Relative permeability of CBM reservoirs: Controls on curve shape

Relative permeability to gas and water for 2-phase flow coalbed methane (CBM) reservoirs has long been known to exhibit a strong control on (gas and water) production profile characteristics. Despite its important control on both primary and enhanced recovery of CBM for coal seams that have not been fully dewatered, relative permeability in coal has received little attention in the literature in the past decade. There are few published laboratory-derived curves; these studies and their resulting data represent a small subset of the commercial CBM reservoirs and do not allow for a systematic investigation of the physical controls on relative permeability curve shape. Other methods for estimation of relative permeability curves include derivation from simulation history-matching, and production data analysis. Both of these methods will yield pseudo-relative permeability curves whose shapes could be affected by several dynamic CBM reservoir and operating characteristics.The purpose of the current work is to perform a systematic investigation of the controls on CBM relative permeability curve shape, including non-static fracture permeability and porosity, multi-layer effects and transient flow. To derive the relative permeability curves, effective permeability to gas and water are obtained from flow equations, flow rates and pressure data. Simulated cases are analyzed so that derived and input curves may be compared allowing for investigation of CBM reservoir properties on curve shape. One set of relative permeability curves that were input into the simulator were obtained from pore-scale modeling. Field cases from two basins are also examined and controls on derived relative permeability curve shape inferred. The results of this work should be useful for future CBM development and greenhouse gas sequestration studies, and it is hoped that it will spark additional research of this critical CBM flow property.     

黄河中游区水,沙变化趋势及其预测

本文用灰色系统分析方法对黄河中游区干、支流主要测站水、沙资料进行研究、评估,阐明了水、沙多年变化趋势,论证了水、沙多年变化的原因,并对几个测站试作水、沙长期预测。     

Hilbert曲线层级演进关系

网格编码代数是当前全球空间网格研究中的难点,也是推动全球空间网格从数据组织管理框架发展成为新一代空间分析模型的理论基础。Hilbert曲线是设计全球空间网格单元编码的重要工具。本文以Hilbert曲线序列码作为八叉树立体网格单元的唯一编码,由Hilbert曲线数学性质推导得到网格单元Hilbert码的层级演进关系表,进而设计了用于网格编码代数运算的若干操作算子,为构建全球空间网格分析理论与方法提供参考。     

一种地下瞬变电磁法场值曲线的解释方法

均匀大地表面上大回线源在地下形成的瞬变电磁场解析计算式很复杂,无法用常规方法定义其视电阻率,而场值曲线本身分辨率低,进行分层解释困难。对大回线源在地下形成的瞬变电磁场场值,用由第一层介质充满半无限大地时的场值进行归一化的方法进行解释,经理论计算表明,与地面装置条件下的电阻率曲线进行解释有异曲同工之妙     

几种幼鱼曲线游泳能力的比较研究

于１９８９年３－５月，利用视觉运动反应方法测定了黑鲷、黄鳍鲷、鲻鱼、鲤鱼和白鲢５种幼鱼的曲线游泳能力。结果表明，幼鱼游泳速度随环形水道半径增加而加快，但加快的速率逐渐减缓。随游泳时间的延长，游泳速度线性下降，实测耐久时间，黑鲷为６６．７ｍｉｎ；黄鳍鲷为６６．８ｍｉｎ；鲻鱼为１０４．４ｍｉｎ；鲤鱼为７０．３ｍｉｎ；白鲢为５８．８ｍｉｎ。游泳能力指数，黑鲷为２９０．６；黄鳍鲷为１４７．３；鲻鱼为４８５     

Constrained Smoothing of Noisy Data Using Splines in?Tension

A method of fitting a smooth cubic spline curve through noisy data points is presented. Overshoots of the spline curve between data points were prevented by applying tension to the fit using a quadratic spring approximation, which allowed a linear inverse theory approach to be adopted. Error-bars in the measured data were mapped through the inversion process to give the covariance of the fitted curve. This is an improvement over previous methods, which largely neglect the effect of data errors on the fit. Another improvement is to impose fixed constraints on the fit by simultaneously applying the method of Lagrange multipliers. The effect of these constraints on the covariance of the fitted curve is quantified using results from linear algebra. Example applications to synthetic data and a record of magnetic inclination from Hawaii are given.     

城市化对"城市浑浊岛效应"影响分析

采用乌鲁木齐市和其郊区日照时间的差值作为衡量城市"浑浊岛效应"的标准,以乌鲁木齐市城市化九项指标的综合值作为衡量城市化的标准,数据的跨度从1976—2004年;对这两列数值进行相关分析。文章的结论包括:城市化与"城市浑浊岛"效应有很强的相关性;城市化对城市浑浊岛的影响分3个阶段;乌鲁木齐市的浑浊岛效应符合环境库兹涅茨规律。     

基于RS和GIS的中尺度流域土地利用空间结构变化——以伊洛河流域中部洛宁县为例

选择伊洛河流域中部洛宁县为研究区域 ,运用RS和GIS技术 ,分别提取研究区 1 987和 1 999年以地貌类型为单元的土地利用数据绘制罗伦兹曲线。结果表明 :1 987～ 1 999年 ,各地类在各类地貌单元的集中与分散程度的整体状况未发生变化 ,其分布的集中程度依次为建设用地 >水域 >林地 >耕地 >未利用土地 ;但集中和分散程度发生明显变化 ,其中林地分布趋于集中 ,耕地、水域和未利用土地趋于分散 ,而建设用地基本没有变化 ,其原因主要是该时段川涧区林地大幅度增加 ,而其它地貌单元林地面积大量减少所致     

人口预测方法及可靠性探讨

运用曲线拟合和灰色系统理论对我国人口发展进行预测，并对预测结果进行可靠性检验。     

RUNOFF-ENERGY FACTORS FORMUSLE SEDIMENT-YIELD MODEL FOR SURFACE MINES

1INTRODUCTIONSediment-yieldestimatesarerequiredforsurfacec0al-minepermitsunderFederalandStatelaws-Estimatesareneededfordeterminingtheimpactsofminingandreclamationduringmine0Peration,fordiversi0nandsmallimpoundmentdesigns,andforsizingsedimentpondstocontrolsedimenttransporteddownstfeam0faproposedminesite.Technologiesavailablef0rsediment-yieldestimationsincludetheUniversalSoilLossEquati0n(USLE,WischmierandSmith,l978);theWaterErosionPredictionPr0ject(WEPP,FlanaganandLivingst0n,l995),…