基于水平集方法的低渗砂岩数字岩心气水两相渗流模拟

低渗致密砂岩气藏孔喉结构复杂,气水流动及分布规律表征难,常规岩心实验精细刻画困难。基于真实低渗砂岩岩心,利用Micro-CT扫描技术构建储层三维数字岩心,提取连通孔隙结构并建立非结构化四面体网格模型。结合水平集法与N-S方程,建立气水两相流数学模型并利用有限元方法进行求解,研究低渗砂岩气水两相流动中的水驱气过程、残余气分布特征、岩石润湿性对两相流的影响以及并联通道中的窜流特征。结果表明：利用水平集方法能清晰地观察到气水两相分布特征与驱替前缘的运移规律;岩石润湿性对两相流过程影响较大,水湿条件下采出程度更高;并联通道中的窜流现象明显,大通道中水相优先突破并形成优势流动通道,狭小通道中的流动受毛管现象影响,存在较大的附加阻力。     

黄河三角洲粉质土的动模量和阻尼比试验研究

结合室内共振柱和动三轴实验,对黄河三角洲饱和原状粉质土体(粉土、粉砂、粉质粘土)动模量和阻尼比的影响因素和发展规律进行了详细的研究。研究表明,在粉粒和粘粒含量对动模量的共同影响中,粉粒含量起着举足起重的作用;侧限压力对归一化剪模比和阻尼比的影响均较显著,相比粘粒含量的影响不大。通过与Seed建议的砂土及饱和粘土的G/Gmax~γ曲线和λ~γ曲线进行对比,结果显示研究区的粉质土相比一般的砂土和饱和粘土而言,其动力变形特性更接近于砂土,但是与砂土也存在着非常明显的差异;其发展规律与其他地区沉积粉质土也较为不同,具有明显的区域性。采用修正了的Hard in-D rnevich模型和对数模型分别对G/Gmax~γ曲线和λ~γ曲线进行拟合,给出了三类粉质土的归一化动力变形G/Gmax~γ/γr关系曲线,对模型中有关参数的影响因素做了初步的探讨。     

Lattice-Boltzmann simulations of flow through Fontainebleau sandstone

We report preliminary results from simulations of single-phase and two-phase flow through three-dimensional tomographic reconstructions of Fontainebleau sandstone. The simulations are performed with the lattice-Boltzmann method, a variant of lattice-gas cellular-automation models of fluid mechanics. Simulations of single-phase flow on a sample of linear size 0.2 cm yield a calculated permeability in the range 1.0–1.5 darcys, depending on direction, which compares qualitatively well with a laboratory measurement of 1.3 darcys on a sample approximately an order of magnitude larger. The sensitivity of permeability calculations to sample size, grid resolution, and choice of model parameters is quantified empirically. We also present a qualitative study of immiscible two-phase flow in a sample of linear size 0.05 cm; simulations of both drainage and imbibition are presented.     

Process Based Reconstruction of Sandstones and Prediction of Transport Properties

We present a process based method for reconstructing the full three-dimensional microstructure of sandstones. The method utilizes petrographical information obtained from two-dimensional thin sections to stochastically model the results of the main sandstone forming processes – sedimentation, compaction, and diagenesis. We apply the method to generate Fontainebleau sandstone and compare quantitatively the reconstructed microstructure with microtomographic images of the actual sandstone. The comparison shows that the process based reconstruction reproduces adequately important intrinsic properties of the actual sandstone, such as the degree of connectivity, the specific internal surface, and the two-point correlation function. A statistical reconstruction of Fontainebleau sandstone that matches the porosity and two-point correlation function of the microtomography data differs strongly from the actual sandstone in its connectivity properties. Transport properties of the samples are determined by solving numerically the local equations governing the transport. Computed permeabilities and formation factors of process based reconstructions of Fontainebleau sandstone compare well with experimental measurements over a wide range of porosity.     

基于现场光谱的潮滩表层沉积物叶绿素-a含量遥感模式

提出了一种可实现潮滩表层叶绿素的现场快速、无损的光学检测方法。利用反射率光谱对我国潮滩表层沉积物叶绿素-a浓度进行了观测试验。基于高光谱650,675及700nm各波段的反射率,提出了用于叶绿素浓度反演的归一化底栖微藻差异指数(NDI-MPB)、及可消除呈直线或近似直线变化的背景噪声光谱的反射谷深度(T-depth)模型。研究结果表明,NDI-MPB指数与表层沉积物(3mm)中的叶绿素-a浓度(2.22～49.36mg.m-2)有极好的线性相关性(r>0.99);以叶绿素-a浓度表征底栖微型藻类生物量,NDI-MPB可用于潮滩表层底栖微型藻类生物量的遥感监测。     

Coagulation effect and floc properties of polyferric silicate sulphate and polyferric sulphate in the Yellow River water treatment

Two inorganic polymer coagulants,polyferric silicate sulphate(PFSS) and polyferric sulphate(PFS),were comparatively evaluated in the Yellow River water treatment.The removal efficiency of turbidity and UV254 were investigated,and the zeta potential was measured.An online laser scatter instrument was used to determine the size distribution of flocs formed in the coagulation processes.Compared with PFS,PFSS forms flocs with higher growth rates and larger sizes.The formed flocs were exposed to a series of shea...     

间苯二酚黄-CTAB-核酸共振光散射体系的研究及应用

在PH3．1－3．5的柠檬酸－NaOH介质中，核酸（fsDNA，yRNA）与阳离子表面活剂CTAB对阴离子染料间苯二酚黄的共振黄的共振光散射光谱有 协同增强作用，在最佳实验条件下，fsDNA,yRNA的线性范围均为0－4μg/mL，检出限分别为8．1ng/mL和7.2ng/mL。据此建立了一种测定核酸的新方法。     

南黄海表层沉积物稀土元素分布与物源关系

对南黄海295个表层沉积物样品稀土元素的电感耦合等离子体质谱法分析,结果表明,南黄海表层沉积物稀土元素平均含量为188.39μg.g-1,稀土富集与重矿物有密切关系;稀土元素的球粒陨石配分模式均呈现Eu负异常,模式具负斜率,表明表层沉积物物质主要来源于大陆地壳。从稀土元素地球化学特征的区域变化来看,南黄海东部沉积物来源于朝鲜半岛,西部沉积物来源于黄河和长江物质输入,中部细粒沉积物主要与黄河及长江物质东南、东北扩散有关,东南部为朝鲜半岛及黄河、长江物质共同作用的结果。     

Processing and structure of gallium nitride—gallium oxide platelet nanostructures

Gallium nitride-gallium oxide structures were formed by heat-treating gallium nitride (GaN) powders in several gas environments at temperatures from 400°C to 900°C. The platelet nanostructured particles were examined at several stages of oxidation by microscopic, structural, chemical and optical spectroscopic techniques. Particle morphology, nanophase characterization and photoluminescence data showed that the oxide layers passivate the GaN platelets surfaces and significantly reduce the yellow emission while enhancing near band-edge emission.     

系数倍率导数光谱法定量测定纤维上染料

本文介绍了用系数倍率导数光谱法同时测定黄棕色涤纶上的分散黄ＲＧＦＬ，分散棕２ＲＬ，分散红Ｓ－ＢＷＦＬ的配比。这三种染料吸收峰重叠大，用该法可以完全消除彼此的干扰而不用分离，测得三种染料的配比与工艺配方中的比例一致，结果准确，可靠，回收率较好。这个方法操作简便，快速，可用于纵上染料的测定。