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1.
相移加校正变范围三维叠前深度偏移 总被引：4，自引：0，他引：4
理论和实践证明,三维叠前深度偏移是目前最精确的地震波场为成像方法,该文在二维叠前深度偏移及偏移速度模型建立方法研究的基础上,进一步研究了变范围三维叠前深度偏移叠加方法和软件,用三维相移加校正方法在炮集上实现三维叠前深度偏移,并根据三维速度模型构造形态,自动确定偏移后成像孔径进行变范围移叠加,提高三维构造形态清晰度。该方法属全波方程偏移,具有成像精度高,对模型适应性强的特点。 相似文献
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波动方程三维叠前深度偏移研究,已成为近年国内外众多油气勘探科研单位的研究焦点,其关键问题之一是借助于软硬件及其匹配的进步,以求解决计算量庞大的障碍。作者在本文中从油田实际出发,提出了一套并行波动方程辛几何算法三维叠前深度偏移方法与处理流程,运用32节 点集群式并行机,完成了XJWZ地区150km的二维和WJT地区126km^2的三维地震资料波动方程叠前深度偏移处理。其成像的效果,在信噪比、分辨率、深层复杂构造成像等方面均获得了显著改善。 相似文献
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三维平面波叠前时间偏移技术实用性不强,浅层成像信噪比较低,在计算过程中内存开支大,并行节点有效利用率低,且不具有断点保护功能,无法适用于大规模叠前偏移成像处理。为了提高三维平面波叠前时间偏移的实用化水平,从平面波叠前时间偏移原理和实现方案出发,针对存在的问题,提出了相应的解决方案,包括通过倾角滤波方法压制浅层的偏移成像噪声,提高浅层成像信噪比;采用分层成像方案,减小计算过程中的内存开支,提高并行节点的有效利用率;开发断点保护功能,考虑了长时间偏移计算中的断点风险。在应用于某工区实例资料处理后表明,经优化后的平面波叠前时间偏移技术较原平面波偏移具有更好的成像精度,并且具备了大规模数据处理能力。 相似文献
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《物探化探计算技术》2015,(5)
叠前深度逆时偏移技术是一种基于精确波动方程的偏移技术,不受地下倾角和介质横向速度变化的影响。江苏油田苏北盆地地下地质构造复杂,断裂系统发育,用常归Kirchhoff叠前深度偏移技术很难准确成像,针对此实际情况,对陈堡三维进行了叠前逆时深度偏移处理,结果表明,在高陡倾角处断面成像上,叠前逆时深度偏移剖面较Kirchhoff叠前深度偏移剖面的品质有很大提高,断面清晰,断层归位准确,为后续解释工作打下了良好的基础。 相似文献
5.
波动方程叠前深度偏移在地震勘探成像处理方面起着不可替代的作用。随着高性能大规模并行计算机技术的发展,波动方程叠前深度偏移计算在地震勘探中的应用有了很大进步。在波动方程叠前深度偏移处理中,庞大的数据规模与海量计算对计算性能提出了很高的要求。曙光4000A超级计算机系统是我国目前峰值速度最快的商用超级计算机系统,无论是硬件平台建设还是应用软件的配置方面,都具有良好的应用性能。基于该系统设计的三维波动方程叠前深度偏移(炮域)PSDM软件,采用动态负载平衡并行计算模式,具有较高的计算效率,高度的可扩展性和可靠性。 相似文献
6.
根据“西部煤炭资源高精度三维地震勘探技术”项目中对国内外各种深度域偏移成像方法和特点的调研成果．对各类深度域成像的算法和特点进行了总结,指出不同深度域成像算法选取原则主要依据构造复杂程度和横向速度变化情况。结合克希霍夫叠前三维深度域偏移模块说明深度域偏移原理和工作流程,并以实例说明叠前深度域成像能够解决因第四系地层厚度剧烈变化造成的下覆煤层赋存形态被扭曲、深度误差大、断层平面位置不准确等问题。该实例中,叠前深度域成像划分的煤层深度比时间域偏移剖面解释结果向下移动40多m,钻探结果证实其解释的煤层深度和断层位置比较准确。 相似文献
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对地下地质构造正确成像是地震勘探的最终目的,由于三维地震资料采集不可能都沿垂直构造走向的方向进行,这就为地震资料的三维处理带来了许多困难.本文将三维叠后拉东投影偏移思想应用于三维叠前处理,提出了三维叠前投影偏移算法.利用拉东投影变换的原理,将整个三维叠前数据体投影到一系列各方向的径向线上,各方位角的构造都包含在其中某条或多条径向剖面上.投影完成后,形成一系列的独立的二维叠前测线,于是可采用二维叠前偏移成像方法来实现各径向线的叠前偏移,当各径向剖面偏移完成后,在切片上进行反投影,从而最终形成三维叠前偏移结果.实际应用表明,用该方法进行三维叠前深度偏移时,深度偏移剖面对横向分辨率有所提高,对陡地层和小断层的成像效果有所改善. 相似文献
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井间地震成像技术在解决复杂构造、油藏描述等方面具有较高的成像精度。高斯束偏移成像方法兼具Kirchhoff积分偏移的灵活性以及波动方程偏移的精确性,不仅计算速度快,并且运算精度高。在地面地震高斯束叠前深度偏移成像方法研究的基础上,首次将其应用于井间地震资料成像。针对井间理论模型试算,同井间地震波动方程逆时偏成像方法相比,井间地震高斯束叠前深度偏移方法成像精确,计算效率高。将该方法应用在某海上油田井间地震资料成像中,这里所研究的井间地震高斯束叠前深度偏移成像方法的成像结果,比海上三维地震剖面具有更高的分辨率,解决了海上三维地震分辨率不足的难题,可为油气田目的层微小构造识别提供有利依据,具有较好的应用前景。 相似文献
11.
铁板砂是一种特殊的沉积地貌,其性质和形成演化涉及海洋沉积动力、海洋工程地质等学科方向,对海岸防护、航运安全和海洋工程建设有重要影响。介绍了铁板砂的概念、特征和分布,以铁板砂形成和演化机制为主线,从原生沉积、冲刷分选和液化渗流3种模式出发,对国内外铁板砂研究现状进行总结和论述,分析了3种模式的优缺点和适用条件,从研究思路和研究方法等方面对铁板砂的研究趋势进行了展望,指出基于海洋土力学与沉积动力学相结合的思路,开展水体-床面-床内耦合的多要素同步观测,构建机制清晰的物理模型和定量评价的数学模型是今后铁板砂研究的发展方向。 相似文献
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论中国前寒武纪地质时代及年代地层的划分 总被引：7，自引：1，他引：7
Wang Hongzhen 《地球科学》1986,(5)
本文讨论了前寒武纪地质时代和年代地层划分的原则和命名,提出建立隐生宙、原生宙和显生宙。隐生宙包括冥古代和太古代;原生宙分始元代、中元代和新元代。划分中的重要改变是根据新的年龄值数据将五台群归入太古代,将长城系底界改为1700Ma;并根据蠕虫-须腕动物群的出现,将震旦纪归入古生代。文中还阐述了作者对前寒武纪时代划分的新观点。 相似文献
14.
Brian P. Hedlun Jessica K. Cole Amanda J. Williams Weiguo Hou Enmin Zhou Wenjun Li Hailiang Dong 《地学前缘(英文版)》2012,3(3):273-288
The Rehai Geothermal Field,located in Tengcbong County,in central-western Yunnan Province, is the largest and most intensively studied geothermal held in China.A wide physicochemical diversity of springs(ambient to ~97℃;pH from≤.8 to≥9.3) provides a multitude of niches for extremophilic microorganisms.A variety of studies have focused on the cultivation,identification,basic physiology,taxonomy,and biotechnological potential of thermophilic microorganisms from Rehai.Thermophilic bacteria isolated from Rehai belong to the phyla Firmicutes and Deinococcus-Thenmts. Firmicutes include neutrophilic or alkaliphilic Anoxybacillus,Bacillus,Caldalkalibacillus.Caldanaerobacier, Laceyella,and Geobacillus,as well as thermoacidophilic Alicyclobacillus and Sulfobacillus. Isolates from the Deinococcus-Thermus phylum include several Meiothermus and Thennus species.Many of these bacteria synthesize thermostable polymer-degrading enzymes that may be useful for biotechnology. The thermoacidophilic archaea Acidianus.Melal/osp/utera.and Suljolobus have also been isolated and studied.A few studies have reported the isolation of thermophilic viruses belonging to Siphoviridae(TTSP4 and TTSPIO) and Fuselloviridae(STSVl) infecting Thennus spp.and Suljolobus spp..respectively.More recently,cultivation-independent studies using 16S rRNA gene sequences, shotgun metagenomics,or "functional gene" sequences have revealed a much broader diversity of microorganisms than represented in culture.Studies of the gene and mRNA encoding the large subunit of the ammonia monooxygenase(imioA) of ammonia-oxidizing Archaea(AOA) and the tetraether lipid erenarchaeol. a potential biomarker for AOA.suggest a wide diversity,but possibly low abundance,of thermophilic AOA in Rehai.Finally,we introduce the Tengchong Partnerships in International Research and Education(PIRE) project,an international collaboration between Chinese and U.S.scientists with the goal of promoting international and interdisciplinary cooperation to gain a more holistic and global view of life in terrestrial geothermal springs. 相似文献
15.
《Geoforum》2017
By engaging with ‘pro-anorexia’ and ‘food porn’ on the Internet, this paper explores eating in cyberspace. Reflecting on the ways in which virtual, but affective, consumption is central to both food porn and pro-anorexia websites, the paper asks what the act of eating ‘triggers’ and produces, connects and displaces. It traces how eating in, and through, cyberspace shapes the biological materialities of bodies whilst also collapsing neat distinctions between offline and online worlds. Virtual vectors of spectating, salivating and digesting are disembodied and yet corporeal. Eating is seen to take place beyond and among bodies and to be dissipated both spatially and temporally. As such, cyberspace is outside and other to lived corporeality, and yet also folded into and productive of the intimate geographies and embodied subjectivities of everyday lives. As eating takes myriad forms across the de-materialised viscerality of the Internet, it also emerges as central to the production and ‘matter(ing)’ of cyberspace itself; this is (an) eating space in which what is eaten, by whom and with what bodies, perpetually shifts. Thus, seeking to contribute to geographical scholarship on affect and food, this paper engages with eating as both the subject of enquiry and also as a productive pathway into an interrogation of cyberspace and its place within the affective productions of the everyday. It suggests that this is a key site in which to explore the intimate socialities, materialities and biopolitics of food. 相似文献
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At Ducabrook property, central Queensland, the mid-Viséan Ducabrook Formation has yielded a diverse vertebrate fauna (fish and one tetrapod taxon) from a thin unit among siltstone interbedded with sandstone, minor oolitic limestone and conglomerate. Five lithofacies can be distinguished: the Oolitic Facies, distinguished by oolitic limestone and straight parallel ripple crests; the Sandy Facies, composed of plane-laminated and current-rippled sandstones; the Conglomeratic Facies, represented by pebble conglomerate displaying planar cross-bedded megaripples; the Silty Facies of siltstone with abundant calcrete nodules or sand/silt/clay interlaminations; and the Lime-Flake Facies, characterised by abundant locally derived lime flakes. The last includes the fossiliferous tetrapod unit. The Oolitic Facies was deposited in the inner (proximal) and outer (distal) zones of an estuary, based on identification of tidal sedimentary structures (e.g. mud drapes) and estuarine oolitic fabrics; the Lime-Flake Facies and Silty Facies were deposited in the estuary and lower reaches of a river and its surrounds; and the Sandy and Conglomeratic Facies represent braid-river deposits. Overall, the sequence represents intermittent deposition throughout an estuary, both within the tidal channel and the surrounding tidal flats, with additional deposition from the feeder river. The tetrapod unit, from the Lime-Flake Facies, represents a twin-peaked storm-induced flood event onto the tidal channel floor. The vertebrate bones have a shared taphonomic history and have undergone only local transport. The tetrapod and fish were spatially and temporally concurrent, probably in a shallow tidally influenced proximal estuarine habitat experiencing monsoonal conditions. Estuarine adaptations of these vertebrate taxa can explain migration along shallow-water continental shelves between the supercontinents during the Late Devonian and Early Carboniferous. 相似文献
17.
At Segura, granitic pegmatite veins with cassiterite and lepidolite, hydrothermal Sn–W quartz veins and Ba–Pb–Zn quartz veins intruded the Cambrian schist–metagraywacke complex and Hercynian granites. Cassiterite from Sn–W quartz veins is richer in Ti and poorer in Nb and Nb+Ta than cassiterite from granitic pegmatite. Wolframite from Sn–W quartz veins is enriched in ferberite component. The Sn–W quartz veins contain pyrrhotite, arsenopyrite, sphalerite, chalcopyrite, stannite, matildite and schapbachite and the Ba–Pb–Zn quartz veins have cobaltite, pyrite, sphalerite, chalcopyrite, galena and barite, which were analyzed by electron microprobe. The presently abandoned mining area was exploited for Sn, W, Ba and Pb until 1953. Stream sediments and soils have higher concentrations of metals than parent granites and schists. Sn, W, B, As and Cu anomalies found in stream sediments and soils are associated with Sn–W quartz veins, while Ba, Pb and Zn anomalies in stream sediments and soils are related to Ba–Pb–Zn quartz veins. Sn, W, B, As, Cu, Ba, Pb and Zn anomalies in stream sediments and soils are also related to the respective old mining activities, which increased the mobility of trace metals from mineralized veins to soils, stream sediments and waters. Stream sediments and soils are sinks of trace elements, which depend on their contents in mineralized veins and weathering processes, but Sn, W and B depend mainly on a mechanic process. Soils must not be used for agriculture and human residence due to their Sn, B, As and Ba contents. Waters associated with mineralized veins were analyzed by flame atomic absorption spectroscopy (FAAS) and ICP-AES have high As, Fe and Mn and should not be used for human consumption and agriculture activities. The highest As values in waters were all related to Sn–W quartz veins and the highest Fe and Mn values were associated with the Ba–Pb–Zn quartz veins. No significant acid drainage was found associated with the old mine workings. 相似文献
18.
Geochemical evolution of halogen-enriched granite magmas and mineralizing fluids of the Zinnwald tin-tungsten mining district,Erzgebirge, Germany 总被引：10，自引：0，他引：10
We remelted and analyzed crystallized silicate melt inclusions in quartz from a porphyritic albite-zinnwaldite microgranite dike to determine the composition of highly evolved, shallowly intruded, Li- and F-rich granitic magma and to investigate the role of crystal fractionation and aqueous fluid exsolution in causing the extreme extent of magma differentiation. This dike is intimately associated with tin- and tungsten-mineralized granites of Zinnwald, Erzgebirge, Germany. Prior research on Zinnwald granite geochemistry was limited by the effects of strong and pervasive greisenization and alkali-feldspar metasomatism of the rocks. These melt inclusions, however, provide important new constraints on magmatic and mineralizing processes in Zinnwald magmas.The mildly peraluminous granitic melt inclusions are strongly depleted in CAFEMIC constituents (e.g., CaO, FeO, MgO, TiO2), highly enriched in lithophile trace elements, and highly but variably enriched in F and Cl. The melt inclusions contain up to several thousand ppm Cl and nearly 3 wt% F, on average; several inclusions contain more than 5 wt% F. The melt inclusions are geochemically similar to the corresponding whole-rock sample, except that the former contain much more F and less CaO, FeO, Zr, Nb, Sr, and Ba. The Sr and Ba abundances are very low implying the melt inclusions represent magma that was more evolved than that represented by the bulk rock. Relationships involving melt constituents reflect increasing lithophile-element and halogen abundances in residual melt with progressive magma differentiation. Modeling demonstrates that differentiation was dominated by crystal fractionation involving quartz and feldspar and significant quantities of topaz and F-rich zinnwaldite. The computed abundances of the latter phases greatly exceed their abundances in the rocks, suggesting that the residual melt was separated physically from phenocrysts during magma movement and evolution.Interactions of aqueous fluids with silicate melt were also critical to magma evolution. To better understand the role of halogen-charged, aqueous fluids in magmatic differentiation and in subsequent mineralization and metasomatism of the Zinnwald granites, Cl-partitioning experiments were conducted with a F-enriched silicate melt and aqueous fluids at 2,000 bar (200 MPa). The results of the experimentally determined partition coefficients for Cl and F, the compositions of fluid inclusions in quartz and other phenocrysts, and associated geochemical modeling point to an important role of magmatic-hydrothermal fluids in influencing magma geochemistry and evolution. The exsolution of halogen-charged fluids from the Li- and F-enriched Zinnwald granitic magma modified the Cl, alkali, and F contents of the residual melt, and may have also sequestered Li, Sn, and W from the melt. Many of these fluids contained strongly elevated F concentrations that were equivalent to or greater than their Cl abundances. The exsolution of F-, Cl-, Li-, ± W- and Sn-bearing hydrothermal fluids from Zinnwald granite magmas was important in effecting the greisenizing and alkali-feldspathizing metasomatism of the granites and the concomitant mineralization.Editorial Handling: B. Lehmann 相似文献
19.
对重金属和辐射污染的土壤和地下水的微生物修复 总被引：1，自引：0，他引：1
由重金属和辐射产生的环境污染在世界范围内产生了一系列问题.利用特殊的微生物如金属还原和耐金属细菌对环境中的金属和辐射污染进行处理具有非常好的前景.现场的生物修复的成功应用将对清除污染环境中的重金属和辐射提供潜在方法.最近的研究还关注于了解在微生物群体内重金属和辐射对微生物的作用.生物毯和生物膜是在生物修复中具有代表性的两种微生物群落的机能.金属的种类和价态变化、转移过程以及微生物代谢作用是对金属和辐射生物修复的三种重要的组成部分.结合以上三方面,可以更好的了解自然中的微生物和生物修复过程之间的关系. 相似文献
20.
The plutonic rocks in the Kwandonkaya complex, located within the NYG province of Nigeria, have some hypersolvus granites composed mainly of orthoclase microperthite and interstitial annite. These are inferred to have formed from a relatively F-poor, and relatively dry felsic melt. During cooling, Al–Si order was not completely achieved when the inversion of sanidiness to orthoclase and exsolution occurred. A majority of the granites contain intermediate to low microcline with annite to siderophyllite. The samples were incipiently modified in the subsolidus at very low fluid–rock ratios. Drusy granites result from resurgent boiling and volatile loss, which produced orthoclase-dominant feldspar and zoned zinnwaldite, with microcline lining cavities, whereas late loss of volatiles resulted in low microcline and zinnwaldite and metasomatism associated with cassiterite-topaz mineralization. Mica composition in both types of drusy granite is similar and seems to have been fluid-buffered. Albitization was rock-buffered and resulted in variable degree of Al–Si order in K-feldspar and mild modification of mica composition. Key factors affecting both the degree of Al–Si order of K-feldspar and mica compositions at Kwandonkaya seem to be the degree of volatile build-up and loss, and extent of fluid–rock interactions. 相似文献