Occurrence and influence of residual gas released by crush methods on pore structure in Longmaxi shale in Yangtze Plate,Southern China

The composition of gas released under vacuum by crushing from the gas shale of Longmaxi Formation in Upper Yangtze Plate, Southern China was systematically investigated in this study. The effect of residual gas release on pore structures was checked using low-pressure nitrogen adsorption techniques. The influence of particle size on the determination of pore structure characteristics was considered. Using the Frenkel-Halsey-Hill method from low-pressure nitrogen adsorption data, the fractal dimensions were identified at relative pressures of 0−0.5 and 0.5−1 as D₁ and D₂, respectively, and the evolution of fractal features related to gas release was also discussed. The results showed that a variety component of residual gas was released from all shale samples, containing hydrocarbon gas of CH₄ (29.58% −92.53%), C₂H₆ (0.97% −2.89%), C₃H₈ (0.01% −0.65%), and also some non-hydrocarbon gas such as CO₂ (3.54% − 67.09%) and N₂ (1.88%−8.07%). The total yield of residual gas was in a range from 6.1 μL/g to 17.0 μL/g related to rock weight. The geochemical and mineralogical analysis suggested that the residual gas yield was positively correlated with quartz (R²=0.5480) content. The residual gas released shale sample has a higher surface area of 17.20−25.03 m²/g and the nitrogen adsorption capacity in a range of 27.32−40.86 ml/g that is relatively higher than the original samples (with 9.22−16.30 m²/g and 10.84−17.55 ml/g). Clearer hysteresis loop was observed for the original shale sample in nitrogen adsorption-desorption isotherms than residual gas released sample. Pore structure analysis showed that the proportions of micro-, meso- and macropores were changed as micropores decreased while meso- and macropores increased. The fractal dimensions D₁ were in range from 2.5466 to 2.6117 and D₂ from 2.6998 to 2.7119 for the residual gas released shale, which is smaller than the original shale. This factor may indicate that the pore in residual gas released shale was more homogeneous than the original shale. The results indicated that both residual gas and their pore space have few contributions to shale gas production and effective reservoir evaluation. The larger fragments samples of granular rather than powdery smaller than 60 mesh fraction of shale seem to be better for performing effective pore structure analysis to the Longmaxi shale.     

地层含金性评价的分数维研究———以琼西抱板群为例

摘 要　 利用分形理论研究了琼西抱板群金含量分布的分数维结构特征‚并对其含金性作出 评价。结果表明‚较小的分维及具有多标度分形‚有利于金矿化的产出。     

水文地质参数优选的一维寻查法

介绍了一维寻查法的基本原理,并给出了应用实例;实现了计算机自动优选水文地质参数,改变了过去人工凋参的传统方法;同时也指出了该方法的局限性。      

Stock Evaluation of Three Littoral Echinoid Species on the Catalan Coast North-Western Mediterranean

Abstract. We estimated the abundances of the three common littoral echinoid species Paracentrotus lividus, Arbacia lixula and Sphaerechinus granularis in a littoral zone between 0 and 10m depth on the Catalan shores NE Spain. Densities of each species were estimated from a total number of 11 571× 1 m² sampling units deployed at 152 sites along the 13 zones into which the coast was divided. The surface area available in each of these zones was estimated at the scale of the sampling unit 1 m² taking into account the fractal dimension of the shore. The stocks individuals > 2cm test diameter of these species for the whole Catalan shore ≅ 300 km, straight-line distance were estimated to be about 279.1 × 10⁶ individuals for P. lividus , 28.9 × 10⁶ individuals for A. lixula and 10.9 × 10⁶ individuals for S. granularis. These sea-urchins are key species in the regulation of algal communities and some of them P. lividus. S. granularis are of commercial interest. This information will provide a tool for the future monitoring and management of this resource, which now faces diverse pressures of human origin.     

新构造分异的地学信息分析--以山东半岛北部为例

水系图像空间特征与几何空间特征是新构造运动地表综合信息的反映,也是区域新构造差异的两种新的分析手段。新构造运动差异分析表明,山东半岛新构造运动受控于西侧的郯(城)-庐(江)大断裂,次级的NE-NNE向断裂则控制了整个半岛地区的E-W向差异运动。以NE向青(岛)-牟(平)断裂束为界,分为东、西两个新构造活动亚区。西部相对东部在新构造时期抬升,相对抬升幅度达30m以上。     

遥感与GIS的青海湖岸线分维研究

讨论了TM图像以及分形几何学对青海湖岸线问题的求解算法,同时估算了不同像元尺度下,青海湖的岸线长度得出青海湖岸线的分形维数为1.0237,并探讨了其地学意义,研究表明,分形维数不仅是一种可行的表达岸线特征的方法,而且岸线分维数的计算可大大减少工作量和提高工作效率,可见遥感与GIS技术在岸线分维数的计算中,具有十分良好的应用前景。     

闽台建设用地图像数据空间特征分形对比研究

利用2002年闽、台ASTER影像数据,运用分形几何学理论、数理统计方法,对闽台建设用地分布的空间特征进行分析。研究结果表明,分维值是定量刻画土地利用类型空间格局的重要参数,对遥感影像中直接提取土地利用类型的图形因子进行不同区域土地利用分形结构的差异研究,具有快速、方便、准确的性质。闽、台建设用地斑块的空间分布具有分形特征,其空间形态受自然和人文两方面因素,特别是地形地貌和交通的影响十分明显。同时台湾建设用地的平均斑块面积、分维值和规模大的斑块比重均高于福建,反映了闽、台建设用地空间特征的区域差异,这对闽、台两地,特别是福建省加强建设用地规划,合理配置空间资源,及福建省加强中心城市建设和交通规划等方面具有重要的指导意义。     

流化床混凝装置中多级速度梯度的建立及其对混凝反应的影响

利用不同性质颗粒在流化状态下可实现自然水力分级的特征,在流化床反应器中沿水流方向实现了多级速度梯度的建立。在研究流化床混凝反应器的混凝动力学特征基础上,探讨了以800 μm和1 200 μm树脂颗粒为固相的多级速度梯度流化床（MGF）的速度梯度分布特征、混凝效率和絮体形态特征,并与以1 200 μm树脂颗粒为固相的单级速度梯度流化床（SGF）进行了对比研究。结果表明：与单级速度梯度相比,多级速度梯度可为胶体或微颗粒的高效碰撞和絮体再增长创造更适宜的环境,有助于形成尺寸更大、密度更大的絮体,提高了絮体的可沉降性;MGF在处理人工配置的高岭土悬浊液和分散红染料废水时,混凝效率比SGF分别提高了2%～4%和7%～20%。     

基于分形维数的湖州旅游景区系统空间结构优化研究

中小城市旅游业空间结构的优化及其与更大空间范围的旅游资源进行整合、衔接,是目前非中心旅游地区旅游资源开发和旅游业空间结构优化的难点。运用分形理论对湖州市旅游景区系统空间结构优化进行研究,聚集维数的测算显示湖州景区系统的空间分布聚集性较强,关联维数的测算结果显示其具有多分形特征。据此,湖州市旅游景区系统空间结构的优化主要为两个方面,即完善"两核心三组团"的旅游空间结构;加强"点—轴—面"交通体系建设,促进湖州接轨长三角地区旅游系统。     

辽西黄土湿陷变形特性及湿陷后微观结构变化

初始含水率对黄土湿陷性具有重要的影响。利用人工制备不同含水率的试样对辽西黄土的湿陷变形特性进行了试验研究,并采用SEM技术测试了黄土湿陷前后的微观结构变化,采用微结构定量化分析方法和分形几何方法分析了黄土试样微观孔隙的变化特征。结果表明：1)初始含水率对辽西黄土的湿陷变形具有显著的影响,随着试样初始含水率的增大,同一压力下的湿陷变形量越来越小;2)不同初始含水率试样的压力-变形关系曲线可以统一用双曲线形式表达;3)湿陷后黄土试样的结构变得较为致密,孔隙总数显著增加,而孔隙面积减小。湿陷过程主要是小孔隙数量增加、孔隙形状分维数减小、孔隙复杂程度显著增加的过程。