Experimental simulation on oil–water–rock interaction in deep zones

One-dimensional experimental simulation is carried out to study the mechanism of oil migration and accumulation in deep zones, the changes in the fluid components caused by oil–water–rock interaction during the process of fluid migration and the effect of the changes on reservoirs under certain temperature and pressure. The result shows that under certain temperature and pressure, many changes, which include their chemical components and the inner structure of rocks etc., occurred during oil migration from the bottom upwards along the experimental apparatus with the increased charging amount of crude oil. Especially, the biomarkers and mass composition of all samples derived from experiment unveil the existence of geochromatographic effect during the oil migration. And the dissolution has acted on mineral composition of oily-sands during the oil–water–rock interaction, which strengthens gradually during hydrocarbon migration from the bottom up along the apparatus.     

Numerical simulation of attenuation and group velocity of guided ultrasonic wave in grouted rock bolts

In this paper, the guided ultrasonic wave propagating in grouted rock bolts was simulated with finite element method. An 800 mm partially grouted cylindrical rock bolt model was created. Dynamic input signals with frequency from 25 to 100 kHz were used to excite ultrasonic wave. The simulated waveform, group velocity and amplitude ratio matched well with the experimental results. This model made it possible to study the behaviour of the guided waves in the grouted bolt along its central axis. Analysis of the simulated results showed that the group velocity in grouted rock bolts is constant along the grouted length, and the boundary effect on the group velocity is negligible. This paper also presents methods to determine the attenuation coefficient from simulation and to determine the boundary effect on attenuation at the bolt ends. The analysis showed that the attenuation of the guided wave propagating inside the grouted bolts is similar to the theoretical solution in steel bar with infinite length. After correction for the boundary effects the grout length of a grouted rock bolt can be determined using the measured attenuation, with sufficient accuracy.     

SPH-based numerical investigation of mudflow and other complex fluid flow interactions with structures

The understanding of mudflow–structure interactions and debris–flow structure interactions is of paramount importance for the rational design of technical countermeasures. However, to date, only a limited number of studies have investigated this subject. We propose here a numerical approach to this topic using a 2D vertical numerical model based on the smoothed particle hydrodynamics (SPH) method. First, we will test the capacity of the model to simulate unsteady free-surface flows of water and viscoplastic fluid in comparison to laboratory experiments. Then, we will use it prospectively, based on a series of simulations of Bingham fluid free-surface propagations, to determine the momentum reduction resulting from the presence of a simple obstacle perpendicular to the direction of propagation and to determine the characteristics of stresses applied to this obstacle in terms of peak pressure and evolution over time.     

城市平面坐标系建立方法探讨

本文在边长的高程归化以及边长的高斯投影改化详细分析的基础上,从变更中央子午线和投影面入手,对城市坐标系建立的方法进行了对比分析。     

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浙江省大气扩散能力的时空分布特征

利用以美国环保部推荐的经典高斯扩散模型为基础建立的大气扩散能力定量评估方法,研究浙江省大气扩散能力分布及年际变化特征。研究结果表明,浙江省大气扩散能力呈北部较南部强、沿海较内陆强的分布特点,不同设区市大气扩散指数从大到小的顺序为舟山(3.25)>台州(2.69)>嘉兴(2.22)>宁波(2.19)>衢州(1.75)>金华(1.70)>绍兴(1.67)>湖州(1.46)>杭州(1.34)>温州(1.27)>丽水(0.59)。不同时间尺度大气扩散能力特征为:7月大气扩散指数最大,达到4.19,2月最小,为1.51;夏季大气扩散指数最大,为3.37,秋季次之,为2.73,春季第三,为2.44,冬季最小,为1.94;1980—2014年年均大气扩散指数呈明显的下降趋势,下降了1.40,下降幅度达到58.33 %,而且2000年之后的下降速率较之前大。不同设区市大气扩散指数年际变化特征存在较大差异,表现最明显的有:温州地区大气扩散指数下降幅度最大,舟山地区大气扩散指数虽然一直较其它地区大,但近几年下降幅度比较大;丽水地区大气扩散指数一直最小,但其降幅也最小。      

BCC_CSM1.1(m)模式对初夏东北冷涡的模拟及应用

利用1991-2017年BCC_CSM1.1（m）模式模拟数据和NCEP/NCAR逐月再分析资料,评估了BCC_CSM1.1（m）对初夏东北冷涡的模拟能力。结果表明：BCC_CSM1.1（m）模式可以对500 hPa位势高度场气候态进行模拟,均方根误差显示该模式对中国东北南部地区500 hPa位势高度场的模拟要优于东北北部地区。EOF第一模态结果显示,该模式可以较好地模拟出500 hPa位势高度场的主要时空变化特征。BCC_CSM1.1（m）模式能够模拟出近27 a东北冷涡指数的上升趋势和年际变化,但模拟的上升趋势较实况偏强,年际变率较实况偏弱。BCC_CSM1.1（m）模式能够模拟出东北冷涡指数的年代际突变,但是对突变开始时间的模拟较实况偏晚。BCC_CSM1.1（m）模式能够模拟出东北冷涡指数和500 hPa位势高度场在东北及其附近地区的显著正相关,不能模拟出东北冷涡指数与东北初夏降水之间的显著负相关。此外,模式东北冷涡指数对东北初夏降水的预测能力十分有限。     

一种基于分布差异的分形网络演化分割方法

针对分形网络演化多尺度分割方法对高分辨率遥感影像存在的欠分割问题,文章提出以KL散度为核心的区域合并标准,研究出一种基于KL散度原理的改进分形网络演化多尺度分割方法。该方法相对于分形网络演化多尺度分割方法,在合并标准上更充分利用了遥感影像的光谱特征,能够很好地消除因光谱差异造成的欠分割,对同质性较强的地物效果尤为明显。通过WorldView-2高分辨率影像分割实验,比较欠分割率,结果证明该方法更适合于高分辨率遥感影像分割,能够为地物信息提取提供与自然更吻合的实体对象。     

Simulation and analysis of infrastructure interdependencies using a Petri net simulator in a geographical information system

Society relies greatly upon infrastructure networks that are highly interconnected and mutually dependent in complex ways. Simulation and modeling assist in dealing with the complexity of infrastructure networks, especially in the effective response and management of resources for rescue, recovery, and restoration. This paper introduces the Petri net into a geographical information system to develop the GeoPetri Net system, which can be used to simulate the complex geographical relationships among places and nodes. Unlike the ordinary Petri net, the GeoPetri Net deals with places and nodes with geographical locations and the geographical relationships between these nodes and records the statuses of nodes to produce simulated events. A case study involving an education layer with 15 nodes (schools) and a transportation layer with 25 node lines (streets) in a geographical information system is presented to substantiate the above conceptual arguments.     

广州平面坐标到1980西安坐标的转换方法研究与实现

根据我国多种坐标系统共存的现实,结合生产实际需求,研究了一种利用不同坐标系公共点确定广州坐标系到1980西安坐标转换的实用方法。这种实用方法的特点是充分考虑广州坐标系统的独特性,提出了广州平面坐标到西安80坐标转换的坐标转换技术方案。同时,开发了实用方便的计算软件。通过算例证明了该方法的可行性和可靠性。