Intra-survey reservoir fluctuations – implications for quantitative 4D seismic analysis     

Veronica Omofoma  Colin MacBeth  Hamed Amini 《Geophysical Prospecting》2019,67(2):282-297

During the time taken for seismic data to be acquired, reservoir pressure may fluctuate as a consequence of field production and operational procedures and fluid fronts may move significantly. These variations prevent accurate quantitative measurement of the reservoir change using 4D seismic data. Modelling studies on the Norne field simulation model using acquisition data from ocean-bottom seismometer and towed streamer systems indicate that the pre-stack intra-survey reservoir fluctuations are important and cannot be neglected. Similarly, the time-lapse seismic image in the post-stack domain does not represent a difference between two states of the reservoir at a unique base and monitor time, but is a mixed version of reality that depends on the sequence and timing of seismic shooting. The outcome is a lack of accuracy in the measurement of reservoir changes using the resulting processed and stacked 4D seismic data. Even for perfect spatial repeatability between surveys, a spatially variant noise floor is still anticipated to remain. For our particular North Sea acquisition data, we find that towed streamer data are more affected than the ocean-bottom seismometer data. We think that this may be typical for towed streamers due to their restricted aperture compared to ocean-bottom seismometer acquisitions, even for a favourable time sequence of shooting and spatial repeatability. Importantly, the pressure signals on the near and far offset stacks commonly used in quantitative 4D seismic inversion are found to be inconsistent due to the acquisition timestamp. Saturation changes at the boundaries of fluid fronts appear to show a similar inconsistency across sub-stacks. We recommend that 4D data are shot in a consistent manner to optimize aerial time coverage, and that additionally, the timestamp of the acquisition should be used to optimize pre-stack quantitative reservoir analysis.  相似文献   

Self-centering friction spring dampers for seismic resilience     

Wei Wang  Cheng Fang  Yashuo Zhao  Richard Sause  Shuling Hu  James Ricles 《地震工程与结构动力学》2019,48(9):1045-1065

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上海海洋邮轮旅游的发展策略研究          下载免费PDF全文

郑玉香  于群  左海榕 《海洋开发与管理》2018,35(1):7-13

海洋邮轮旅游产业在现代旅游业的发展中有极大的潜力。近些年来,邮轮旅游产业被誉为"漂浮在黄金水道上的黄金产业"。随着中国经济的发展,我国邮轮旅游业迅速兴起,使多级邮轮市场开始向中国倾斜,成为带动中国经济发展的新动力。文章首先对比了邮轮旅游业国内外的研究现状和理论分析方法,并介绍了上海海洋邮轮旅游业目前的发展现状;其次用"SWOT"分析法的角度讨论了上海邮轮旅游业面临的机会和威胁;最后针对上海海洋邮轮旅游产业,分别从改善环境、扩大宣传、丰富航线和完善港口设施等方面提出了邮轮旅游业的长期发展方向。  相似文献   

基于区域监测站的BDS定轨策略分析     

王乐  黄观文  张勤  燕兴元  秦志伟  王利  崔博斌 《大地测量与地球动力学》2018,38(5):497-503

围绕影响轨道精度和实时性的5个要素（模糊度分类固定、测站数量、定轨弧长、太阳光压模型和多系统组合）展开研究，得出区域测站分布下的定轨优选策略。实验表明，选取中国区域27个均匀分布的地面区域监测站，利用72 h弧长观测数据，采用ECOM 5参数简化太阳光压摄动模型、BDS/GPS双系统联合定轨可达到较好的精度，其中GEO卫星轨道精度约291 cm，IGSO/MEO卫星轨道精度优于11 cm。若BDS单系统采用上述策略进行定轨，也可达到GEO卫星299 cm和IGSO/MEO卫星14.4 cm的近似等价定轨精度。  相似文献   

基于EEMD-SARIMA的对流层延迟预测模型研究     

任超  刘中流  梁月吉  甘祥前 《大地测量与地球动力学》2018,38(9):953-957

在无气象数据的条件下，提出一种基于集合经验模态分解（EEMD）和季节性自回归移动平均模型（SARIMA）的对流层延迟（ZTD）预报新方法，并分别选取长春、上海、乌鲁木齐3个地区4个季节的ZTD数据进行预测分析。结果表明，基于EEMD-SARIMA的ZTD改正预报模型能够满足不同地区、不同季节下的ZTD估计需求，是一种高精度的ZTD预报方法。  相似文献   

GPS约束下陇西地区断裂带现今滑动速率的非连续接触模拟研究     

孟庆筱  景鹏旭  何申海  党学会 《大地测量与地球动力学》2018,38(12):1227-1231

以中国地壳运动观测网络1999、2001、2004和2007年4期GPS观测数据为边界条件，使用非连续接触有限元技术构建陇西块体二维有限元模型，在摩擦系数不确定性分析基础上，计算区内主要断裂带滑动速率。结果表明，现今地壳形变运动状态下陇西块体的北东向运动在海原断裂附近受到鄂尔多斯块体、阿拉善块体阻碍，陇西块体周缘的海原断裂带、老虎山断裂、西秦岭北缘断裂呈现左旋走滑特征，滑动速率为3.5 mm/a、2.2 mm/a和1.9 mm/a，说明在青藏高原推挤作用下以上关键部位正在进行快速的构造应变积累。  相似文献   

Galileo广播星历评估及其对定位精度的影响     

韩德强  党亚民  庞辉  薛树强  杨强  张龙平 《大地测量与地球动力学》2018,38(11):1165-1169

分析现阶段伽利略空间信号的精度，并评估伽利略广播星历及其对单点定位的影响。统计30 d健康卫星广播星历，结果表明，FOC和IOV两种类型的广播星历卫星轨道误差优于0.8 m，并且径向误差最小，法向误差次之，切向误差最大；伽利略卫星的钟差误差精度达到1.0 ns；从空间信号测距误差对伽利略卫星进行整体分析，广播星历精度优于1.0 m，FOC与IOV卫星精度相当；用广播星历进行事后单点定位的精度可以达到dm级。  相似文献   

Long‐term monitoring of a mercury contaminated estuary (Ria de Aveiro,Portugal): the effect of weather events and management in mercury transport          下载免费PDF全文

J. P. Coelho  P. Pato  B. Henriques  A. Picado  A. I. Lillebø  J. M. Dias  A. C. Duarte  M. E. Pereira  M. A. Pardal 《水文研究》2014,28(2):352-360

The main aim of this research was to assess the mercury transport from an estuarine basin with a background of anthropogenic contamination during a spring tidal cycle (year 2009) and compare it with two previous tidal cycles (years 1994 and 1999), as part of a long‐term monitoring program. Results showed that effective mercury transport occurs both in the dissolved and particulate fractions (0.18 and 0.20 kg per tidal cycle, respectively), and despite an overall decrease in environmental contamination, results more than double previous findings on particulate transport in the system. These findings result essentially from changes in the tidal prism (net export of 2 million m³ of water), given that both dissolved and particulate concentrations did not increase over time. Hydrodynamic simulations were performed to evaluate the effect of physical disturbance (dredging) and weather events (increased freshwater flow) in these processes, and results suggest the increased freshwater flow into the system as the main forcing function for the mercury transport increment. These results highlight the importance of long‐term monitoring programs, since despite an overall improvement in local contamination levels, the enhancement of transport processes through hydrological changes increases environmental pressure away from the contamination source. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

冻融循环下花岗岩剪切蠕变试验与模型研究     

张峰瑞  姜谙男  杨秀荣  申发义 《岩土力学》2020,41(2):509-519

为探讨冻融对寒区工程岩石剪切蠕变特性的影响，以吉林省辉白隧道花岗岩为研究对象，对经历不同冻融循环次数的试样开展细观特征分析和剪切蠕变试验。试验结果表明：（1）随着冻融次数的增加，试样裂隙、孔隙不断扩展，岩石表面损伤现象愈发明显；（2）试样主要以中小孔隙为主，孔隙度随着冻融次数的增加呈非线性增长趋势；（3）随着冻融循环次数增加，蠕变变形量和蠕变速率逐渐增大，而蠕变时长、破坏应力和长期强度均呈现明显降低趋势。根据试验结果，进行冻融岩石非定常蠕变参数的表达，提出了冻融岩石损伤黏性元件，构建了花岗岩冻融剪切蠕变本构模型。将蠕变试验曲线和理论模型拟合曲线进行对比，验证了模型的正确性和适用性。通过对蠕变参数进行敏感性分析，研究了其对花岗岩蠕变变形的影响，并给出了蠕变参数随冻融循环次数的变化规律。该研究结果对于寒区岩体工程长期稳定性评价具有指导意义。  相似文献   

Hydrogeophysical modelling of Hisarcik (Kütahya) geothermal field,western Turkey     

Serkan Üner  Gülçin Özürlan Ağaçgözgü  Doğa Düşünür Doğan 《Geophysical Prospecting》2019,67(8):2176-2195

Western Anatolia hosts many low-to-moderate and high-temperature geothermal sources in which active faults play a dominant role to control the recharge and the discharge of geothermal fluid. In this study, we used the two-dimensional geoelectric structure of Kütahya Hisarcık geothermal field, and created a conceptual hydrogeophysical model that includes faults, real topographical variations and geological units. The temperature distribution and fluid flow pattern are also investigated. The depth extension of Hisarcık Fault, electrical basement and low resistivity anomalies related to the presence of geothermal fluid are determined by using resistivity studies in the area. Numerical simulations suggest that Hisarcık fault functioning as a fluid conduit primarily enables hot fluid to be transported from depth to the surface. It is shown that the locations of predicted outflow vents coincide with those of hot springs in the area.  相似文献