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低渗透油藏生产井关井测压时间的计算与应用 总被引:4,自引:4,他引:0
低渗透油藏的生产井压裂后,在单井试油试采过程中,压力恢复测试关井时间不同,其中有些井压力恢复曲线不能出现边界反应段,渗流不能反映地层中真实流动特征。针对这种情况,基于长庆绥靖油田塞39井区长:低渗透油藏大量试井和实际生产资料,利用现代试井解释理论,研究合理关井时间的界限及其计算方法。结果表明,当油井关井测压时间达到3倍地层径向流开始出现的时间后,利用此时的压力数据解释地层参数和地层压力,其结果的误差小于5%,同时能较准确地判断边界类型。计算的理论曲线和霍纳法解释值非常接近,对于塞39井区,若预先知道某生产井地层有效渗透率值,可从理论曲线查出压力恢复试井的关井时间,否则,建议按照该井区地层有效渗透率(大约在6mD左右),将不稳定试井测试时间控制在25d以上为宜。图4表3参14 相似文献
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Ming-yan Liu Wen Leng Ai-hong Qiang 《Chemical Engineering and Processing: Process Intensification》2008,47(12):2066-2075
In this work, the instantaneous data of inner wall temperatures obtained at given axial positions but for different heated tubes or at various axial positions but at the same heated tube in a tube-bank fluidized bed evaporator with a vapor–liquid–solid external natural circulation flow were analyzed by employing linear and nonlinear time series analysis methods, including correlation dimension and Kolmogorov entropy analyses besides time domain, power spectrum and autocorrelation analyses. It is found that nonlinear characteristics of the wall temperature time series vary with spatial position in the evaporator at given operation conditions, and thus the multi-phase flow boiling behavior. However, the signals obtained at given axial position but different heated tubes in the evaporator exhibit more similar nonlinear evolution behavior, and those measured in the same heated tube but at different axial heights in the evaporator undergo more distinct nonlinear dynamic behavior. Multi-scale phenomena in different spatial positions are also found and discussed. These transient aspects of inner wall temperatures are closely related to the average holdup of solid particles and motion of vapor bubbles in vapor–liquid–solid flow. These results can provide some valuable information on the system modeling and controlling from the point of view of nonlinearity. 相似文献
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The effects of boiling Aqua Regia (AQ), N2/Cl2 plasma followed by AQ and O2 plasma followed by AQ surface treatments prior to Ni/Au (20 nm/20 nm) metallization to p-GaN:Mg (∼ 3 × 1017 cm− 3) have been investigated. N2/Cl2 plasma was employed in a bid to lower the Ga/N and O/Ga ratios of the GaN surface to improve the contact properties to p-GaN, while O2 plasma was employed as an alternative to incorporate O into the Ni/Au system. Results show that a low Ga/N ratio does not necessarily correspond to a better contact. The positive effect of O2 over N2 anneal is observed only for the AQ-treated sample, although the mechanisms responsible for its positive effect: NiO formation and Ni/Au layer-reversal were observed for all O2-annealed contacts. We conclude that the effect of O2 anneal on the Ni/Au contact is dependant on the p-GaN surface prior to metallization. 相似文献
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冷英男 《辽宁石油化工大学学报》1994,(3)
提出了一个简单的理论模型.旨在为数据处理系统的性能评价提出一个理论框架.以此框架为基础,可形成实用的简单评估方法.该模型只含两个参数,它们是统计量,可用统计方法确定. 相似文献
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水轮机调速器与电网负荷频率控制 总被引:4,自引:3,他引:1
在现代电力系统中,水轮机调速器已成为水轮机控制系统的控制核心。文中叙述了水轮机调速器与电网负荷频率控制之间的关系,分析了调速器在电网一次调频、二次调频中的作用、静态特性和动态特性;通过建模、仿真及现场试验,提出了机组并联于大电网工况下的调速器PID参数整定范围和应有的机组功率控制模式。 相似文献
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Tree-based partitioning of date for association rule mining 总被引:1,自引:1,他引:0
The most computationally demanding aspect of Association Rule Mining is the identification and counting of support of the frequent sets of items that occur together sufficiently often to be the basis of potentially interesting rules. The task increases in difficulty with the scale of the data and also with its density. The greatest challenge is posed by data that is too large to be contained in primary memory, especially when high data density and/or low support thresholds give rise to very large numbers of candidates that must be counted. In this paper, we consider strategies for partitioning the data to deal effectively with such cases. We describe a partitioning approach which organises the data into tree structures that can be processed independently. We present experimental results that show the method scales well for increasing dimensions of data and performs significantly better than alternatives, especially when dealing with dense data and low support thresholds.
Shakil Ahmed received a first class BSc (Hons) degree from Dhaka University, Bangladesh, in 1990; and an MSc (first class), also Dhaka University, in 1992. He received his PhD from The University of Liverpool, UK, in 2005. From 2000 onwards he is a member of the Data Mining Group at the Department of Computer Science of the University of Liverpool, UK. His research interests include data mining, Association Rule Mining and pattern recognition.
Frans Coenen has been working in the field of Data Mining for many years and has written widely on the subject. He received his PhD from Liverpool Polytechnic in 1989, after which he took up a post as a RA within the Department of Computer Science at the University of Liverpool. In 1997, he took up a lecturing post within the same department. His current Data Mining research interests include Association rule Mining, Classification algorithms and text mining. He is on the programme committee for ICDM'05 and was the chair for the UK KDD symposium (UKKDD'05).
Paul Leng is professor of e-Learning at the University of Liverpool and director of the e-Learning Unit, which is responsible for overseeing the University's online degree programmes, leading to degrees of MSc in IT and MBA. Along with e-Learning, his main research interests are in Data Mining, especially in methods of discovering Association Rules. In collaboration with Frans Coenen, he has developed efficient new algorithms for finding frequent sets and is exploring applications in text mining and classification. 相似文献