共查询到14条相似文献,搜索用时 156 毫秒
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引入分形理论,建立考虑低速非达西效应的分形三重介质缝洞型油藏数学模型,通过Laplace变换及Stehfest数值反演方法求出井底压力,借助Matlab编程绘制压力动态曲线,划分渗流阶段,分析渗流规律,进行非线性参数敏感性分析.最后结合实际算例,验证模型的正确性.结果表明:分形三重介质油藏渗流过程分为早期纯井储,过渡流,缝洞窜流,拟径向流,基质与溶洞、裂缝窜流及总体径向流6个渗流阶段;低速非达西效应对渗流的影响随时间的推移逐渐增大;启动压力梯度越大,总径向流阶段压力动态曲线上翘幅度越大;分形系数影响整个渗流过程,随着分形系数的增大,裂缝迂曲程度随之增大,致使渗流阻力增加,引起压力动态曲线整体上移幅度增大. 相似文献
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针对稠油非牛顿特征,在Bingham流体渗流方程基础上,通过对动半径和粘度进行表征,建立同时考虑启动压力梯度、动半径变化和粘度变化的非牛顿稠油不稳定渗流数学模型,完善Bingham型稠油渗流数学模型.通过空间、时间离散差分及Matlab数值计算,得到非牛顿稠油非稳态渗流地层压力分布.结果表明,相同产量下,随启动压力梯度增大,动半径向井方向移动;启动压力梯度越大,压降曲线越陡,相应近井压降越大;相同启动压力梯度下,产量越大,不同吞吐周期压力差距越大.将半径和粘度动态变化相结合,弥补了现行非牛顿稠油渗流数学模型的-个缺陷. 相似文献
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考虑油水两相、生产历史、油藏平面非均质性、井筒储存和表皮效应等因素,建立了生产历史阶段聚合物驱数学模型和不稳定试井阶段的流线模型,用流管法对解释模型进行了数值求解.研究表明:随着油水粘度比的增大,压力及压力导数曲线向上平移,随着生产时间的增加,储层的有效渗透率降低,当高渗透条带沿主流线方向分布时,注水井压降导数曲线反映不出油水前缘的影响,而随着聚合物注入浓度的增大,压力导数曲线下凹出现的越来越早. 相似文献
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基于传递熵方法, 分析Lorenz系统x, y, z三个分量之间的信息传输方向, 并应用温差与垂直速度的再分析资料对Walker环流进行分析. 研究结果表明: 1) 对于Lorenz系统而言, x与y分量之间, y是信息源, x是信息汇; y与z之间, y是信息源, z是信息汇; x与z分量之间的信息传递方向依赖于控制参数r; 且净信息传输的方向不随初值不同而改变; 2)在西太平洋地区, 温差对垂直速度的净信息输送占主导地位, 而赤道东太平洋地区则为垂直速度对温差的净信息输送占主导地位, 这与Walker环流物理机制是一致的, 且海陆热力差异对温差与垂直速度之间的信息输送影响较大; 3)冬季是温差与垂直速度之间的信息输送最强季节, 夏季和秋季次之, 春季最弱, 这可能是存在春季预报障碍的原因之一. 以上结果表明, 传递熵在气象领域有广阔的应用前景, 是测量动力学系统信息传递方向的一种有效方法和工具.
关键词:
传递熵
信息传输
Lorenz系统
Walker环流 相似文献
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The nucleation mechanism to predict coercivity values in melt-spun exchange-coupled (Nd1−xPrx)yFe94−yB6 alloys for various Nd:Pr ratios x, and Fe:RE ratios y, was tested using the dependence of the anisotropy constant K1 on Pr content x for the minimum nucleation field HNmin in the modified Brown's equation. Very good agreement was found between experimental data and theoretical values, confirming the predominance of the nucleation of reverse domains over the wall pinning process in the coercivity mechanism of melt spun REFeB alloys. 相似文献
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多点边值问题的插值矩阵法及误差分析 总被引:1,自引:0,他引:1
插值矩阵法是求解多点边值问题的数值法。本文给出的该法的误差分析,论证了插值矩阵法解得的y(x),y'(x),…,y(m)(x)有相同的精度,并对二阶方程,给出该法的稳定性证明和收敛阶。 相似文献
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E.F. Pedroso C.L.M. Pereira H.F. dos Santos L.F.C. de Oliveira W.C. Nunes M. Knobel H.O. Stumpf 《Journal of magnetism and magnetic materials》2008,320(14):e200-e203
The synthesis of one-dimensional, molecule-based magnets and the investigation of their structure and physical properties are described. The one-dimensional CoCu(opba) system, where opba [ortho-phenylenebis(oxamato)] bridges the metal ions resulted in antiferromagnetic coupling, and was studied by insertion of electron donating and electron withdrawing groups in the organic ligands’ aromatic rings. In order to verify the influence of these modifications, three compounds of the formula [CoCu(opba-xy)], where x=y=CH3 (compound 1), x=y=Cl (compound 2), x=H and y=NO2 (compound 3) are described. The electronic structure of the oxamato bridge group has been studied using calculations at the density functional theory (DFT) level for [Cu(opba-xy)]2− building blocks. Magnetic measurements in polycrystalline samples showed ferrimagnetic behavior for the three compounds. Least-squares fits of the experimental data indicate antiferromagnetic couplings JCoCu of −35.0, −32.9 and −24.2 cm−1 for 1, 2 and 3, respectively. 相似文献
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A. V. Radyushkin 《Physics letters. [Part B]》1996,380(3-4):417-425
I outline a perturbative QCD approach to the analysis of the deeply virtual Compton scattering process γ*p → γp′ in the limit of vanishing momentum transfer t = (p′ − p)2. The DVCS amplitude in this limit exhibits a scaling behavior described by two-argument distributions F(x,y) which specify the fractions of the initial momentum p and the momentum transfer r ≡ p′ − p carried by the constituents of the nucleon. The kernel R(x,y;ξ,η) governing the evolution of the non-forward distributions F(x,y) has a remarkable property: it produces the GLAPD evolution kernel P(x/ξ) when integrated over y and reduces to the Brodsky-Lepage evolution kernel V(y,η) after the x-integration. This property is used to construct the solution of the one-loop evolution equation for the flavor non-singlet part of the non-forward quark distribution. 相似文献
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O. Kalogirou
D. Samaras
A. C. Stergiou
《Journal of magnetism and magnetic materials》1990,89(3):379-385Single crystals of Ba, Sr M-type hexagonal ferrites were prepared by ion exchange in Ba, Sr containing molten salts from single crystals of β″ -ferrites. A fast diffusion of the divalent Ba2+, Sr2+ is observed leading to a non-stoichiometric M-type ferrite with chemical formula: Ba1+xFe10.5Co0.25O17+x (0 ≤ x ≤ 0.25). x depending on the exchange reaction time. Saturation magnetization ranges from 19 to 64 emu/g depending on exchange conditions. The Curie temperature is (470 ± 5)°C. An easy axis direction (Ms c) has been determined in all cases. The observed anisotropy is considerably lower than that of M ferrite. The calculated anisotropy constants are, in 106 erg/cm3, K1 = 0.8 and K2 = 1.0 at room temperature. 相似文献
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A Bi2V1 − x − yUxBiyO5.5 + 0.5x − y solid solution derived from Bi4V2O11 has been prepared and characterized with x up to 0.125 for y = 0. Partial substitution of U6+ for V5+ in Bi4V2O11 leads to the stabilization at room temperature of the high-oxide ion conducting γ-phase, in contrast with other M6+ dopants which stabilize the β-phase. The lower conductivity in U substituted system compared with BICUVOX.10 is attributed to its higher activation energy. Conductivity values and activation energies of the U substituted phases compare well with Bi2UO6. 相似文献
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An off-axis holographic system in the side-scattering mode has been studied, and the requirements of fringe resolution and film sensitivity associated with holographic imaging of side-scattering particles analysed. By assuming the Mie scattering model, the fringe distribution about the y-axis (perpendicular to the plane of incidence of the reference light) was found to be asymmetrical, with unevenly distributed spacing, that is narrower in one x direction but greater in the side that is close to the origin. It was demonstrated that commercially available holographic film was sufficient to resolve the fringe frequency over the entire area of the holographic plate, at 60 ° for z = 120 mm, and that images of particles as small as 20 μm could be recorded. Astigmatism was found to occur and be responsible for the distortions of the particle images. 相似文献
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Jamila Ghamri Herv Baussart Michel le Bras Jean-Marie Leroy 《Journal of Physics and Chemistry of Solids》1989,50(12):1237-1244
The mixed oxides BixEu1−xVO4 and BiyGd1−yVO4 crystallize in a zircon-type structure, for 0 <x < 0.6 and 0 < y < 0.64, and in a fergusonite-type structure, for 0.94 < x < 1 and 0.93 < y < 1. A process of competition between the dominant and the constrained effects of the lone-pair 6s2 of Bi3+ is discussed. The diffuse reflectance spectroscopic studies of these mixed oxides are presented. The observed broad bands are attributed to charge transfer processes and the sharp peaks in the BixEu1−xVO4 spectra are ascribed to intra-configurational 4f – 4ftransitions of the Eu3+ ion. The broad absorption shift in BiLnVO4 (Ln : Eu and Gd) compounds to the longer wavelengths range, when Bi is introduced in the LnVO4 lattice, is ascribed to charge transfer processes in a Bi-VO4 center and are interpreted assuming a Jahn-Teller effect in the excited state of Bi3+. The concept of an internal pressure of Bi3+ ions is also used to explain the broad A-band shifts. 相似文献