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431.
南极冰层取心钻探酯基钻井液抗低温性能试验 总被引:10,自引:0,他引:10
钻井液的选择是顺利进行极地科学钻探工程的关键技术之一。为寻找一种新型安全、环保的耐低温钻井液,笔者深入分析一元脂肪酸酯与二元脂肪酸酯分子结构特点,对三种不同混合酯的耐低温性能进行了试验研究,测试了三种混合酯的黏度与密度随温度的变化。试验发现,当温度下降时,混合酯的黏度都存在一个稠化温度,稠化温度的高低受酯的分子结构、分子量及分子间作用力的影响。混合酯的组成、分子结构及分子间作用力大小不影响密度随温度的变化关系,但对密度的大小与密度增加的速度影响较大。 相似文献
432.
《Geomechanics and Geoengineering》2013,8(1):59-69
Arid regions worldwide are plagued by collapsible soils. Collapsible soil is characterised by the sudden decrease in volume that occurs when it is subjected to inundation under constant stress. This volume change manifest itself as drastic and unpredicted foundation settlement, which may lead to further catastrophic failure of the supported structures. Collapse settlement is the term applied to the additional settlement of a foundation due to wetting of the underlying soils. The results of an experimental investigation of the effects of the saturation of soil with water, kerosene, and crude oil, and of the effects of the fluid head on the magnitude, degree, and rate of collapse of the underlying soil are presented in this paper. Soil erodibility is presented in terms of the applied hydraulic shear stress and the rate of erosion. The relationship between soil erosion and the magnitude and rate of collapse is examined. Empirical methods for the prediction of the magnitude and rate of collapse of a soil saturated with the test fluids and subjected to a hydraulic constant head are proposed. 相似文献
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对现行的全站仪加乘常数的计算方法进行了合理性分析,并对实测的数据和模拟的数据进行了计算。结果表明,现行的计算全站仪的加乘常数的方法是有缺陷的,需要进一步的完善。 相似文献
436.
Understanding petrographical, geochemical and electrical properties of rocks is essential for investigating minerals. This paper presents a study of the petrographical, geochemical and A.C. electrical properties of carbonate rock samples. The samples collected show six lithostratigraphic rock units. Electrical properties were measured using a non‐polarizing electrode at room temperature (~20°C) and a relative atmospheric humidity of ~50% by weight in the frequency range from 42 Hz to 5 MHz. The difference in electrical properties between the samples was attributed to the change in composition and texture between the samples. Electrical properties generally change with many factors (grain size, chemical composition, grain shape and facies). The dielectric constant decreases with frequency and increases with conductor composition. The conductivity increases with the increase of conductor paths between electrodes. Many parameters can contribute to the same result of the electrical properties. The main objective of the present study is to shed more light on the relation between the texture and geochemical composition of measured samples (carbonates that contain clays and quartz grains) through electrical laboratory measurements (conductivity and dielectric constant as a function of frequency). 相似文献
437.
Ling Man Tsang 《New Astronomy》2012,17(1):18-21
The spring constant of the earth is found to be 1.1 × 10−8/s2 which is based on the famous Pound and Rebka gravitational red-shift experimental data. The spring force, or so-called the fifth force of the earth is then known. This paper suggests how can NASA’s Lunar Reconnaissance Orbiter (LRO) projects verify the existence of the fifth force by simple free fall experiment without man-mission. Such a force, as we have predicted, should be the type of intermediate range. 相似文献
438.
黄土高原流域地下水更新时间估算(英文) 总被引:2,自引:0,他引:2
Groundwater residence time is an important indicator of hydrological cycle and essential for water resources development and utilization.In this paper,groundwater residence time in non-flood season,flood season and water year has been determined from daily streamflow hydrograph of ten hydrological stations in Wudinghe River Basin located in the middle reaches of the Yellow River Basin.Results have showed that:baseflow recession constant in Wudinghe River Basin ranges from 0.72 to 0.94 with a larger recessio... 相似文献
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饱和储层砂岩中流体粘度引起的超声波速度频散实验研究(英文) 总被引:8,自引:3,他引:5
在实验室对5块储层砂岩进行了模拟地层压力条件下的超声波速度测试。砂岩样品采自WXS凹陷的W地层,覆盖了从低到高的孔隙度和渗透率范围。实验选用了卤水和4种不同密度油作为孔隙流体,结合温度变化,实现了对流体粘度引致的速度频散研究。对实验结果的分析表明:(1)对于高孔隙度和渗透率的样品,无论是哪种流体饱和,观察到的超声波速度测试值和零频率Gassmann预测值的差异较小(约2-3%),基本上可以用Biot模型解释;对于中等孔隙度和渗透率的样品,低粘度流体(<约3mP?S)的频散效应也可以用Biot模型得到合理解释;(2)对于低、中孔隙度和渗透率样品,当流体粘度增加时,喷射流机制起主导作用,导致严重的速度频散(可达8%)。对储层砂岩的微裂隙纵横比进行了估计并用于喷射流特征频率的计算,当高于该特征频率时,Gassmann理论的假设条件受到破坏,实验室测得的高频速度不能直接用于地震低频条件下的W地层砂岩的Gassmann流体替换研究。 相似文献