Key Problems and Countermeasures in CO2 Flooding and Storage

Based on literature research in combination with the practice of CO₂ flooding and storage in Jilin Oilfield, this study assesses the key problems in CO₂ flooding and storage, proposing the corresponding countermeasures from five aspects of CO₂ gas source condition, namely geological condition evaluation, scheme design incoordination with other production methods, economic and effectiveness evaluation, together with dynamic monitoring and safety evaluation. The re...     

高聚物外包盾构隧道离心机振动台试验研究

为了验证非水反应聚氨酯高聚物(后文简称高聚物)外包盾构隧道具有减震性能,对高聚物外包盾构隧道模型和无外包隧道模型,采用离心机振动台进行对比试验。针对中密砂土围岩,在不同阵型特征的地震波输入下,对比有无高聚物外包隧道加速度、频谱、隧道动力响应和地表沉降,分析高聚物的减震性能。试验结果表明:在不同地震激励的工况下,对于有无高聚物外包的隧道模型,其加速度和频谱差别不大;二者隧道各点上的动应变平均相差31.32%;高聚物外包层隧道模型地表的最终沉降分别比无外包隧道模型和自由场地表沉降约小20%和50%。试验证明高聚物对盾构隧道有减震作用,此试验研究为高聚物在今后的工程应用提供参考依据。     

凝胶堵漏技术在阳山矿区漏失地层中的应用

甘肃省文县阳山矿区地质构造复杂,地层破碎蚀变强烈,多层位漏失,钻探施工漏失现象普遍。在研究地层漏失机理的基础上试验应用了聚合物凝胶堵漏技术。ZK2232孔的现场应用表明,聚合物凝胶堵漏剂与其他惰性桥堵剂配合使用,能很好地解决钻进过程中的恶性漏失问题,堵漏效果较好。在堵漏施工中,聚合物凝胶堵漏不受漏失通道的限制,能够通过挤压变形进入裂缝和孔洞空间,最终达到封堵漏层的目的。     

煤田地质超深孔钻探工艺

在对深部煤田地质钻孔钻进工艺研究的基础上,有针对性选择使用聚合物泥浆,解决了基浆配制用水及泥浆抗地表水水质污染问题。通过改变双管钻具长度和改换取心钻头的切削具,满足软硬互层对钻头钻进效率的影响。在煤系地层钻进中,除采用常规的单管钻具钻进外,在见煤预告下过后,采用加长双管取心钻具,既可保证了回次进尺,又可保证岩心的采取。多项措施落实,不仅解决了生产中的一些难题,收到了较好的效果,而且创造了河北省煤田地质局煤田地质单孔钻探深度2 009.12m的新纪录,为今后深部钻孔的施工积累了经验。     

Flood magnification on the River Rhine

Flooding on the German Rhine during the 20th century was tested for trends and assessed to identify causal mechanisms driving worsening of flooding. A review of previous research outlines the range of impacts due to climate change, land‐use shifts, and river regulation. Analysis of hydrologic data, especially of the long record at Cologne, documents statistically significant increases in both flood magnitudes and frequencies. Specific‐gauge analysis, which isolates the effects of channel modification, documents that 20th century river engineering has caused little of the observed increase in flooding on the German Rhine. Precipitation records from the Rhine basin confirm that flood magnification has been driven by upstream factors, including an increase in flood‐producing precipitation of roughly 25% during the past 100 years and increases in runoff yields. In addition, agricultural land‐use records suggest that flood magnification can be partially explained by 20th century trends documenting intensification and industrialization of German agriculture. Copyright © 2005 John Wiley & Sons, Ltd.     

瞬变电磁方法在山西某煤矿区水患调查的应用

由于历史原因,煤炭资源整合矿区老窑采空区分布及积水情况不清,成为煤矿安全生产的重大隐患。利用煤炭采空区电性特征,选择以瞬变电磁勘探为主的大面积勘探,可以发挥其高效率、高精度的特点,辅以其它勘探手段进行综合勘查,能快速有效地确定采空区的位置及赋水情况。本次研究是采用瞬变电磁勘探为主的勘探方法对山西一煤矿区水患情况进行调查。首先根据矿区的测井资料对地电条件进行分析,通过针对性的试验,选择合理的施工参数。利用多种方法将采集数据进行处理分析,得到反应不同地质特征的剖面及平面图件,特别是利用专用软件得到煤层富水性目标分析对比图,更明确直观地反应采空区的位置及富水性。此次水患调查,基本查明了矿区内采空区及积水区位置、范围等情况,部分分析成果得到钻孔验证,证明采用瞬变电磁法勘探为主的勘查手段,在本矿区进行水患调查成果显著,为矿井的水患防治工作提供了可靠的资料依据。     

River flood seasonality in the Northeast United States: Characterization and trends

The New England and Mid‐Atlantic regions of the Northeast United States have experienced climate‐induced increases in both the magnitude and frequency of floods. However, a detailed understanding of flood seasonality across these regions, and how flood seasonality may have changed over the instrumental record, has not been established. The annual timing of river floods reflects the flood‐generating mechanisms operating in a basin, and many aquatic and riparian organisms are adapted to flood seasonality, as are human uses of river channels and flood plains. Changes in flood seasonality may indicate changes in flood‐generating mechanisms, and their interactions, with important implications for habitats, flood plain infrastructure, and human communities. I applied a probabilistic method for identifying flood seasons at a monthly resolution for 90 Northeast U.S. watersheds with natural, or near‐natural, flood‐generating conditions. Historical trends in flood seasonality were also investigated. Analyses were based on peaks‐over‐threshold flood records that have, on average, 85 years of data and three peaks per year—thus providing more information about flood seasonality than annual maximums. The results show rich detail about annual flood timing across the region with each site having a unique pattern of monthly flood occurrence. However, a much smaller number of dominant seasonal patterns emerged when contiguous flood‐rich months were classified into commonly recognized seasons (e.g., Mar–May, spring). The dominant seasonal patterns identified by manual classification were corroborated by unsupervised classification methods (i.e., cluster analyses). Trend analyses indicated that the annual timing of flood‐rich seasons has generally not shifted over the period of record, but 65 sites with data from 1941 to 2013 revealed increased numbers of June–October floods—a trend driving previously documented increases in Northeast U.S. flood counts per year. These months have been historically flood‐poor at the sites examined, so warm‐season flood potential has increased with possible implications for aquatic and riparian organisms.     

Understanding coastal wetland hydrology with a new regional‐scale,process‐based hydrological model

Coastal wetlands represent an ecotone between ocean and terrestrial ecosystems, providing important services, including flood mitigation, fresh water supply, erosion control, carbon sequestration, and wildlife habitat. The environmental setting of a wetland and the hydrological connectivity between a wetland and adjacent terrestrial and aquatic systems together determine wetland hydrology. Yet little is known about regional‐scale hydrological interactions among uplands, coastal wetlands, and coastal processes, such as tides, sea level rise, and saltwater intrusion, which together control the dynamics of wetland hydrology. This study presents a new regional‐scale, physically based, distributed wetland hydrological model, PIHM‐Wetland, which integrates the surface and subsurface hydrology with coastal processes and accounts for the influence of wetland inundation on energy budgets and evapotranspiration (ET). The model was validated using in situ hydro‐meteorological measurements and Moderate Resolution Imaging Spectroradiometer (MODIS) ET data for a forested and herbaceous wetland in North Carolina, USA, which confirmed that the model accurately represents the major wetland hydrological behaviours. Modelling results indicate that topographic gradient is a primary control of groundwater flow direction in adjacent uplands. However, seasonal climate patterns become the dominant control of groundwater flow at lower coastal plain and land–ocean interface. We found that coastal processes largely influence groundwater table (GWT) dynamics in the coastal zone, 300 to 800 m from the coastline in our study area. Among all the coastal processes, tides are the dominant control on GWT variation. Because of inundation, forested and herbaceous wetlands absorb an additional 6% and 10%, respectively, of shortwave radiation annually, resulting in a significant increase in ET. Inundation alters ET partitioning through canopy evaporation, transpiration, and soil evaporation, the effect of which is stronger in cool seasons than in warm seasons. The PIHM‐Wetland model provides a new tool that improves the understanding of wetland hydrological processes on a regional scale. Insights from this modelling study provide benchmarks for future research on the effects of sea level rise and climate change on coastal wetland functions and services.     

2015年湖南冬汛成因分析

本文基于气象观测资料、再分析资料和国家气候中心提供的百项气候系统指数集,利用气候事件机理诊断和气候统计等方法,重点从降水背景、大尺度环流异常及外强迫因子对气候异常影响,分析2015 年湖南罕见冬汛及其成因机制,本文对2015年湖南冬汛及其可能成因进行了分析,结果表明：（1）2015年11月湖南省平均降水量偏多1.6倍,为1961年以来同期第一高位,其中湘东南部分地区降水量超过250 mm,出现气象洪涝。（2）在湖南11月降水处于偏多的年代际背景下,大气环流异常是导致湖南发生冬汛的最直接的原因,2015年11月西太平洋副热带高压偏强、偏西,引导来自印度洋、太平洋地区水汽向东亚地区输送,加上西路冷空气影响导致11月降水异常偏多。（3）在PDO暖位相时发生的El Ni〖AKn~D〗o事件可能是湖南降水异常的重要外强迫条件,赤道中东太平洋和印度洋海表温度异常偏高,导致该区域上空出现强的异常上升运动,而在海洋性大陆区域上空出现了一个异常下沉气流区,这有利于西太平洋副热带高压的加强、西伸,在东亚低纬地区上空出现异常下沉气流区,中纬地区上空出现异常上升气流区,造成该区域强烈的异常辐合,导致该地区持续阴雨天气。     

Dynamic variation of ambient shear stress field before and after three strong earthquakes in Yunnan

IntroductionThecrustaltectonicmovementisacomplicatedevolutionprocesswithtimeandspace.Spatially,themovementofcrustaltectoniciscloselyrelatedtotheinter-movementandinteractionofmulti-leveledcrustalblocksinacertainregionandtheirborderfaults.Temporally,themovementiscloselyrelatedtothatofmulti-leveledcrustalblocksandtimesequencedevelopmentofinteraction.Anearthquakeoccurrenceistheresultofsuddenruptureofcrustmediaundertheactionoftectonicstressfield,isalsoacomplicatedprocessinnercrust.Duetotheobviousi…