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HUANG Ling YANG Guang-da HAN Li-guo .Geophysical Exploration Company of Jilin Petroleum Group Co. Ltd Songyuan China .Jilin Petroleum Group Company Songyuan China .College of GeoExploration Science Technology Jilin University Changchun China 《吉林大学学报(地球科学版)》2006,(Z2)
深层地震勘探野外资料采集的关键是在保证原始资料一定信噪比的基础上,同时兼顾分辨率,激发井深是决定资料品质的重要因素之一。通过对虚反射滤波作用分析,提出了充分利用虚反射能量设计最佳激发井深,增强下传地震波能量的采集方法。理论分析和试验资料表明,在高速层下4~7m的最佳激发岩性深度是深层勘探的理想井深。 相似文献
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论三维等时线叠加反偏移中的有关问题 总被引:6,自引:2,他引:6
孙建国 《吉林大学学报(地球科学版)》2002,32(3):273-278
利用几何射线理论和一种考虑了积分域边缘贡献的二维稳想法,研究了三维等时线叠加反偏移中的反偏移场,反偏移加权函及反偏移孔径。结果证明,在有限孔径条件下,反偏移场的结构比已发表的结果要复杂和多。即使在最简单的条件下,反偏移场也是由反偏移信号的反偏移噪声(孔径效应)叠加而成的。而且,反偏移场的结构强烈地依赖于反偏移孔径边缘的位置。为了消除孔径效应,应采用最佳反偏移孔径和针对有限孔径的加权函数。根据定义,最佳反偏移孔径为稳相点的第一和第二Fresnel区之和。在第一Fresnel区内,有限孔径和加权函数与文献中所给出的加权函数完全一致。而在第二Fresnel区内,有限孔径加权函数为常规的加权函数与一窗函数的乘积。在反偏移孔径的边缘上,有限孔径加权函恒取零值。 相似文献
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Lithoprobe and industry seismic profiles have furnished evidence of major zones of easterly dipping Grenville deformed crust extending southwest from exposed Grenville rocks north of Lake Ontario. Additional constraints on subsurface structure limited to the postulated Clarendon–Linden fault system south of Lake Ontario are provided by five east–west reflection lines recorded in 1976. Spatial correlations between seismic structure and magnetic anomalies are described from both Lake Ontario and the newly reprocessed New York lines.In the Paleozoic to Precambrian upper crust, the New York seismic sections show: (1) An easterly thickening wedge of subhorizontal Paleozoic strata unconformably overlying a Precambrian basement whose surface has an apparent regional easterly dip of 1–2°. Minor apparent normal offsets, possibly on the order of tens of meters, occur within the Paleozoic section. The generally poorly reflective unconformity may be locally characterized by topographic relief on the order of 100 m; (2) Apparent local displacement on the order of 90 m at the level of the Black River Group diminishes upward to little or no apparent offset of Queenston Shale; (3) Within the limited seismic sections, there appears to be no evidence that the complete upper crustal section is vertically or subvertically offset; (4) Dipping structure in the Paleozoic strata (15° to 35°) resembles some underlying Precambrian basement elements; (5) The surface continuity of inferred faults constituting the Clarendon–Linden system is not strongly supported by the seismic data.Beneath the Paleozoic strata, the seismic sections show both linear and arcuate reflector geometry with easterly apparent dips of 15° to 35° similar to the deep structures imaged on seismic lines from nearby Lake Ontario and on Lithoprobe lines to the north. The similarity supports an extension of easterly dipping Central Metasedimentary Belt structures of the Grenville orogen from southern Ontario to beneath western New York State.From a comparison of the magnetic and gravity fields with the New York seismic sections, we suggest: (1) The largely nonmagnetic Paleozoic strata appear to contribute negligibly to magnetic anomalies. Seismically imaged fractures in the New York Paleozoic strata appear to lie mainly west of a positive gravity anomaly. The relationship between magnetic and gravity anomalies and the changes in the geometry of interpreted Precambrian structures remains enigmatic; (2) North to northeast trending curvilinear magnetic and gravity anomalies parallel, but are not restricted to the principal trend of the postulated Clarendon–Linden fault system. Paleozoic fractures of the Clarendon–Linden system may partly overlie a southward extension of the Composite Arc Belt boundary zone. 相似文献
45.
Seismic profiles and well data from the Doukkala basin unravel the structure of the Palaeozoic basement and suggest that this coastal zone of western Morocco was affected by a compressive phase during the Frasnian. This resulted in the formation of upright, plurikilometric folds associated with reverse faults (North Doukkala), and of asymmetrical folds associated with mostly west verging ramps (South Doukkala). Folding involved all pre-Upper Frasnian formations and caused partial or total hiatus of Upper Frasnian–Strunian strata. This event can be correlated with the orogenic phase reported from more internal domains of the Morocco Hercynian belt, where it is referred to as the ‘Bretonne’ or ‘Eovariscan’ phase. To cite this article: H. Echarfaoui et al., C. R. Geoscience 334 (2002) 13–20 相似文献
46.
Audrey GalvéAlfred Hirn Jiang MeiJosep Gallart Béatrice de VoogdJean-Claude Lépine Jordi DiazWang Youxue Qian Hui 《Earth and Planetary Science Letters》2002,203(1):35-43
New wide-angle reflection and refraction seismic data provide constraints on the structure of the upper lithosphere, and test models of its evolution to raise the northeastern part of the Tibetan Plateau. Amplitudes observed for reflections from the crust-mantle boundary are sufficiently large to suggest that there is no significant partial melt in the deep crust. The data show an increase of the crustal thickness between terranes from north of the Kun Lun Fault into the Qang Tang of central Tibet, and a contrast among their intracrustal images and compositions. In the north, P and S velocities are consistent with a dominantly felsic composition and show that only the upper crust thickened. South of the Kun Lun Fault a thicker crust made of two layers could result from the superposition of the originally thin crust of the Bayan Har terrane on the lower part of the crust of the domain to the north, which upper crust it shoved and thickened. Different modes of crustal thickening, either by thickening of individual layers or superpositions and imbrication among them appear to work jointly to raise the topography. 相似文献
47.
在中国大陆科学钻探孔区 (江苏省东海县南部 )进行了系统的地球物理调查 ,包括二维地震测网和专门的地震剖面 ,大地电磁法和位场方法等 .地震调查表明 ,在超高压变质岩出露区上地壳充满了反射体 ,包括倾斜反射体与上拱的反射弧 .本文介绍大陆科学钻探先行研究中地震调查的成果 .根据大陆科学钻探预先导孔的岩芯和测井资料、井旁VSP和数值模拟结果证实 ,高波速的榴辉岩体、破碎断裂带和大型韧性剪切带都可引起倾斜的地震反射 ,而上拱的弧形反射体则是由近似直立的榴辉岩体和其中的破碎带的综合反映 .由于地壳深部广泛分布着经受变质的岩石 ,上述研究结果对标定地壳中的反射地震信号具有一定意义 相似文献
48.
Seismic investigations along the western sector of Alpha Ridge, Central Arctic Ocean 总被引:2,自引:0,他引:2
Wilfried Jokat 《Geophysical Journal International》2003,152(1):185-201
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总结不对称抽道集共反射面元叠加方法的工作经验,提出自由观测面自由反射界面不对称抽道集共反射面元叠加方法的处理思路和计算方法。在自由观测面的条件下,反射界面可分为简单倾斜平面、规则曲面和自由反射界面三种情况,针对不同情况讨论共反射面元的叠加方法。综合一般情况下的共反射面元叠加方法,提出了“鳞片法”的处理思路。 相似文献