环境的形成提供了有利条件，南海复杂的构造背景形成了丰富多彩的构造地质体，特定的构造地质体与水合物形成关系密切，这里讨论了滑塌体、泥底辟、增生楔等构造地质体在南海的分布情况，分析了上述构造体与气体水合物地震标志BSR之间的关系，以及特殊构造带在南海的展布规律，提出了特殊的造带中天然气水合物的成藏模式。  相似文献   

海洋天然气水合物的地震识别方法研究   总被引：21，自引：2，他引：21  

马在田  耿建华  董良国  宋海斌 《海洋地质与第四纪地质》2002,22(1):1-8

天然气水合物作为21世纪新的自然能源将为人类的生存发展服务。20世纪60年代证实，俄罗斯西伯利亚的麦索亚哈气田为典型的天然气水合物形成的气田，70年代又在海底发现了固体天然气水合物岩样。1971年，RStoll首先将地震剖面中的似海底反向层解释为海洋天然气水合物存在的标志，后来被深海钻探证实，从此地震方法成为大面积研究天然气水合物的重要手段。天然气水合物既是潜在能源，也是影响环境和形成灾害的因素之一，因此，研究天然气水合物是人类在21世纪的重要课题。探讨海洋天然气水合物的地震识别方法，由于这项工作刚刚起步，还没有做出具体的成果，在此只能根据我们仅有的工作和参照国外分开的出版物，以及出国访问得到的有关资料进行分析，提出我们的一些基本设想，与各位专家探讨。  相似文献   

太平洋三海区热液烟囱物的氧同位素特征及形成温度     

WU Shi ying  LIU Yan guang  ZHANG Dao jian  BAI Li ming  WU Jun rui 《海洋科学进展》2001,(3)

使用氧同位素方法 ,测试了西太平洋马里亚纳岛弧、马里亚纳海槽、冲绳海槽和东太平洋加拉帕戈斯裂谷的海底热液烟囱和硫化物全岩样品。结果表明 :马里亚纳岛弧上的埃斯梅拉尔达破火山口的热液硫化物的形成温度最高 (达 2 75℃ ) ,而成为高温产物的代表 ;冲绳海槽和加拉帕戈斯裂谷烟囱 ,表现为中高温类型 ,其氧同位素温度在 1 5 0℃左右 ;马里亚纳海槽以蛋白石为主要矿物的烟囱物 ,则显示出典型的低温热液类型 ,少量黄铁矿砂试样则表现出中温类型特征。但上述区域大都不同程度地存在有闪锌矿、黄铁矿、黄铜矿等中高温热液矿物 ,说明研究区除马里亚纳海槽明显有中低温热液活动类型外 ,其它区域皆具备中高温热液活动特征  相似文献   

广东红海湾、珠江口及电白—阳江近海第四纪沉积     

康长生  杨胜明  廖志良 《热带海洋学报》1997,(1)

根据物探和钻探资料，研究区内第四纪沉积物可分为两部分，下部地震反射结构复杂，斜层理发育，粒度较粗，为晚更新世产物；上部的地震反射结构简单，呈水平状或近水平状结构，粒度较细，为全新世沉积。  相似文献   

Southern Segment of the European Geotraverse — a wide-angle seismic refraction experiment in the Sardinia Channel     

C. Peirce  P. J. Barton 《Marine Geophysical Researches》1992,14(3):227-248

The Sardinia Channel dataset was collected as part of the European Geotraverse (EGT)—a 4000 km seismic refraction line running from Northern Norway to the Sahara, designed to investigate the structure of the lithosphere beneath Europe. Wideangle seismic data recorded by ocean bottom seismometers deployed in the Sardinia Channel as part of the Southern Segment of the EGT, together with gravity data, were used to constrain the final crustal model. In the centre of the Channel the crust is identified as thinned continental in nature, with a crystalline thickness of 10 km overlain by 4 km of sediments and 2.5 km of water in the most extended region. High velocities in the lower crust in the central region are thought to represent an area of underplating or intrusion by igneous material caused by extension related to the opening of the Tyrrhenian Sea. The crust overlies an anomalously low velocity upper mantle.  相似文献   

A technique for conducting seismic refraction experiments on the ocean bed using bottom shots     

R. E. Kirk  K. Robertson  R. B. Whitmarsh  P. R. Miles 《Marine Geophysical Researches》1991,13(2):153-160

A technique has been devised for firing arrays of bottom shots on the ocean bed in depths upto 4000 m or more. Ten kilogram explosive charges are dropped from the surface while the shooting ship is navigated acoustically. They are detonated at preset times by an electronic timer which initiates an electrical detonator, detonating cord and cast PETN/TNT explosive. Ranges to ocean bottom seismographs, and the shot instants, can be calculated from the arrival-time differences of the direct and surface-reflected water waves. The accuracy, which is dependent on water-depth and range, was better than 22 m in range and 14 msec in shot instant for our experiments.  相似文献   

冲绳海槽天然气水合物BSR的地震研究   总被引：8，自引：0，他引：8       下载免费PDF全文

唐勇  金翔龙  方银霞  孙鹏  李新 《海洋学报》2003,25(4):59-66

根据多道地震反射资料分析,在冲绳海槽南部和中部发现了拟海底反射层(BSR)现象。通过对海底异常反射层的振幅特征、速度异常和AVO属性分析,说明该BSR可能反映了天然气水合物的存在,并发现冲绳海槽断层与天然气水合物的形成有密切关系。  相似文献