用随机介质模型方法描述孔洞型油气储层

孔洞型储集层具有强烈的非均质性,在空间分布上变化剧烈,规律性差,其地球物理参数(如速度、密度、弹性参数等)在空间上的变化很难用传统的层状介质模型进行刻画.本文借助随机模型方法,研究孔洞型储层中不同孔洞尺度、分布密度与模型参数的关系,建立反映实际孔洞油气储层介质地球物理参数空间分布统计特征的随机介质模型,以更方便地对孔洞型油气储层进行描述,并为碳酸盐岩孔洞型储层地震反射特征的研究提供有效的方法途径.     

非均匀地表蒸散遥感研究综述

本文评述了目前常用的遥感估算地表蒸散方法,包括地表能量平衡模型、Penman-Monteith类模型、温度—植被指数特征空间方法、Priestley-Taylor类模型和其他方法。然而使用这些方法估算地表蒸散时会面临严重的尺度效应,而产生尺度效应的根本原因之一是地表异质性,在分析了非均匀下垫面对水热通量遥感反演造成的影响后,介绍了面积加权、校正因子补偿与温度降尺度3种尺度误差纠正方法;并从地面观测实验的角度简述了非均匀下垫面水热通量真实性检验的研究;最后探讨了将来建立更具时空代表性的非均匀下垫面地表蒸散遥感估算模型可能会面临的一些挑战。     

胜坨油田坨28断块沙河街组二段储层非均质性定量研究

运用模糊数学方法计算非均质综合指数和计算渗透率非均质参数,对胜坨油田坨28断块沙河街组二段储层的非均质性进行了定量研究。结果表明：储层的层间,层内和平面非均质性强,随着开发注水的深入进行,非均质性有减弱趋势,但减弱幅度不大;各小层及其韵律层在不同开发时期的非均质程度有明显的差异。沉积微相控制储层非均质程度;成岩作用使非均质性复杂化;注采井网不完善,加剧了非均质性的差异性。研究成果在剩余油挖潜的应用中起到重要作用。     

VTI介质多波速度与各向异性系数求取及应用

针对具有垂直对称轴的横向各向同性(VTI)介质,研究了多波速度与地层各向异性系数之间的关系。采用适应大偏移距以及强各向异性介质的双平方根方程,进行速度和各向异性系数分析,并将批量计算与交互解释相结合,实现了高精度各向异性介质多波速度与各向异性系数提取,并形成了一套利用多波地震资料求取地震波纵、横波速度及各向异性系数的方法和软件。所求取的参数可用于多波地震资料处理,提高多波资料的成像质量,也可为地层地质解释提供参考。实际资料的应用效果证明了该方法和软件的正确性及有效性。     

Simulation of groundwater level recovery in abandoned mines,Fengfeng coalfield,China

Abandoned mines are of high potential risk as they could be a large underground storage of pollutants(heavy metals and organic wastes, etc.). Various physical, chemical and biological reactions would take place when groundwater flows into underground spaces, which makes abandoned mine a huge potential hazard to groundwater environment. The recovery of groundwater level is one of the key elements controlling the reactions and causing such hazards. This paper simulated groundwater level recovery processes in the abandoned mines, Fengfeng coalfield by using the computer program FEFLOW. The paper integrated the pipe flow model, "three zones" model and groundwater inrush(discharge) model in the simulation of groundwater in the complex laneway-aquifer system. Groundwater flow in the laneway systems was considered pipe flow and described in Bernoulli equation. The water-bearing medium(coal seam roof) overlying the laneway systems was divided into "three zones" composed of the caving zone, fissure zone and bending zone based on the disruption degrees of previous mining. Groundwater in the Ordovician limestone aquifer(bottom of coal seam) flowing into laneway systems was considered a major inrush/recharge source, and its flow rate was calculated by an inrush(discharge) model which was newly developed in this study and incorporated into FEFLOW. The results showed that it would take approximately 95 days for groundwater in abandoned mines to recover to regional groundwater level elevation, and the total amount of water filling up would be about 1.41195×10~7 m~3, which is consistent with the actual data. The study could be of theoretical and practical significance to mitigate abandoned mines' hazards and improve mine groundwater utilization.     

非均匀下垫面陆面过程参数化问题研究进展

非均匀下垫面对陆面过程模式应用有着重要影响。若将下垫面一概视为均一,在很多情况下会影响模式模拟的准确性。本文详细介绍了目前非均匀地表陆面过程参数化的方法(Mosaic法、统计—动力法和其它方法),初步分析了这些参数化方法的缺陷,并简单探讨了陆面参数尺度转换问题,最后对今后研究的问题给出了建议,其中特别提出要寻找适当方法实现陆面物理量不同尺度间的转换。     

基于BISQ模型双相各向同性介质中地震波数值模拟

基于BISQ机制,推导了双相各向同性介质中弹性波数值模拟方程,并借助交错网格有限差分方法进行了波场模拟。证实了三种波(快纵波、慢纵波、横波SV)的存在和波场特征;在合成地震记录中,观测列三种波的反射,由于各种波相互之间的转换,转换波在地震记录中显示也很清楚,这使得波场变得更为复杂化。     

Transient bifurcation condition of partially saturated porous media at finite strain

Bifurcation of unsaturated soils into a localized shear band is a ubiquitous failure mode of partially saturated soils. The density and degree of saturation have major impacts on the inception of localized deformations in unsaturated soils. Unsaturated fluid flow may dramatically change the density and degree of fluid saturation of unsaturated soils. Therefore, the unsaturated fluid flow is a potential trigger for shear banding in such materials. In this paper, we derive a simplified bifurcation condition of localized deformation in unsaturated soils under the local transient condition at finite strain. This transient bifurcation condition is implemented into a nonlinear finite element code to study the inception of localized deformation in unsaturated soil specimens. Numerical simulations are conducted to study the impact of soil fabrics of density, a ‘bonding’ variable, and intrinsic permeability on the inception of localized failures via the transient bifurcation criterion. Mesh sensitivity analysis is performed to demonstrate the viscosity effect of unsaturated fluid flow on the localized deformation. Numerical simulations demonstrate that the transient bifurcation condition can detect the localized deformation triggered by the internal unsaturated fluid flow process in unsaturated soils. Copyright © 2016 John Wiley & Sons, Ltd.     

融合多模态特征的社会多媒体谣言检测技术研究

以微博为代表的社会媒体的蓬勃发展在加速信息交流的同时,也促使虚假谣言信息迅速在社会网络上传播,造成严重的后果.自动谣言检测问题受到了国内外学术界、产业界的广泛关注.围绕社会多媒体谣言检测这一问题,本文总结了融合多模态特征的谣言检测相关技术.首先从基本概念出发,阐述了谣言的定义和社会多媒体的特点,给出了社会多媒体谣言检测问题的定义.针对谣言检测面临的多模态特征抽取和模型构建两大难点,分别总结和归纳了各种类型的特征及其提取方法和不同的机器学习检测模型.这些特征和算法是检测谣言的基本手段,也是接下来研究的基础,可为进一步谣言检测的研究提供参考.     

多孔介质非饱和导水率预测的分形模型

多孔介质非饱和导水率是地下水污染预测与评价的重要参数。根据分形几何的基本原理和方法,推导出了与Campbell经验公式在形式上完全一致的多孔介质非饱和导水率的预测公式。公式中的幂指数为介质孔隙分维和随机行走分维的函数,分别体现了多孔介质的静态性质与动态性质对其中水分运动的影响,但静态性质的影响是主要的,即导水率主要受多孔介质的结构控制。根据文献中报道的大量数据,利用笔者推导的预测公式计算得到的幂指数的统计值与试验测定的幂指数的统计值基本一致,说明推导的理论公式预测多孔介质非饱和导水率是较为可靠的。