Pore-Fracture Distribution Heterogeneity of Shale Reservoirs Determined by using HPMI and LPN2 GA Tests     

ZHANG Junjian  QIN Zhengyuan  HAN Yanning  WANG Huaimeng  HOU Maoguo  YAN Gaoyuan  FENG Guangjun  ZHANG Xiaoyang  YIN Tingting  ZHANG Hainan  WEN Shupeng 《《地质学报》英文版》2022,96(5):1659-1672

The compressibility of shale matrix reflects the effects of reservoir lithology, material composition, pore structure and tectonic deformation. It is important to understand the factors that influence shale matrix compressibility (SMC) and their effects on pore size distribution (PSD) heterogeneity in order to evaluate the properties of unconventional reservoirs. In this study, the volumes of pores whose diameters were in the range 6–100 nm were corrected for SMC for 17 shale samples from basins in China using high-pressure mercury intrusion and low-temperature nitrogen gas adsorption analyses, in order to investigate the factors influencing the SMC values. In addition, the variations in fractal dimensions before and after pore volume correction were determined, using single and multifractal models to explain the effects of SMC on PSD heterogeneity. In this process, the applicability of each fractal model for characterizing PSD heterogeneity was determined using statistical analyses. The Menger and Sierpinski single fractal models, the thermodynamic fractal model and a multi-fractal model were all used in this study. The results showed the following. The matrix compression restricts the segmentation of the fractal dimension curves for the single fractal Menger and Sierpinski models, which leads to a uniformity of PSD heterogeneity for different pore diameters. However, matrix compression has only a weak influence on the results calculated using a thermodynamic model. The SMC clearly affects the multifractal value variations, showing that the fractal dimension values of shale samples under matrix compression are small. Overall PSD heterogeneity becomes small for pores with diameters below 100 nm and the SMC primarily affects the PSD heterogeneity of higher pore volume areas. The comparison of fractal curves before and after correction and the variance analysis indicate that the thermodynamic model is applicable to quantitatively characterize PSD heterogeneity of shale collected from this sampling area. The results show that PSD heterogeneity increases gradually as micro-pore volumes increase.  相似文献   

胶东和鲁西金矿床空间分布分形差异及对金来源的启示     

朱平平  刘岳  成秋明 《矿床地质》2023,42(3):639-645

胶东和鲁西地体发育大量的中生代金矿床,其金元素的来源一直是学术界争论的焦点,可能的来源方式为：交代岩石圈地幔、前寒武纪变质基底和中生代二长花岗岩。为了进一步厘定金的来源,文章从金的富集阶段模式和金矿床是金元素超常富集地质体的思想出发,运用金矿床的空间分布数据和空间分析的分形地质统计方法,进行了研究。研究结果发现,胶东金矿床（N=823）具有一阶段的空间分形分布模式,其分形维数α=0.726,具有单一来源或单一成因的特征;结合前人研究和克拉通破坏和西太平洋俯冲的地质背景,推断胶东金元素极有可能是单一的交代岩石圈地幔来源;而胶东地体西侧鲁西地体中发育的金矿床（N=139）则具有二阶段的空间分形分布模式,其分形维数分别为α1=1.630和α2=0.850,具有2种金元素来源或2种成因类型的特征,可能分别对应着早前寒武纪变质岩及韧性剪切带有关金矿床和晚中生代岩浆活动有关金矿床空间分布的分形维数,后者的值与胶东地体的分形维数相近,结合前人研究,推测鲁西部分金矿床来源于交代岩石圈地幔的贡献,另一部分则可能来自于花岗质岩浆。  相似文献   

Structural Control on the Salmas Geothermal Region, Northwest Iran, from Fractal Analysis and Paleostress Data     

Mahdi BEHYARI  Javad NOURALIEE  Davar EBRAHIMI 《《地质学报》英文版》2018,92(5):1728-1738

The Salmas geothermal field is located in NW Iran. Subduction of Neo-Tethys oceanic crust beneath the Iranian microcontinent caused to propagation of the magmatic-Arc. Fractures and faults in the convergent zone have created path-ways for the circulation of geothermal fluid. Fracture concentration in the Salmas geothermal field has been characterized using of the fractal method and creation of a fracture density map that shows the highest concentration in the central part of the study area. The permeability of fractures has been evaluated by analyzing their orientation in respect to the paleostress axes. Also, the fractal analyzing result indicates the maximum fractal dimension (1.96) is around the thermal spring outlet. Paleostress analyzing revealed that in the central part of the study area, σ1 axes orientation is S90°W/10° and the σ2 dip is near to the vertical in this stress field, where strike slip faults can be propagated. In the SE part near the recharge of the thermal springs, the σ3 plunge increases to 70? and σ1 orientation is N15°E/20°, in this local tectonic regime thrust fault developed. Fractures have an important role in the circulation of fluid and the fractal dimension increases near the thermal springs in the Salmas geothermal field. Regarding the paleostress data fracture with N-S direction such as the F1 fault zone (parallel to the σ1 axes), a suitable pathway for deep circulation of geothermal fluid flow has been created.  相似文献   

分形校正理论在减弱物探数据体积效应中的应用     

崔健  殷梅  申维 《江苏地质》2018,42(3):401-406

野外物探工作采集得到的数据,是一定范围内地质体引起的地球物理场的综合反映。基于非线性科学的分形理论,建立测度与尺度之间的指数关系,构建分维数矩阵,达到对数据进行分形校正的目的。通过实例分析,阐述了覆盖区间的宽度对于分维数计算结果的影响及边界效应的变化规律。实测数据经分形校正处理后,可以最大程度地消除地球物理场中体积效应的影响,还原单个测点的真实值,即该测点下地质体所引起的地球物理场值,为分形校正方法的应用提供了理论支撑和案例参考。  相似文献   

Comparison of U-spatial statistics and C–A fractal models for delineating anomaly patterns of porphyry-type Cu geochemical signatures in the Varzaghan district,NW Iran     

《Comptes Rendus Geoscience》2018,350(4):180-191

The delineation of populations of stream sediment geochemical data is a crucial task in regional exploration surveys. In this contribution, uni-element stream sediment geochemical data of Cu, Au, Mo, and Bi have been subjected to two reliable anomaly-background separation methods, namely, the concentration-area (C–A) fractal and the U-spatial statistics methods to separate geochemical anomalies related to porphyry-type Cu mineralization in northwest Iran. The quantitative comparison of the delineated geochemical populations using the modified success-rate curves revealed the superiority of the U-spatial statistics method over the fractal model. Moreover, geochemical maps of investigated elements revealed strongly positive correlations between strong anomalies and Oligocene–Miocene intrusions in the study area. Therefore, follow-up exploration programs should focus on these areas.  相似文献   

青藏高原周边地区河流分形特征与地貌、构造活动耦合关系   总被引：3，自引：1，他引：2  

文力  魏鹏飞  常华进  孙小舟  李权国  杜红旺  刘琛  李学敏  秦玉莉 《地质通报》2018,37(6):965-974

青藏高原周边地区的地貌特征与形成演化机制一直是科学界研究的热点。选择青藏高原周边典型地区河流分形特征、地貌特征及构造活动性进行研究,发现喜马拉雅断裂带、龙门山断裂带和阿尔金断裂带控制的区域构造活动性强烈,历史地震记录频繁,大震较多,河流形态与地貌演化特征也非常相似,河流纵剖面变化很快,长波长下凹型,河流坡降比大,地形起伏度大,河流形态变化简单,河流分维值低;青藏高原东北缘构造活动性不强烈,历史地震记录偏低,大震极少,河流纵剖面变化缓慢,近似长波长微振幅上凸型,河流坡降比小,地形起伏度较小,河流形态错综复杂、分维值高;青藏高原东南缘,构造活动性较强烈,历史地震记录频繁,大震较多,但由于该区域平均多年侵蚀速率比较低,同时河流下切深度大,河流纵剖面变化缓慢,也是近似长波长微振幅上凸型,河流坡降比小,河网发育较成熟,河网分维值较高。通过对比发现,降水量的变化对该区域侵蚀速率的影响远小于构造活动性的作用,在分析河网形态特征时可以不考虑降水量空间变化的影响。  相似文献   

三峡库区岸坡消落带岩体劣化分形特征与演化预测研究     

闫国强  黄波林  殷跃平  胡雷  陈云飞 《地质学报》2023,97(7):2399-2407

三峡库区岸坡岩体劣化的关键在于岩体节理的持续扩展。本文采用分形理论对消落带上下岸坡测窗岩体劣化程度、劣化破碎相变时间及发展趋势进行了分析。研究表明：岩体节理劣化分布具有分形属性,可将缺项值Λ(r)曲线陡缓转折点视为REV(表征单元)岩体尺寸下限;整体来看,劣化使得岩体节理生长向更加均匀、密布的趋势发展,呈现升维特征;进一步利用节理升维值ΔDb建立了劣化程度分级标准,升维值ΔDb与面积节理数增量ΔJov、地质强度指标变化值ΔGSI满足指数函数关系;最后探讨并提出了2种节理分维数劣化演变模式,采用岩体劣化破碎相变时间计算式可进行相应的演化预测分析,且岩体劣化破碎相变时间预测是基于割线的估计。由于分维数Db具有较高的统计稳定性,能够满足工程应用需求。研究成果为库区岸坡劣化程度调查以及劣化演化预测提供了新的方法。  相似文献   

Fractal dimension estimations of drainage network in the Carpathian–Pannonian system   总被引：1，自引：1，他引：0  

Endre Dombrdi  Gbor Timr  Gbor Bada  Sierd Cloetingh  Frank Horvth 《Global and Planetary Change》2007,58(1-4):197

The development of drainage network in the intra-Carpathian realm is influenced by a complex Quaternary tectonic evolution manifested with differential vertical motions. The present-day configuration of the left-hand side tributary system of the Tisza river was studied by means of fractal analysis. Fractal dimensions describing the complexity of the network were obtained by different methods. These include the early estimations based on stream ordering hierarchy and the application of the box-counting and sandbox algorithms representing fixed-size algorithms considered as efficient tools in fractal set analysis. Besides calculations made for the entire drainage system, the region was subdivided into three distinct areas characterised by different Quaternary uplift history. These are the Apuseni Mts., the Transylvanian basin and a part of the Eastern Carpathians, investigated separately. The concept of multifractality was also taken into consideration and dimensions of both higher and lower orders were determined along with the corresponding singularity spectra. Non-space-filling and multifractal behaviour of the network structure was validated. However, small but tendentious variations of the support dimensions (D₀) were observed in the three sub-regions. The Transylvanian basin is characterised by the lowest estimated dimensions, while higher values represent the Apuseni Mts., and the western slopes of the Eastern Carpathians. In addition, fractal dimension values showed consistency within each sub-region. Correlation of these measures with average uplift rates was performed. As a major outcome, differential uplift, affecting the morphology of catchments, appears to influence the obtained fractal dimensions, whereas surface lithology conceivably plays only a secondary role.  相似文献   

闽台建设用地图像数据空间特征分形对比研究   总被引：1，自引：0，他引：1  

张金前  韦素琼  陈健飞  陈志强 《地球信息科学学报》2006,8(3):119-124

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。  相似文献   

遥感与GIS的青海湖岸线分维研究   总被引：2，自引：0，他引：2  

张灿龙  邓自旺  倪绍祥  胡颖文  陈健  刘振波 《地球信息科学学报》2006,8(4):141-145

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。  相似文献