Water–rock interaction during the process of steam stimulation exploitation of viscous crude oil in Liaohe Shuguang Oil Field, Liaoning, China

In the process of steam stimulation exploitation of viscous crude oil, the injected water, at high temperature and under high pressure, reacts intensively with the host rock. This kind of water–rock interaction in Liaohe Shuguang Oil Field was studied on the basis of analysis of water composition changes, laboratory experiments, mineral saturation indices analysis, and mass balance calculation. Compared with the injected water, the changes of the composition of discharged water are mainly the distinct decrease of pH, Na⁺, SiO₂ and Cl⁻, as well as the increase of K⁺, Ca²⁺, Mg²⁺, SO ₄ ²⁻ and HCO ₃ ⁻ . Laboratory experiments under field conditions showed: the dissolution sequence of minerals quantitatively is quartz>potassium feldspar>albite, and the main change of clay minerals is the conversion of kaolinite to analcime. Mass balance calculation indicated during the process of steam stimulation, large quantities of analcime are precipitated with the dissolution of large amounts of quartz, kaolinite, potassium feldspar, and CO₂. These results correlated very well with the experimental results. The calculated results of Liaohe Shuguang Oil Field showed that during the steam stimulation for viscous crude oil, the amounts of minerals dissolved (precipitated) are huge. To control the clogging of pore spaces of oil reservoirs, increased study of water–rock interaction is needed.     

湿地生态系统碳循环过程及碳动态模型

从地上、地下有机物质生产对湿地碳输入的贡献,湿地土壤碳库以及土地利用变化对湿地土壤碳库和碳排放的影响,甲烷排放和可溶性有机碳输出以及影响因子,湿地生态系统碳循环动态模型4个方面对湿地生态系统碳循环国内外研究进展和研究成果进行综述、分析,提出了我国亚热带区域天然湿地碳循环研究的主要热点和方向:⑴沿海湿地碳库估算及土地利用转化对土壤碳库和温室气体排放的影响;⑵酸沉降对于我国东南沿海低纬度地区湿地甲烷排放的影响;⑶沿海湿地生态系统碳循环动态模型的应用与开发;⑷湿地系统可溶性有机碳的输出机理探讨.     

Sources of Sediment in Lake Pepin on the Upper Mississippi River in Response to Holocene Climatic Changes

Sediments from Lake Pepin on the Mississippi River, southeastern Minnesota, are used as provenance tracers to assess variations in hydrology and sediment-transport during the middle Holocene. Three rivers contribute sediment to Lake Pepin, and each catchment is characterized by a distinctly different geologic terrain. The geochemical fingerprint for each drainage basin was determined from the elemental composition of heavy minerals in the silt-sized fraction of modern sediment samples. Down-core elemental abundances were compared with these fingerprints by use of a chemical-mass-balance model that apportions sediment to the source areas. We observed a decreased contribution from the Minnesota River during the interval ~6700–5500 ¹⁴C yr BP, which we attribute to decreased discharge of the Minnesota River, likely controlled by a combination of precipitation, snow melt, and groundwater input to the river. This hydrologic condition coincides with the mid-Holocene prairie period recorded by fossil pollen data. The occurrence of this feature in a proxy record for hydrologic variations supports the hypothesis that the mid-Holocene prairie period reflects drier conditions than before or after in midwestern North America.     

A geochronological approach to understanding the role of solar activity on Holocene glacier length variability in the Swiss Alps

We present a radiocarbon data set of 71 samples of wood and peat material that melted out or sheared out from underneath eight presentday mid‐latitude glaciers in the Central Swiss Alps. Results indicated that in the past several glaciers have been repeatedly less extensive than they were in the 1990s. The periods when glaciers had a smaller volume and shorter length persisted between 320 and 2500 years. This data set provides greater insight into glacier variability than previously possible, especially for the early and middle Holocene. The radiocarbon‐dated periods defined with less extensive glaciers coincide with periods of reduced radio‐production, pointing to a connection between solar activity and glacier melting processes. Measured long‐term series of glacier length variations show significant correlation with the total solar irradiance. Incoming solar irradiance and changing albedo can account for a direct forcing of the glacier mass balances. Long‐term investigations of atmospheric processes that are in interaction with changing solar activity are needed in order to understand the feedback mechanisms with glacier mass balances.     

数据备份服务器备份性能分析

针对数据备份服务器备份性能优化问题，分别对实时数据存储与历史数据备份之间的关系、数据备份服务器所备份的数据类型非唯一性、客户数量对备份服务器备份效率的影响三方面进行初步的测试与分析，提出了通过优化数据块的选取、优化数据采集方式、优化备份策略提高备份服务器备份效率的基本方法。     

玛纳斯河一级电站引水渠沿线提取地下水进行融冰的可行性研究

通过对向斜洼地含水层水文地质特征的勘探及研究,对研究区的水文地质边界条件进行了概化,并用水均衡法估算了地下水资源量,对拟建一级电站引水渠沿线提取地下水进行融冰的可行性进行了研究,并提出了取水方案.     

内陆盆地的盐分布与平衡分析研究

在总结已有研究成果和系统分析水文、土壤、灌溉、水盐监测资料的基础上,应用系统分析方法、水盐运移理论和水盐平衡原理,通过对盆地、流域、灌区、农田和土壤剖面等不同层次盐分分布与盐平衡分析计算,分析了内陆盆地不同层次的“干排盐”形成与特征,认为干排盐是必不可少的,必须系统地考虑不同层次干排盐出路与动力条件,才能有效地治理灌区盐渍化问题。     

水稻灌区节水灌溉的尺度效应

探讨了节水灌溉尺度问题,指出产生节水灌溉尺度现象的原因是由于灌溉过程中回归水的重复利用.结合漳河灌区的实际,讨论了水稻种植区在不同尺度下的水平衡要素及其在节水尺度效应中的作用;说明随尺度的增大,水平衡过程变得复杂化,节水尺度效应现象也更突出.利用漳河灌区田间试验数据和灌区长系列的历史资料,分别从田间、中等、灌溉干渠和灌区共四个尺度,定量地分析了水稻节水灌溉对水分生产率以及水分利用率的影响.结果表明,节水灌溉技术的采用不仅可以提高田间尺度的灌溉水分生产率,也促进了漳河灌区灌溉水分生产率的整体上升.     

土壤热异常对地表能量平衡影响初探

将来自土壤深部的热通量引入off line的陆面过程模式 (NCAR—LSM ) ,通过长达 2a的数值试验对比分析了它对各层次土壤温度和地表能量平衡的影响。　　在土壤底部引入 5W /m2 的热通量使底层土壤显著升温 ,但升温随着接近表层而迅速衰减。积分 3个月后 ,由地下进入地表的热流量增幅可达 1W/m2 以上 ,并持续增大到 5W /m2 ,地表最大升温约 0 .5K ,同时地表感热、蒸发潜热及长波辐射通量均有 1W /m2 左右的正异常 ;若将土壤热传导系数放大一个量级以加速热量交换 ,则地表升温提高到 1K以上 ,长波辐射增加 3W /m2 以上 ,超过了气溶胶全球平均的辐射效应。结果表明 :一定量值的土壤热异常对地表能量平衡和短期气候变化 (10 -1～ 10 1a)有着不可忽略的影响。同时 ,深入的资料分析、完善的陆面过程模式以及它与大气模式的耦合试验也是亟待进行的相关工作。     

东南极Lambert冰川-Amery冰架系统平衡通量分布的计算

通过对Lambert冰川盆地(LGB)考察路线上约1 700 km长的LGB剖面和距冰架末端约50 km、长150 km的A剖面, 分别利用GPS冰流速值及雷达测厚值进行冰通量的计算得出:每年流过LGB剖面的冰通量为43.95 Gta-1, 而通过A剖面的冰通量仅为26. 42 Gt*a-1, Amery冰架底部净融化量为7.8 Gt*a-1. 整个Lambert冰川-Amery冰架系统(LAS)地区的表面净物质平衡总量约为90 Gt*a-1; LGB地区的表面净物质平衡总量为46 Gt*a-1. 通过分析得出, 整个LAS地区及LGB地区均处于物质正平衡状态, 而LAS流域的上游区域S'则处于物质负平衡状态.