杏六区薄差储层有效动用界限研究

大庆长垣内部油田已进入高含水期,目前的水驱开发对象已由中高渗透层逐渐转变为薄差储层,这类储层油藏地质条件复杂,开发效益较差,已探明的储量中却有数亿吨储量主要存在于低渗透的薄差储层中.由于其微观孔隙结构和物性特征与厚油层存在差异,有些物性较差的储层甚至无法动用.以大庆油田杏六区的薄差储层为研究对象,运用压力数法和非线性渗流指数法确定有效动用的渗透率下限,利用双管并联实验确定级差上限,结合核磁共振技术与压汞实验结果给出孔喉动用的下限,得出:杏六区薄差储层有效动用的渗透率下限为1×10~(-3)μm~2;级差上限为5;流动孔喉半径下限为0.288μm,该结果为薄差储层的有效开发提供了一定的参考和借鉴.     

Experimental study on the Karst area fracture zones of the synthesizing geophysical methods

岩溶地区地形、地质情况相对复杂,各种物探方法的应用都受到一定条件限制,进行岩溶断裂破碎带勘察时,应进行综合物探勘察,为设计和施工提供可靠的原始资料;本文采用综合物探方法对广州地铁九号线工程田美断裂进行探测,详细查明田美断裂的走向、破碎带宽度、构造破碎特征、断裂的性质、规模和产状等;同时辅以少量勘察验证孔施工对断裂做验证,以便有效地揭示断裂特征,通过实验取得较理想的成果,并意外地发现了田美断裂的次一级断裂。     

Crack-tip-opening displacement for four symmetrically situated cracks with coalesced interior yield zones

Crack-tip opening displacements are obtained for four collinear straight cracks, weakening an unbounded homogeneous and isotropic elastic-perfectly plastic plate. The cracks are so configured that two symmetrically situated and interiorly lying cracks are of equal-lengths. Other two exteriorly lying, collinear straight cracks (surrounding the interiorly lying straight cracks) are of mutually equal-lengths. Thus an exterior and an interior crack-set are symmetrically oriented with respect to the other interior–exterior collinear cracks-set configuration. Uniform constant load prescribed at remote boundary of the plate, opens the crack in self-similar fashion developing a strip-yield zone ahead each tip of the cracks. It is assumed that the strip-yield zone developed at each of interior tips of an exteriorly and interiorly lying crack-set configuration gets coalesced. The developed yield zones are subjected to normal cohesive yield stress to arrest the crack from further opening. The solution of the problem is obtained by superposing the solutions of the two auxiliary problems, appropriately derived from the given problem. Each of the auxiliary problems, in turn, is solved using complex variable technique. Expressions are derived for quantities of interest viz. crack-tip opening displacement (CTOD), length of each developed yield zone. The effect of applied load and closing load on the parameters CTOD and strip yield zone affecting the crack arrest is presented graphically and concluded.     

一维光子晶体非线性色散特性的分析

从无限周期一维光子晶体的色散关系和有限周期光子晶体的透射系数两个方面,对有限和无限周期光子晶体有效折射率的实部和虚部特性曲线分别进行了计算和分析.结果表明一维光子晶体的色散曲线与弹性电偶极子的经典色散曲线类似,在光子晶体的导带为正常色散,而在禁带呈现反常色散.并且用简约布里渊和扩展布里渊区色散曲线对文献报道中存在的两种矛盾的计算结果进行了理论的探讨.解释了导致对一维光子晶体有效折射率计算存在两种不同结果的原因.     

垂直入射弹性波在压电体单侧接触界面上的传播特性

弹性波与压电材料接触界面的相互作用问题是工程应用中常见而复杂的问题,入射波足够强会引起界面出现滑移和分离,但滑移和分离的边界未知,边界条件具有非线性特性。通过Fourier分析,将混合边值问题的求解转化为非线性代数方程,利用软件通过迭代修正的方法进行了求解;给出3种状态边界的求解,分析入射波强度、外加应力及电场对界面状态的影响,并对高频谐波的特性进行分析,通过实例对理论推导进行验证,结果显示:入射波强度、外加荷载和电场的大小及摩擦因数均会影响到界面,通过改变这些条件可以控制界面状态,另外检测高频谐波的信号也可以反映界面状态。     

基于等厚干涉的环形子孔径检测中环带参数的计算方法

环形子孔径拼接检测技术是一种利用小口径干涉仪实现对大口径非球面检测的有效方法。检测过程中,需要多次改变干涉仪同非球面镜之间的距离,以得到不同环带的干涉条纹。以等厚干涉为基础,建立了环带数学模型,仿真分析了各个环带的理论参数,以及干涉仪同非球面之间的理论距离。结果表明,该模型可用于环形子孔径拼接的仿真计算,对实际检测过程具有很好的指导作用。     

System zones in capillary zone electrophoresis: moving boundaries caused by freely migrating hydroxide ions

We present theoretical and experimental data indicating that anionic system zones (SZs), due to free migrating hydroxide anions, can be expected in background electrolytes (BGEs) with a low buffer capacity. In the system containing completely unbuffered BGEs the hydroxide ions derived from the sample start to migrate freely through the capillary tube with the mobility of single hydroxide ions and cause stepwise disturbances in the baseline of the detector trace. Remarkably, this type of SZs do not appear to contribute significantly to the electromigration dispersion (EMD) of the zones of the analytes.     

System eigenmobilities in zone electrophoresis: A general moving-boundary approach

System zones in capillary zone electrophoresis represent an important topic, very interesting from the theoretical point but also important for practice. This paper is aimed at contributing to the understanding of system zones as one of the very fundamental properties of electrophoretic systems, by developing an alternative approach to the so far used vector-matrix model of calculation of system mobilities (system eigenmobilities). The presented model is based on the solution of the differential form of the moving-boundary equation. The result for acid-base systems is a single algebraic equation valid universally for a zone comprising any number of constituents (mono- or polyhydric strong or weak acids or bases and/or amphoteric compounds). The value of the described solution against previous models consists in its explicit form, expressing the system eigenmobility of a homogeneous zone of given composition as a function of only known quantities. The obtained equation is shown to be the common source of various simplified equations obtained in the past for particular simple systems. The applicability of the simplified equations is discussed in terms of completeness of the results (number of output system eigenmobilities). For non-buffered systems, the occurrence of a previously unreported non-zero value of system eigenmobility is discussed that is equal to the arithmetic average of mobilities of the solvent ions.