首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 187 毫秒
1.
遥感的空间信息反映一定范围内象元在空间上的关系,对成像光谱仪遥感数据而言,空间结构变代表一个局部区域中各象元之间光谱辐射能量的关联状态,在图像上反映为灰度变化,利用空间信息来开拓图像分析技术可获得遥感目标很高的正确识别率,变差函数是联系遥感目标和图像中空间变化特征的有用工具,实验变差函数的计算结果表明遥感目标种类与变差图之间的定量化空间关系,可以在成像光谱图像处理中发挥作用。  相似文献   

2.
基于相控地质统计学反演的薄储层岩性、物性预测   总被引:1,自引:0,他引:1  
针对河流相储层厚度薄、纵向叠置严重、横向变化快、常规确定性反演方法受地震频带限制难以准确刻画的特点,尝试应用基于MCMC算法的地质统计学方法进行反演,以提高分辨率和储层预测精度,并全程应用成岩储集相控制建模,以便从储层地质学的角度加强模型约束,促进概念模型向定量模型的转化,建立合理的反映地下实际情况的油藏物性模型。具体实现方法是,首先利用对岩性识别敏感的测井曲线重构拟声阻抗曲线,再以声阻抗为中间变量,对岩性、物性参数空间变异性进行双重变差函数分析,最后基于MCMC算法实现了成岩储集相控制的地质统计学反演。得到的三维岩性、阻抗及孔隙度模型,其纵向分辨率为1ms,既可以很好地展现不同期次砂体的叠置关系、隔夹层的分布以及沉积旋回纵、横向演变规律,又可以实现物性变异方向沿河道砂体弯曲方向变化的趋势,同时可对地震资料的多解性进行有效限制。  相似文献   

3.
通过岩心、录井、测井等资料分析认为研究区为辫状河三角洲沉积,沉积主体为辫状河三角洲前缘亚相,只在研究区北端为辫状河三角洲平原沉积。研究区Guaduas组经历了两期湖平面的升降旋回,十几个短期旋回。由于辫状河道频繁改道,河漫滩以及水下分流河道间湾沉积形成的隔夹层分布广泛,储层的连通性变差,形成非常复杂的油水系统。储集砂体主要是水下分流河道与河口坝,物性受沉积微相的控制,河口坝砂体储层物性最好,水下分流河道次之,辫状河道最差。  相似文献   

4.
大洋多金属结核矿床的二维地质统计学模型   总被引:3,自引:0,他引:3  
采用二维地质统计学方法对太平洋CC区内不同类型金属结核矿区的地质特征进行了定量分析,通过对地质采样数据分析,计算,多角度的实验变化函数对比,建立了丰度,Mn,Cu,Co,Ni5个变量的理想理论变差函数,通过点交叉验证,确定最佳估计参数,建立矿床数学模型,运用克立格方差对其估计结果,精度进行了分析。  相似文献   

5.
深海现代沉积有机质碳同位素组成变化的古气候证据   总被引:2,自引:0,他引:2  
分析了南沙海洋深海连续沉积岩心剖面中有机碳同位素,研究了只有机质碳同位素组成变化因素及其与古气候旋回的关系,各种有机地球化学指标综合判识表明,该岩心剖面沉积有机质碳同位素组成变化未受有机质性质和成岩作用的影响,主要与古气候变迁关系密切。其ε^13C低值段对应于晚第四纪末次冰期,高值段对应于末次间冰期。  相似文献   

6.
南沙群岛海区晚第四纪深海碳酸盐沉积作用   总被引:5,自引:1,他引:5  
根据5个柱样分析,讨论了冰期一间冰期碳酸盐沉积作用变化,南沙海区碳酸盐旋回在3500m以浅表现为大西洋旋回,源于冰期陆源碎屑物质的稀释作用,相反,在3500m以下出现太平洋碳酸钙旋回,文中根据浮游有孔虫的溶解指数和种属数量讨论了冰期-间冰期溶解作用变化。  相似文献   

7.
主频计算法对测井曲线沉积旋回的精细分析   总被引:5,自引:0,他引:5  
用主频计算法对长庆气田主力储层中下奥陶统马家沟组马五1段碳酸盐岩的自然伽玛测井曲线进行了分析,得出其主要沉积旋回周期为100、57、36和26ka,基本与米兰科维奇旋回的地球自转偏心率和地轴倾角变化周期相一致,因崦,可以认为储层的沉积旋回是地球自转偏心率和地轴倾角变化引起气候周期性变化形成的,其中又以偏心率影响最大,表明主频计算法用于测井曲线进行分辩率较高的沉积旋回分析是可行的。  相似文献   

8.
近2万年来南海北部与西部碳酸盐旋回及其古海洋学意义   总被引:13,自引:3,他引:13  
通过对南海北部与西部5个活塞取心钻孔的碳酸盐系统分析,并结合部分年代学和有孔虫溶解指数资料研究,认为位于CCD界面以上,以稀释作用为主的半深海陆坡区碳酸盐沉积旋回有如下特点:近2万年来区碳酸盐旋回可以分为6期,并具有一定的普遍性和可比性;与同位素和气候旋回相比,碳酸盐旋回在时间上存在的“超前”现象,超前时间为1-2kaB.P.;早冰后期,约相当于7.0-8.0kaB.P.期间,区内存在的一次低碳酸  相似文献   

9.
皖南风尘堆积序列氧化物地球化学特征与古气候记录   总被引:29,自引:3,他引:29  
根据安徽宣城向阳剖面64个样品系统的氧化物地球化学测试结果,分析讨论了皖南更新世风尘堆积序列氧化物地球化学特征及其所记录的气候变迁规律。结果表明:该区气候总体上以湿热为主,淋溶及氧化作用较强;近0.8Ma以来经历了8次大的干冷-暖湿气候旋回,显示本区中、晚更新世气候变迁具有全球一致性特点;中更新世以来本区气候演变的总趋势是由湿热向偏于偏凉发展。  相似文献   

10.
台西南盆地晚新生代地质演化分析   总被引:2,自引:0,他引:2  
通过对构造沉降、断裂活动、岩浆活动、构造应力场等分析,认为台西南盆地晚新生代地质演化存在两个旋回,即渐新世-中中新世受南海扩张控制、陆缘主动裂陷-沉降旋回和晚中新世-第四纪受台湾弧-陆碰撞影响、陆缘被动拉张-活化旋回。  相似文献   

11.
The study of phytoplankton distributions and processes in these waters has been stimulated in recent years (1) by the synoptic views of surface pigment afforded by the Coastal Zone Color Scanner (CZCS) aboard the NIMBUS-7 satellite; (2) by rapid developments in bio-optical oceanography toward the estimation of in situ photosynthetic rate; (3) by use of sediment traps and geochemical tracers to determine the flux of organic matter from the euphotic zone; and (4) by measurements of new production based on the utilization of nitrate by the plankton. The evolution and rationale of the Joint Global Ocean Flux Study of ocean biogeochemical cycles and ocean climate changes serve to focus much of the work. In that context, a major goal is to assess new/export production on large time and space scales accessible to date only by remote sensing.  相似文献   

12.
济阳坳陷博兴洼陷西部沙三段层序地层   总被引:1,自引:0,他引:1  
选取以基准面为参照面的高分辨率层序地层学的理论与分析技术,对博兴洼陷西部沙三段开展层序地层分析工作。在博兴洼陷沙三段识别出5个层序界面和4个较大规模的洪泛面,由此将研究层段划分为4个长期基准面旋回(相当于3级层序),并通过长期旋回内部次级转换面的识别,细分出8个中期旋回(大致相当于4级层序)。通过对比建立了研究区的高分辨率层序地层格架,并分析了各层序的地层发育特征。以层序格架为基础,探讨了研究区各层序的沉积演化特征,建立了辫状三角洲—浊积扇层序发育模式,认为研究区辫状三角洲和浊积扇均具有加积作用特点;斜坡区为辫状三角洲发育区,而洼陷区为浊积扇发育区;中期基准面旋回下降期辫状三角洲发育,上升期浊积扇发育;浊积扇体的发育规模与湖泛规模相关。综合分析认为,浊积扇是形成岩性圈闭的主要储集砂体类型,其发育的有利层位是MSC8、MSC7、MSC6、MSC5旋回的上升半旋回,岩性圈闭发育的有利区是博兴南部斜坡坡折带之下的洼陷区。  相似文献   

13.
沾化凹陷复式生烃系统及其对油气成藏的控制作用   总被引:14,自引:0,他引:14  
陆相断陷盆地油气勘探实践证明,丰富的油气资源与富含有机质的生烃洼陷具有十分密切的关系。陆相断陷湖盆多沉降中心、多物源和充填演化的多旋回性,形成了多套生油层系和多种油气储集相带组合,并在空间上形成了多个含油气系统。油源对比表明沾化油区存在5种不同地球化学特征的原油,常形成“一源多藏”和“多源一藏”的单源或混源组合特点,它们分别来自沙四上段烃源岩、沙三段烃源岩、沙一段烃源岩,以及来自沙四上段与沙三段混源和来自沙三段与沙一段混合。由不同地球化学特征的烃源岩层组成的复式生烃系统所形成的油气藏在空间分布上具有一定的规律性。复式生烃系统的特点控制了复合含油气系统的形成和分布。  相似文献   

14.
Dissolved organic matter (DOM) plays a crucial role in both the carbon cycle and geochemical cycles of other nutrient elements, which is of importance to the ma...  相似文献   

15.
Comparison of the δD deuterium record in the ice cores at the Antarctic Vostok and Dome C stations with the δ18 oxygen isotope in bottom oceanic sediments has elucidated the boundaries of glacial cycles in the late Pleistocene and revealed their inner symmetry: the longer the cycles, the more distant they were from the interglacial that occurred approximately 400 kyr ago. The symmetry is also manifested in the reversal of the sawtooth sequence of the cycles in that period. Wavelet analysis shows that symmetry was induced by amplitude modulation of climate oscillations on the precession and obliquity time scales and by frequency modulation on the scales of the eccentricity of the Earth’s orbital motion around the Sun.  相似文献   

16.
Distinctive light–dark color cycles in sediment beneath the Benguela Current Upwelling System indicate repetitive alternations in sediment delivery and deposition. Geochemical proxies for paleoproductivity and for depositional conditions were employed to investigate the paleoceanographic processes involved in creating these cycles in three mid-Pleistocene intervals from ODP Sites 1082 and 1084. Concentrations of total organic carbon (TOC) vary between 3.5 and 17.1%. Concentrations of CaCO3 vary inversely to TOC and Al, which suggests that both carbonate dissolution and terrigenous dilution contribute to the light–dark cycles. Opal concentrations are independent of both TOC and CaCO3, therefore eliminating diatom production and lateral transport of shelf material as causes of the light–dark cycles. δ13Corg and δ15Ntot values do not vary across light–dark sediment intervals, implying that the extent of relative nutrient utilization did not change. The stable δ15Ntot values represent a balanced change in nitrate supply and export production and therefore indicate that productivity was elevated during deposition of the TOC-rich layers. Parallel changes in concentrations of indicator trace elements and TOC imply that changes in organic matter delivery influenced geochemical processes on the seafloor by controlling consumption of pore water oxygen. Cu, Ni, and Zn are enriched in the darker sediment as a consequence of greater organic matter delivery. Redox-sensitive metals vary due to loss (Mn and Ba) or enrichment (Mo) under reducing conditions created by TOC oxidation. Organic matter delivery impacts subsequent geochemical changes such as carbonate dissolution, sulfate reduction and the concentration of metals. Thus, export production is considered ultimately responsible for the generation of the color cycles.  相似文献   

17.
深海沉积中的钙质超微化石是古海洋表层生产力的替代性标志之一。通过对南海南部ODP1143站第四纪沉积中超微化石分析,从绝对丰度和堆积速率、Florisphaera profunda百分含量及碳同位素三个方面探讨了该区第四纪表层海水古生产力的变化特征。结果显示,1.56Ma以来南海南部表层海水古生产力呈现两种不同时间尺度的变化。一是随冰期-间冰期旋回而变化,间冰期时,表层海水生产力高,而冰期时则降低;另一种则是大约40万年的长周期变化,自1.56Ma以来,可以分成四个大的旋回,每个旋回内表层海水古生产力又经历了从低到高再到低的变化。  相似文献   

18.
The effects of the bubble breaking process on the atmospheric geochemical cycles of the elements Fe, Cu and Zn were investigated, in situ, in the estuarine waters of Narragansett Bay, Rhode Island. Enrichment, as defined by the metal-to-sodium ratios in the aerosols produced compared to their ratio in bulk water, occurred for the three metals investigated. The extent and potential geochemical importance of the process were different for each element. Iron enrichment was quite low (enrichment factor (EF) <100) and constant, and scavenging of iron from the water column and subsequent enrichment on the aerosols produced did not appear to occur. Copper enrichment on the aerosols was 200 and appeared to be influenced by both microlayer and scavenging effects. In addition, copper enrichment appears to be correlated to biological processes. Zinc enrichment was approximately the same as Cu; however, a strong scavening effect appeared to occur, suggesting scavenging of Zn by rising bubbles. Scavenging effects suggest that open-ocean enrichments for Cu may be slightly higher than observed here and a great deal higher for Zn.Geochemical implications of the data, together with other existing data, indicate that the sea is an insignificant source of Fe to the atmosphere. The sea may be a significant source (contributing on the order of 10% or more) of the total annual quantity of Cu and Zn to the atmosphere.  相似文献   

19.
The successful use of near-surface anomalous signals, exhibited in all petroliferous basins, must lead to great development in petroleum exploration. The elementary equations and methods for objective and accurate separation of anomalous signals from background signals are the most critical requirements in these surface geochemical surveys. Therefore, we have worked up a series of fundamental equations and methods for eliminating surface interference and influences of geological conditions on anomaly intensities and recognizing multi-type anomalies of uni- and multi-variates, by using statistics, fractal geometry, wavelet analysis and artificial neural networks. These equations illustrate that the threshold (i.e. the boundary between background and micro-seepage anomalies) is determined by means, standard deviations and prior probabilities of background and micro-seepage anomalies when multi-normality is met, and that the traditional equation for the threshold (background mean plus one or two standard deviations) is not correct. In the face of many new equations and methods, it is important how to comprehensively use them to resolve the problems in geochemical surveys. A geochemical survey in the south slope of the Dongying depression, eastern China provides a good opportunity to address this issue. The anomalies obtained with the traditional equation do not reflect oil/gas fields. This study reveals three problems in the previous data-processing and anomaly recognition: (1) the surface interference caused by the variation of soil composition was not identified and removed, (2) the influence of caprock thickness on anomaly intensities was not revealed and eliminated, and (3) the micro-seepage (related to oil/gas pools) and seepage (related to faults) anomalies were not separated and correctly recognized. Furthermore, the interaction of these problems makes the data-processing and anomaly recognition more difficult. To ensure effective elimination of the surface interference and caprock thickness influence and correct recognition of uni-variate anomalies, we iteratively applied the wavelet-analysis-based methods to eliminate the surface interference and caprock thickness influence, and statistical methods with new fundamental equations to recognize uni-variate anomalies of seepage and microseepage. And then, multi-variate anomalies of seepage and microseepage were recognized with our fundamental equations and the corresponding methods. In the results, the seepage anomalies display a string-bead-shaped pattern and are distributed along faults, and the micro-seepage anomalies are ring-shaped and coincide with oil/gas pools, sandbodies or traps. Therefore, reprocessing of geochemical data with our fundamental equations and methods combined in an iterative manner can resolve the complicated problems in data-processing and anomaly recognition and thus greatly improve the predictive capability of surface geochemical survey.  相似文献   

20.
卷波式弧形台阶海岸防浪墙   总被引:1,自引:0,他引:1  
海岸线整治工程固然需要修筑防波护岸堤防,而滨海城市开发滩地也多结合交通旅游,建设体现海滨特色、可供观赏海景的滨海大道。故尝试采用既能适应多级潮位的波浪回卷,又能增强墙体稳定性,体形新颖的弧形台阶海岸防浪墙。本文联系广东省湛江市海岸线整治工程已建成的滨海大堤实例①,表述此种荟萃海塘、挡潮、防浪、土地开发、交通、旅游多功能的防浪墙设计的基本点,透过波浪模型试验,探求在各级风浪作用下,不同的潮水位、波高、波周期组合条件时,弧形台阶式防浪墙前回卷波浪的性能、波态、波压力及浮托力的变化规律,进而确定两级台阶弧形组合防浪墙的体形。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号