有回归分析方法优选有杆泵抽油井的抽汲参数

本文根据现场测试数据，建立了抽油机井地面效率、井下功率损失与排量系数的回归公式，以此为基础建立了以系统效率为目标函数的抽油机井抽汲参数优化设计模型，从而提出了一种优选抽油机井抽汲参数的新方法。     

用回归分析方法优选有杆泵抽油井的抽汲参数

姚春冬，张树江．用回归分析方法优选有杆泵抽油井的抽汲参数，数理统计与管理，１９９７，１６（１），９～１５．本文根据现场测试数据，建立了抽油机井地面效率、井下功率损失与排量系数的回归公式，以此为基础建立了以系统效率为目标函数的抽油机井抽汲参数优化设计模型，从而提出了一种优选抽油机井抽汲参数的新方法     

基于间隙元法对抽油杆扶正器合理间距进行计算

采用间隙元来模拟抽油杆与油管内壁的接触摩擦状态,将梁单元与间隙元结合,建立了抽油杆力学分析的有限单元法.方法能够求解出抽油杆柱在不同工况(上、下冲程)的受力变形状态,抽油杆与油管的接触摩擦状态.同时,建立了抽油杆扶正器合理间距计算原则,使中间抽油杆与油管不发生接触、接箍和扶正器与油管的接触摩擦力最小化,使抽油杆与油管偏磨降到最低.对抽油机井杆管偏磨以及治理具有一定的理论指导意义.     

有杆抽油系统的数学建模及诊断

以有杆抽油系统作为研究对象,定量描述了四连杆结构抽油系统中光杆悬点的运动规律,给出了悬点在一个冲程中的位移函数、速度函数、加速度函数的表达式.分析利用Gibbs模型将题中给出的悬点示功图转化为泵功图,并利用泵功图对附件1、2中的油井产液量进行估算,最后理论推导了阻尼系数计算方法.     

最优化与正交法交流会“优化成果奖”

组织推广特别奖 肖培基、江振东,合肥市科委,“合肥市全面推广正交优化法”一等奖 吴宝元等,沈阳黄金学院贵金属材料厂,“正交法在银稀土电触头研制中的应用” 赵宝芳等,安徽阜阳纺织厂,“应用正交法优化纺纱工艺降低棉纱条干不匀率” 丁秀华,江苏淮安市经委,“正交优化法的推广与实践” 董世民等,大庆石油学院,“抽油机井抽汲参数优化设计的研究”二等奖 陈建信,杭州化工研究所,“非线性整数规划的求解” 肖兵等,湖南省科协,“农业多因素试验设计与统计分析” 徐建兰等,无锡市现场统计研究会,“FK-1铝箔腐蚀微机优化控制系统”──铝 泊腐…     

有杆抽油系统工况诊断的数学模型研究

小波矩特征法是一种既能反映图像的全局信息,又能反映局域信息,并且具有旋转、平移和缩放不变形的图像特征提取方法,在模式识别中能大大提高对近似目标识别的能力.为保证油井正常生产,精确快速地诊断出有杆抽油系统的工况,基于小波矩特征和自组织竞争神经网络(SCNN)建立了一种泵功图诊断模型.利用Matlab将悬点示功图转化为泵功图,然后基于小波矩特征法提取泵功图的小波矩特征并优选出合适的小波矩特征量,使用SCNN识别诊断.仿真研究表明,模型能够可靠的诊断有杆抽油系统的工况,实现简单,准确率高,适用于现场诊断,具有一定的工程应用前景.     

“有杆抽油系统的数学建模及诊断”综述

2012年第9届全国研究生数学建模竞赛C题"有杆抽油系统的数学建模及诊断"来自实际问题,希望通过地面数据采用数学方法推算地下泵的相关数据,从而实时判断油井运行情况、估算产量.对问题的提出背景、解决问题的基本思路、参赛及评阅情况、存在问题及研究建议等方面进行了综述.     

基于示功图理论的有杆泵采油产液量计算

针对油田有杆抽油系统,利用Gibbs一维带阻尼的波动方程数学模型将悬点示功图转化为泵功图,并提出了两个估算油井产液量的数学模型.经实际数据验证表明,泵功图相对于悬点示功图向下平移了一段距离,消除了抽油杆柱对抽油泵工况分析的影响;两种产液量估算模型能较好的估算油井产液量;具有一定的适用性和可靠性.     

自适应时间比例同步算法

本针对现有的时间比例同步算法具有时间比例固定、系统运行效率低、易导致系统中消息因果关系不正确的特点，运用模糊控制方法来动态调整系统运行的时间比例，设计了一种自适应时间比例同步算法，尽量减少仿真中不合理的现象，提高系统的运行效率。     

外源投入型两阶段制造系统网络DEA效率分析研究

制造过程评价是改善制造系统效率的重要一环,传统的评价方法将每个制造系统决策单元视为黑箱来研究整体效率,忽略了中间产品转化信息及投入要素在各子过程中的配置信息。针对两阶段(第二阶段有外源性新投入)制造系统的效率评估问题,分别在固定规模报酬和可变规模报酬假设下,充分利用制造系统中间产品的转化及外源投入要素的配置信息,建立了制造系统网络DEA效率测度及分解模型,建模方法遵循客观评价原则,无需事先主观确定子效率和系统效率之间的组合关系。并将其应用于钢铁制造系统效率测度与分解,研究结果表明该方法能够挖掘决策单元内部子单元的效率情况,帮助决策者发现复杂制造过程非有效的根源,为复杂制造过程的整体效率测度及分解提供了有效的分析方法。     

应用模糊综合评判方法优选卫星油田潜力低产低效井

油田进入特高含水开发期后,低产低效井数成逐年上升的趋势,如何识别低产低效井已经成为油田特高含水期高效开发的一个重要问题.借助模糊数学和系统工程层次分析原理,考虑到影响油井产能因素的复杂性和不均衡性,将各因素按其在不同层次上对事物的影响程度分类,然后确定各因素最终的权重,形成了一套优选低产低效井的模糊综合评判方法.现场实际应用表明,方法可以提高现场的工作效率和选井的客观性、准确性.     

The number of energy levels of a particle in a uniform MQW structure

A recently obtained multilayer equation that gives the eigenvalues of the energy of a quantum particle in an arbitrary one-dimensional piecewise constant potential field is studied. In particular, this equation can be used to calculate the eigenvalues of the particle’s energy in an MQW structure, in which the potential takes only two different values in the various layers. A formula is analyzed that was obtained earlier by the author for the number of energy levels in a uniform MQW structure, i.e., in a structure with potential wells and walls of constant widths. The equation is substantiated for all uniform MQW structures. It is proved that the number of energy levels in a uniform MQW structure increases indefinitely with unlimited growth of the number of potential wells. The existence of uniform MQW structures with an arbitrarily large prescribed number of potential wells and with a single energy level is proved.     

基于GMDH-SVR致密气开发过程参数优化

本文基于非常规油气的致密气开发流程图,利用K-means将4291口气井根据单位压降产气量聚为三类。通过改进GMDH算法对训练集和测试集样本规模比例的完备性和样本次序的随机性进行研究以增强算法鲁棒性。以单位压降产气量作为评价参数对三类气井开发效能主要相关的11个参数进行特征提取并统计各参数作为主成分的概率,选择累计概率80%及以上最少参数作为SVR模型的输入变量,单位压降产气量作为输出变量,选择RBF 作为核函数。分别使三类井各一个样本井的压裂参数上下浮动20%,应用SVR模型统计相应单位压降产气量变化范围是[-18.08%,13.42%]、[-2.34%,5.39%]、[-16.10%,15.21%],分析不同压裂参数组合对单位压降产气量的影响趋势,确定工程实践最优压裂参数,提高气井效能。     

Workforce cross-training decisions in field service systems with two job types

When job types are heterogeneous in a multi-server service system, pooling servers to reduce system delay requires cross-training. Managers should balance a reduction in customer waiting time with high service costs and possibly reduced server efficiency due to cross-training. In a field service system with two job types and a fixed number of servers, the determination of the mix of dedicated and cross-trained servers is a critical managerial decision. We were motivated by a real field service situation to study a model where the objective is to minimize the sum of the average service costs and the customer delay costs per unit time. We use simulation to investigate the impact of various system parameters such as the number of servers, server utilization, and server efficiency on the optimal workforce mix.     

应用模糊综合评判方法识别水驱优势渗流通道井和层

在油田注水开发过程中,由于储层平面非均质性、流体非均质性及开发条件的影响,在平面上会出现注入水突进的情况.注水井中的注入水向不同方向驱油,推进往往是不均匀的,一般总有一个方向突进最快,且经过长期水洗之后,这个方向有可能发展成大孔道,形成水驱优势渗流通道.建立应用模糊综合评判方法识别水驱优势渗流通道井和层的数学模型,应用水驱优势渗流通道分析判定软件,对河南双河油田ⅦⅣ油组主力油层(Ⅷ1、Ⅳ1、4、5)274口井进行了实例计算,识别出水驱优势渗流通道油水井共97口,其中水井43口,油井54口,识别出14个水驱优势渗流层位.通过油藏工程和数值模拟方法进行了验证,表明运用综合评判方法识别水驱优势渗流通道井和层是一种客观有效的方法,评价方法计算方便,易于操作和推广.     

Use of goal programming and integer programming for water quality management—A case study of Gaza Strip

This paper describes a project dealing with achieving an optimum mix of water from different underground wells, each having different amounts of nitrates and chlorides. The amounts of chlorides and nitrates in each of the wells may be higher or lower than the World Health Organization (WHO) standards. Therefore, the optimum mix would be the one that meets WHO standard which is 250 mg/l for chlorides and 50 mg/l for nitrates. A goal programming model was developed to identify the combination of wells along with the amounts of water from each well that upon mixing would result in minimizing the deviation of the amounts of chlorides and nitrates from the standards set by WHO. The output of the goal programming model along with the coordinates of the wells identified above was then used for a second model that determines the locations of the mixing points “reservoirs” in such a way that minimizes the total weighted distances from the corresponding wells. Finally, an easy-to-use pumping schedule was developed using integer programming. Results indicate that for the case study, there exist several optima which make it easier for the decision maker to consider other intangible factors if there are any.     

An exponential transformation based splitting method for fast computations of highly oscillatory solutions

Splitting, or decomposition, methods have been widely used for achieving higher computational efficiency in solving wave equations. A major concern has remained, however, if the wave number involved is exceptionally large. In the case, merits of a conventional splitting method may diminish due to the fact that tiny discretization steps need to be employed to compensate high oscillations. This paper studies an alternative way for solving highly oscillatory paraxial wave problems via a modified splitting strategy. In the process, an exponential transformation is first introduced to convert the underlying differential equation to coupled nonlinear equations. Then the resulted oscillation-free system is treated by a Local-One-Dimensional (LOD) scheme for desired accuracy, efficiency and computability. The splitting method acquired is asymptotically stable and easy to use. Computational experiments are given to illustrate our numerical procedures.     

The reliability of a test procedure for identifying defective components

Fast and simple tests for detecting defects in components (or units) may be less reliable but they have obvious advantages over those that are exact but more costly and/or time-consuming. In this study, a model is proposed for predicting the reliability of a test procedure where simple and exact tests are combined so as to minimize the number of costly and time-consuming tests. The maximum likelihood method is used to estimate the necessary parameters, such as the actual number of abnormal units in a multi-unit system under test, and the probabilities of correctly and incorrectly identifying a unit as abnormal.     

Efficient heuristics for the workover rig routing problem with a heterogeneous fleet and a finite horizon

Onshore oil fields may contain hundreds of wells that use sophisticated and complex equipments. These equipments need regular maintenance to keep the wells at maximum productivity. When the productivity of a well decreases, a specially-equipped vehicle called a workover rig must visit this well to restore its full productivity. Given a heterogeneous fleet of workover rigs and a set of wells requiring maintenance, the workover rig routing problem (WRRP) consists of finding rig routes that minimize the total production loss of the wells over a finite horizon. The wells have different loss rates, need different services, and may not be serviced within the horizon. On the other hand, the number of available workover rigs is limited, they have different initial positions, and they do not have the same equipments. This paper presents and compares four heuristics for the WRRP: an existing variable neighborhood search heuristic, a branch-price-and-cut heuristic, an adaptive large neighborhood search heuristic, and a hybrid genetic algorithm. These heuristics are tested on practical-sized instances involving up to 300 wells, 10 rigs on a 350-period horizon. Our computational results indicate that the hybrid genetic algorithm outperforms the other heuristics on average and in most cases.