Calibration method affects the measured δ2H and δ18O in soil water by direct H2Oliquid–H2Ovapour equilibration with laser spectroscopy     

Hongxiu Wang  Bingcheng Si  Dyan Pratt  Han Li  Xiaojun Ma 《水文研究》2020,34(2):506-516

The direct H₂O_liquid–H₂O_vapour equilibration method utilizing laser spectroscopy (DVE-LS) is a way to measure soil pore water stable isotopes. Various equilibration times and calibration methods have been used in DVE-LS. Yet little is known about their effects on the accuracy of the obtained isotope values. The objective of this study was to evaluate how equilibration time and calibration methods affect the accuracy of DVE-LS. We did both spiking and field soil experiments. For the spiking experiment, we applied DVE-LS to four soils of different textures, each of which was subjected to five water contents and six equilibration times. For the field soil experiment, we applied three calibration methods for DVE-LS to two field soil profiles, and the results were compared with cryogenic vacuum distillation (CVD)-LS. Results showed that DVE-LS demonstrated higher δ²H and δ¹⁸O as equilibration time increased, but 12 to 24 hr could be used as optimal equilibration time. For field soil samples, DVE-LS with liquid waters as standards led to significantly higher δ²H and δ¹⁸O than CVD-LS, with root mean square error (RMSE) of 8.06‰ for δ²H and 0.98‰ for δ¹⁸O. Calibration with soil texture reduced RMSE to 3.53‰ and 0.72‰ for δ²H and δ¹⁸O, respectively. Further, calibration with both soil texture and water content decreased RMSE to 3.10‰ for δ²H and 0.73‰ for δ¹⁸O. Our findings conclude that the calibration method applied may affect the measured soil water isotope values from DVE-LS.  相似文献   

井筒电加热改善水平井蒸汽吞吐效果机理实验     

吴永彬  吕柏林  杜宣  卢迎波  蒋有伟  邢向荣 《现代地质》2021,35(4):1136-1146

针对稠油水平井蒸汽吞吐面临入井渗流阻力大、产量水平低、吞吐递减率高、采收率偏低等问题,提出了电加热辅助水平井蒸汽吞吐方法。首先根据水平井蒸汽吞吐过程中的电加热与蒸汽复合传热特征,建立了电加热辅助蒸汽吞吐三个阶段的(注汽阶段、焖井阶段、生产阶段)储层升温解析模型,在此基础上,设计并开展了电加热辅助蒸汽吞吐和常规水平井吞吐的宏观比例物理模拟对比实验,通过实验验证了解析公式,揭示电加热改善水平井吞吐效果关键机理,并利用实际典型井模型进行了潜力预测。结果表明:电加热协同蒸汽吞吐,具有注蒸汽阶段实现水平段均匀加热升温、焖井阶段持续热补偿加热近井地带、生产阶段降低原油入井渗流阻力并提高吞吐产量的关键机理。典型井组预测电加热辅助水平井吞吐可提高吞吐采收率9.4%,油汽比从0.14提高到0.23,在水平井蒸汽吞吐油藏具有重要应用潜力。  相似文献   

Preparation and Measurement of Cassiterite for Sn Isotope Analysis          下载免费PDF全文

Ryan Mathur  Wayne Powell  Andrea Mason  Linda Godfrey  Junming Yao  Mark E. Baker 《Geostandards and Geoanalytical Research》2017,41(4):701-707

Increased interest in the fractionation of Sn isotopes has led to the development of several techniques for preparing cassiterite (SnO₂, the primary ore of Sn) for isotopic analysis. Two distinct methods have been applied in recent isotopic studies of cassiterite: (a) reduction to tin metal with potassium cyanide (KCN) at high temperature (800 °C), with subsequent dissolution in HCl, and (b) reduction to a Sn solution with hydriodic acid (HI) at low temperature (100 °C). This study compares the effectiveness and accuracy of these two methods and contributes additional methodological details. The KCN method consistently yielded more Sn (> 70% in comparison with < 5%), does not appear to fractionate Sn isotopes at high temperatures over a 2‐hour period and produced consistent Sn isotope values at flux mass ratios of ≥ 4:1 (flux to mineral) with a minimum reduction time of 40 min. By means of a distillation experiment, it was demonstrated that HI could volatilise Sn, explaining the consistently low yields by this method. Furthermore, the distillation generated Sn vapour, which is up to 0.38‰ per mass unit different from the starting material, the largest induced Sn fractionation reported to date. Accordingly, the HI method is not recommended for cassiterite preparation for Sn isotopic analysis.  相似文献   

Heat calculation and numerical simulation in steam mining of permafrost gas hydrate          下载免费PDF全文

LI Bing  SUN Youhong  GUO Wei  LI Kuan 《世界地质(英文版)》2012,15(2):135-139

Steam mining method was injecting hot steam into the borehole to heat the hydrate strata at the same time of depressurization mining,which could promote further decomposition and expand mining areas of gas hydrate. Steam heat calculation would provide the basis for the design of heating device and the choice of the field test parameters. There were piping heat loss in the process of mining. The heat transfer of steam flowing in the pipe was steady,so the heat loss could be obtained easily by formula calculation. The power of stratum heating should be determined by numerical simulation for the process of heating was dynamic and the equations were usually nonlinear. The selected mining conditions were 500-millimeter mining radius,10 centigrade mining temperature and 180 centigrade steam temperature. Heat loss and best heating power,obtained by formula calculation and numerical simulation,were 21. 35 W/m and 20 kW.  相似文献   

基于循环注蒸气和烟气激励的海上稠油开采技术   总被引：1，自引：1，他引：0  

杨海林  钟立国 《东北石油大学学报》2013,(1):78-84,96,9,10

通过实验和油藏数值模拟,研究循环注蒸气和烟气激励的加热降黏、气体溶解降黏、气体扩大加热腔与减少热损失、蒸气与气体协同增产效应等开采机理,优化注入蒸气和烟气温度、烟气蒸气体积比、周期蒸气和气体注入量等参数,建议注入蒸气与烟气的温度高于300℃,在大气压下烟气蒸气体积比为0.4～0.6.在渤海稠油油田开展4口井循环注蒸气和烟气激励开采的现场试验.结果表明,循环注蒸气和烟气激励开采后稠油井平均日产油量达到冷采的3倍以上,最高日产油量超过100m3,周期产油量达到1.0×104 m3左右.基于循环注蒸气和烟气激励的海上开采稠油技术可以提高海上稠油开采速度和采收率,有潜力成为未来海上稠油油田的主要热采开发方式.  相似文献   

HD-1注汽井新型防砂材料的研究与应用     

沈朝霞  梁富春  高成元  刁俊西  孙理达 《海洋地质译丛》2010,(3):61-63

孤岛油田属稠油疏松砂岩油藏,生产过程中油井出砂严重,现有的涂敷砂人工井壁防砂注蒸汽后强度较低,造成防砂成功率低,注汽后高强度采液生产周期较短。为此,通过室内试验,优选出耐高温树脂、高强度骨架颗粒、偶联剂、固化剂,进行室内配方优化试验,评价固结体耐高温性能,测定其渗透率,研制出一种适用于疏松砂岩油藏注蒸汽热采井的HD-1注汽井新型防砂材料。在孤岛油田稠油注蒸汽热采区共试验72口井,成功率为91.0%,截止目前,累计产油为121 572 t,单井平均有效期为233 d。现场应用表明：HD-1注汽井新型防砂材料耐高温、强度高,防砂成功率高,有效期长,能够有效改善注蒸汽热采井的防砂效果。  相似文献   

膜蒸馏处理乳化油废水的实验研究     

王斯佳  蔡蕊  孙求实  袁文真  吕颖 《世界地质》2009,28(2):261-264

采用自制的中空纤维膜蒸馏组件对模拟的乳化油废水进行膜蒸馏处理研究, 分析了料液的浓度、流速、温度和处理时间等因素对膜通量及去除率的影响。实验结果表明: 在料液温度为50℃、流速为14 mL /min、乳化油浓度为500 mg/L 的条件下, 运行1 h后乳化油膜通量为21.20 g/m2 ·h, 去除率> 70%; 运行5 h后膜通量下降为5.141 g/m2 ·h, 去除率> 90%。  相似文献   

区域成矿流体的形成与演化   总被引：6，自引：0，他引：6  

肖荣阁  原振雷  刘敬党  费红彩  葛振华  张明燕 《地学前缘》2004,11(2):461-469

成矿流体是富含挥发份、碱金属的含矿卤水 ,其中碱金属来源于岩浆热液、变质热液、海水及通过水岩作用从岩石中萃取等 ;而挥发份来源于地幔、水岩作用与有机质分解作用。成矿流体中的硫也是多来源的 ,硫的活度与氧逸度有关 ,高温还原环境H2 S的活度降低 ;成矿流体的同位素分馏与水岩作用强度有关 ,控制同位素分馏的基本因素是温度及水岩比值。根据成矿流体的成分及物理化学性质 ,可以分类为高温硅钾卤水、中温碳酸盐卤水及低温硫酸盐型卤水。成矿流体没有固定的来源 ,在一定地质条件下 ,任何来源的热水流体都可以形成成矿流体。控制成矿流体形成的主要地质作用是岩浆作用、变质作用、地热增温作用及构造作用等。文中根据地质作用类型对区域地质流体进行划分 ,可分为岩浆作用区域成矿流体 (以高温硅钾卤水为主 ,可以有高温到中低温的流体分带 ) ,沉积作用区域成矿流体 (以中低温碳酸盐及硫酸盐型卤水为特征 ) ,大洋盆地区域成矿流体 (与岩浆岩区域成矿流体类似 ,有高温到低温的流体分带 )和变质作用区域成矿流体 (变质程度不同而有不同的流体类型混合 )。  相似文献   

Fractionation mechanism of stable isotope in evaporating water body     

ZHANG Xinping  TIAN Lide  LIU Jingmiao 《地理学报》2005,15(3):375-384

Under Rayleigh equilibrium condition, stable isotopic ratio in residual water increases with the decrease of the residual water proportion f exponentially, and the fractionation rate of stable isotopes is inversely proportional to temperature. However, under kinetic evaporation condition, the fractionation of stable isotopes is not only related to the phase temperature but also influenced by the atmospheric humidity and the mass exchange between liquid and vapor phases. The ratio δ in residual water will not change with f after undergoing evaporation of a long time for great relative humidity. The rate that the evaporating water body reaches isotopic steady state is mainly dependent on the relative humidity in atmosphere. The analysis shows that the actual mean linear variety rates, about -30.0, of the δ18O in residual water versus the residual water proportion at Nagqu and Amdo stations are consistent with the simulated process under temperature of 20 oC and relative humidity of 50%. The distillation line simulated under Rayleigh equilibrium condition is analogous to the global meteoric water line (MWL) as the temperature is about 20 oC. Under non-equilibrium condition, the slope and constant values of distillation line are directly proportional to temperature and relative humidity. According to the basic data, the simulated distillation line is very consistent with the actual distillation line of Qinghai Lake.  相似文献   

Discharge and suspended sediment dynamics during two jökulhlaups in the Skaftá river,Iceland     

Gareth H. Old  Damian M. Lawler  rni Snorrason 《地球表面变化过程与地形》2005,30(11):1441-1460

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