应用模糊综合评判方法优选水力压裂井

考虑到水力压裂井压裂效果影响因素之间的关系复杂,且各影响因素本身具有模糊性,这些因素很难用常规方法量化研究,尝试应用模糊综合评判的方法进行水力压裂井优选.通过对影响压裂效果的各个因素进行分析,优选出生产压差、含水率、压前增油量、孔隙度、渗透率、小层有效厚度、加砂量等7个主要因素,并应用层次分析法得到各个影响因素的权重,最后采用模糊综合评判方法对水力压裂井进行评估,最终判定其是否适合压裂并对压裂井进行优选,现场实际应用表明,该方法可以提高现场的工作效率和选井的客观性、准确性.     

基于层次分析的精控压裂井层模糊评价研究

精控压裂是高含水、特高含水油田薄差油层改造的重要措施,合理准确的选井选层标准是精控压裂取得较好措施效果的前提.基于层次分析方法结合模糊数学理论,形成了一种新的精控压裂井层优选评价方法,利用层次分析方法明确主要影响因素,结合模糊综合评价定量评价措施效果并形成精控压裂选井选层标准.应用结果验证了方法的准确性及适用性,对精控压裂井层优选具有一定的指导意义和应用价值.     

灰色理论结合专家系统预测煤层气井压裂效果

煤层气井水力压裂效果受煤层条件、煤层气井条件、压裂施工参数等影响,压裂效果难以预测.通过对煤层气井压裂后累积增产量分析,从中确定出煤层厚度、煤层深度、煤层渗透率等26个影响煤层气井压裂效果的因素.运用灰色关联法筛选主要因素和次主要因素,并分别建立不同的隶属函数用于专家系统的知识库建立,形成一种灰色理论结合专家系统的煤层气井压裂效果预测方法.将方法运用与鄂尔多斯某区块,对200组测试数据进行计算,预测错误率仅为3.5%.计算结果表明,方法预测结果准确可靠,可为煤层气井压裂优化提供指导.     

基于灰色关联法的水平井压裂参数优化研究

针对低渗透薄互砂岩油藏A油田C9区块水平井井区储层物性差、非均质性强、开发难度大等问题,为改善水平井井区开发效果、提高水平井单井产能,应用灰色关联法,结合数值模拟软件,分析影响压裂水平井产能的主要因素,开展水平井压裂参数优化研究,结果表明裂缝半长和裂缝间距是影响压裂水平井产能的主要因素,优选出水平井压裂方案:裂缝半长为...     

应用模糊综合评判和灰色关联度分析评价水平井多级压裂效果

水平井多级压裂是低渗透和非常规油气田开发的有效技术手段,其压后产能评价问题已成为相关研究的热点和难点.水平井多级压裂压后产能的各项影响因素之间关系复杂,通过常规理论分析量化研究困难,压裂效果很难准确预测.本文提出应用模糊综合评判和灰色关联度分析相结合的方法,对多级压裂水平井的压裂效果进行评价.首先运用灰色理论分析影响压裂效果的各因素之间的灰色关联度,计算各影响因素在综合评判中的权重值,再结合模糊综合评判方法,对多级压裂井压后效果进行预测评价.通过目的区块24口多级压裂水平井压后效果评价与实际生产情况对比,表明模型计算准确率达到95.8%,评价结果准确可靠.     

压裂效果预测方法研究

预测油井压裂效果对实施增产措施决策意义重大.应用科学的数学统计方法建立了大庆油田采油二厂某区块压裂措施库,采用灰色关联方法分析影响压裂效果的主要因素,应用多元回归方法、逐步回归方法、人工组合回归方法分别建立预测模型,进而建立起适用于不同压前含水和液量级别的预测图版,增油量绝对误差在1.5t以内的井的符合率达到77.4%.方法可操作性强,预测符合率较高,可用于指导优化压裂工艺,提高剩余储量动用程度.     

灰色关联度进行低产低效井影响因素分析及措施效果增油量预测模型建立

为了确定低产低效影响因素及挖潜措施潜力,利用灰色关联度进行低产低效井影响因素分析,优选出影响产能的主要因素,结合多元线性回归方法与数理统计理论,建立了X油田油井压裂措施增油量预测模型和堵水井降水量预测模型.有机结合油井降水措施和增油措施的经济界限模型,可以准确预测低产低效井压裂增油潜力及堵水降水增油潜力,误差5%-10%以内,有效指导低效低产井再开发.     

灰色关联方法的分析与应用

选取某油田某区块为试验区,应用灰色关联方法分析影响压裂效果的主要因素,分别采用均值变换和极差变换方法对样本库的16口井的日增油量进行预测,并通过多元回归方法建立预测模型,预测结果显示极差变换方法预测结果较为准确,预测井的绝对误差平均值为0.52 t/d,能够满足现场压裂工艺的实施要求.     

致密气储层压裂水平井产能影响因素排序

致密气是我国重要的战略接替资源,其开发理论研究处于起步阶段.水平井压裂是非常规致密气藏实现工业开采价值均有效技术手段,而压裂后产能影响因素的研究是该类气藏能否实现工业价值的关键.提出灰色关联原理和正交试验设计方法综合应用的方法对产能影响因素进行排序.首先利用灰色关联原理初步确定影响因素排序;再利用正交试验设计研究影响因素,并弥补灰色关联理论对因素之间相互制约和促进关系分析的不足;最后综合确定致密气藏单井产能影响因素的排序.研究表明:储层渗透率是影响单井无阻流量的决定性因素;其他主要因素依次为水平井段长度、有效厚度、裂缝条数;裂缝半长、水平井段纵向位置以及生产压差为次要因素.上述两种数学方法分析结果具有良好的一致性和实用性,对致密气藏现场实际生产具有重要的指导意义.     

物业管理招标中的层次关联比选

应用层次分析法确定影响物业管理投标书总体方案的各因素间权重 ,根据灰色关联理论建立了对投标书进行总体综合评价并排序优选的数学模型 ,给出了计算实例 .     

A REPRESENTATION FORMULA RELATED TO SCHR(O)DINGER OPERATORS

Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.     

On a class of self-similar processes with stationary increments in higher order Wiener chaoses

We study a class of self-similar processes with stationary increments belonging to higher order Wiener chaoses which are similar to Hermite processes. We obtain an almost sure wavelet-like expansion of these processes. This allows us to compute the pointwise and local Hölder regularity of sample paths and to analyse their behaviour at infinity. We also provide some results on the Hausdorff dimension of the range and graphs of multidimensional anisotropic self-similar processes with stationary increments defined by multiple Wiener–Itô integrals.     

Qualitative Analysis of Bifurcating Solutions in the Lengyel-Epstein Model

One of the most fundamental problems in theoretical biology is to explain the mechanisms by which patterns and forms are created in the＇living world. In his seminal paper ＂The Chemical Basis of Morphogenesis＂, Turing showed that a system of coupled reaction-diffusion equations can be used to describe patterns and forms in biological systems. However, the first experimental evidence to the Turing patterns was observed by De Kepper and her associates（1990） on the CIMA reaction in an open unstirred reactor, almost 40 years after Turing＇s prediction. Lengyel and Epstein characterized this famous experiment using a system of reaction-diffusion equations. The Lengyel-Epstein model is in the form as follows     

(0,1 ;0)-INTERPOLATION ON INFINITE INTERVAL (-∞, +∞)

In this paper, we study the explicit representation and convergence of (0, 1; 0)-interpolation on infinite interval, which means to determine a polynomial of degree ≤ 3n - 2 when the function values are prescribed at two set of points namely the zeros of Hn(x) and H′n(x) and the first derivatives at the zeros of H′n(x).     

On a class of Riemann surfaces

It is considered the class of Riemann surfaces with dimT1 = 0, where T1 is a subclass of exact harmonic forms which is one of the factors in the orthogonal decomposition of the spaceΩH of harmonic forms of the surface, namely The surfaces in the class OHD and the class of planar surfaces satisfy dimT1 = 0. A.Pfluger posed the question whether there might exist other surfaces outside those two classes. Here it is shown that in the case of finite genus g, we should look for a surface S with dimT1 = 0 among the surfaces of the form Sg\K , where Sg is a closed surface of genus g and K a compact set of positive harmonic measure with perfect components and very irregular boundary.     

CONTENTS OF VOLUME 30

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Instructions for contributions

正Applied Mathematics-A Journal of Chinese Universities,Series B(Appl.Math.J.Chinese Univ.,Ser.B)is a comprehensive applied mathematics journal jointly sponsored by Zhejiang University,China Society for Industrial and Applied Mathematics,and Springer-Verlag.It is a quarterly journal with     

Journal of Mathematical Research with Applications Guide for Authors

正Journal overview:Journal of Mathematical Research with Applications(JMRA),formerly Journal of Mathematical Research and Exposition(JMRE)created in 1981,one of the transactions of China Society for Industrial and Applied Mathematics,is a home for original research papers of the highest quality in all areas of mathematics with applications.The target audience comprises:pure and applied mathematicians,graduate students in broad fields of sciences and technology,scientists and engineers interested in mathematics.     

Staircase transportation problems with superadditive rewards and cumulative capacities

A cumulative-capacitated transportation problem is studied. The supply nodes and demand nodes are each chains. Shipments from a supply node to a demand node are possible only if the pair lies in a sublattice, or equivalently, in a staircase disjoint union of rectangles, of the product of the two chains. There are (lattice) superadditive upper bounds on the cumulative flows in all leading subrectangles of each rectangle. It is shown that there is a greatest cumulative flow formed by the natural generalization of the South-West Corner Rule that respects cumulative-flow capacities; it has maximum reward when the rewards are (lattice) superadditive; it is integer if the supplies, demands and capacities are integer; and it can be calculated myopically in linear time. The result is specialized to earlier work of Hoeffding (1940), Fréchet (1951), Lorentz (1953), Hoffman (1963) and Barnes and Hoffman (1985). Applications are given to extreme constrained bivariate distributions, optimal distribution with limited one-way product substitution and, generalizing results of Derman and Klein (1958), optimal sales with age-dependent rewards and capacities.To our friend, Philip Wolfe, with admiration and affection, on the occasion of his 65th birthday.Research was supported respectively by the IBM T.J. Watson and IBM Almaden Research Centers and is a minor revision of the IBM Research Report [6].