鄂尔多斯盆地东南部山西组泥岩封盖性能评价     

李亚龙  于兴河  单新  王娇  史新  胡鹏 《吉林大学学报(地球科学版)》2017,47(4)

为弥补鄂尔多斯盆地东南部盖层的研究空白,借鉴已有研究成果与盖层基本特征,选取泥岩孔隙度、渗透率、厚度以及排替压力4个参数,结合灰色理论分析方法,对鄂尔多斯盆地东南部山西组泥岩盖层封盖性能进行了综合定量评价。结果表明:盆地东南部泥岩北东部较厚,整体呈从北向南减薄的趋势,南部孔隙度及渗透率均偏高;泥岩盖层排替压力较大,大于8 MPa的平面面积占70%以上;由灰色理论打分评价可知,山西组整体盖层封盖性能较好,封盖能力特强(Ⅰ类盖层)、封盖能力强(Ⅱ类盖层)的盖层分布区域广泛,Ⅰ类和Ⅱ类盖层主要发育于盆地北部、北东部,中部延长、延安、志丹等周边地区,盖层封盖性好,Ⅲ类盖层(封盖能力中等)、Ⅳ类盖层(封盖能力差)主要发育于南部。盖层发育较好的地区,经勘探开发与试气,单井日产量可达上万方,证明评价结果与勘探实践匹配。  相似文献   

塔里木盆地西南地区早中寒武世岩相古地理     

姜海健  储呈林  杨鑫  陈强路  岳勇  邵志兵 《海相油气地质》2017,22(1)

塔里木盆地西南地区早中寒武世岩相古地理存在一定争议,这制约了该区的勘探评价。综合利用露头、钻井和地震资料,开展沉积相、地震相分析,并结合区域构造背景,恢复了岩相古地理格局,提出了相应的沉积模式。中下寒武统发育陆棚相、开阔台地相、局限台地相、蒸发台地相和缓坡相。震旦纪末期麦盖提斜坡南部形成水下低隆起,向南在西南坳陷区残留部分被动陆缘,主要发育缓坡相、陆棚相;麦盖提斜坡区地势较高,地层较薄,主要发育局限台地和蒸发台地潮坪;巴楚隆起区水体局限,在干燥炎热气候下形成了厚度较大的蒸发台地膏盐湖沉积。巴楚隆起区和麦盖提斜坡区中下寒武统膏盐岩分布广泛,与下伏碳酸盐岩可构成良好的储盖组合,西南坳陷区残留部分被动陆缘,烃源岩发育条件较好,这表明塔西南具有较好的油气前景。  相似文献   

Discrimination of sand dunes and loess deposits using grain-size analysis in northeastern Iran     

Alireza Karimi  Farhad Khormali  Xin Wang 《Arabian Journal of Geosciences》2017,10(12):275

Identification and characterization of aeolian deposits in arid environments provide information on mechanisms of loess and sand accumulation. The objectives of this study were to (i) identify the distribution of aeolian deposits, (ii) discriminate loess and sand deposits using granulometric data, and (iii) describe the aeolian deposition in Sarakhs area, northeastern Iran. Particle size distributions of 26 surface samples were determined using a laser grain-size analyzer. Fine sand, very fine sand, and very coarse silt were dominant fractions in studied sediments, and the sum of these fractions ranged from 46.9% in loess deposits to 93.8% in sand dunes. The mean grain size (M _z ) of sand dunes ranged from 3.31 to 3.54 ?, which gradually changed to 4.09 to 5.50 ? in loess deposits. Sorting, skewness, and kurtosis ranged from 0.84 to 1.94 ?, 0.18 to 0.49, and 0.76 to 2.38, respectively. Aeolian deposits in the area resulted in the incorporation of Hariroud River system and Kopeh Dagh Mountains for aeolian particle production and accumulation. Alluvial comminution in Hariroud River is suggested the main mechanism of sand and silt production and flood plain environment the main reservoir of these particles. The mountains of Kopeh Dagh act as a barrier and play a key role for sand and loess accumulation.  相似文献   

Experimental study on the instability mechanism of the major-defect fractured rock     

Yajun Xin  Mengyuan Li  Dingchao An  Hongying Ji  Jichun Kang 《Arabian Journal of Geosciences》2017,10(14):311

Based on calculations of rock fracture surface and angle, incremental-load creep experiments were conducted on two groups of major-defect fractured rock specimens in an RLW-2000 rheology test system. The research investigated the fracture type and the creep properties of major-defect fractured rock and analyzed the relationships between failure load and horizontal or vertical projection distance, and between each of theme and fracture area or angle. The results showed that rock fracture was divided into three types according to the distribution, including I, II, and III types. I, II, and III types were respectively an internal fracture running through neither the upper nor lower end, one through the upper or lower end and one through both upper and lower ends, and a III type was further sub-divided into III_I and III_II types. The instantaneous strain was larger than the creep strain under the same creep loading stage. As the creep loading increased on two groups of major-defect fractured rock, the instantaneous strain decreased abruptly and then increased abruptly, while the creep strain decreased rapidly at first and later increased near-linearly. When the failure angle was larger than the friction angle, failure load was positively correlated with failure angle yet was negatively correlated with vertical projection distance. Vertical projection distance and fracture angle, which decided fracture type, controlled rock failure load. Failure load increased in turn from I type to III type, and low-type fracture determined mainly failure load in multiply-fracture specimen.  相似文献   

Isotope evidence for quantifying river evaporation and recharge processes in the lower reaches of the Yellow River   总被引：1，自引：0，他引：1  

Xin Zhao  Fadong Li 《Environmental Earth Sciences》2017,76(3):123

Evaporation and recharge are important hydrological processes in the water cycle. However, accurately quantifying these two processes of river remains to be difficult due to their spatial heterogeneity and the limitations of traditional methods. In this study, a more reliable method of stable isotopes of δ ¹⁸O and δ ²H based on the Rayleigh distillation equation and mass conservation was used to estimate the evaporation and recharge of the rivers in the lower reaches of the Yellow River, North China Plain. Comprehensive sampling campaigns including 30 surface water samples from 10 rivers, 33 groundwater samples from domestic and observation wells, and two Yellow River water samples were conducted. The results showed that the evaporation proportion of the rivers based on δ ¹⁸O and δ ²H both averaged 14.4%. The evaporation proportions in each river did not completely follow a linear increasing trend along the flow path. This phenomenon could be mainly explained by the different proportions of recharge from groundwater and Yellow River water. With closer to the Yellow river, evaporation of the rivers decreased while the recharge by the Yellow River increased. Regression equations based on δ ¹⁸O, δ ²H, and their average revealed that the evaporation proportion respectively increased by 1.02, 0.79, and 0.90% with the increase in the distance to the Yellow River per 10 km. On the contrary, the recharge proportion decreased by 7.68, 5.51, and 6.59%, respectively. In addition, using δ ¹⁸O rather than δ ²H was more reliable in studying the spatial influence of the Yellow River on evaporation and recharge. Sensitivity analysis showed that the evaporation model was most sensitive to isotopic composition, rather than to air temperature or relative humidity. The results of this study provide insights into the determination of river hydrological processes and the management of water resources.  相似文献   

Stress distribution characteristic analysis and control of coal and gas outburst disaster in a pressure-relief boundary area in protective layer mining     

Zhen Liu  He Yang  Weimin Cheng  Lin Xin  Guanhua Ni 《Arabian Journal of Geosciences》2017,10(16):358

Coal and gas outburst disasters in coal seams are becoming more serious as coal mines extend deeper underground in China. Furthermore, the protective coal seam mining technology featured by economic efficiency has been proven to be the most effective and widely applied method for the prevention of coal and gas outburst disasters. However, the determinations of the protective area coal and gas outburst prevention in a pressure-relief boundary area are fundamental issues that research should be focused on. The technical method for determining stress distribution in pressure-relief boundary area during protective coal seam mining is put forward in this paper. The method is based on a stress-seepage coupled relationship within a gas-containing coal seam. The method includes complex lab experiments and on-site measurements at the Qingdong Coal Mine. The final data illustrate that the permeability and vertical stress in the pressure-relief boundary area of the coal sample form a negative exponential function relationship. Additionally, the permeability of the coal sample within the abovementioned area is significantly different compared with that located at the center of the pressure-relief area. In the pressure-relief boundary area, the gas pressure distribution gradient is 0.0375 MPa/m, while the vertical stress distribution gradient registers 0.56 MPa/m. Under this condition, coal and gas outburst disasters are prone to be triggered. Therefore, effective precautions against coal and gas outburst disasters can be put forward in accordance with stress distribution characteristics within the abovementioned “boundary area.”  相似文献   

南方复杂地形条件下1∶5万重力调查成果分析——以江西甲路幅为例   总被引：2，自引：1，他引：1       下载免费PDF全文

赖发腾  郭信  周月  张小龙  赵宝峰 《华东地质》2017,(4):255-263

文章对江西甲路幅1∶5万重力调查实测数据进行处理与解释,推断并构建了甲路幅断裂构造体系,解释了主要断裂的形态、延伸及性质。结合磁测异常圈定了研究区内的隐伏岩体,并通过2.5D解释确定了主要岩体的外接触面形态与埋深;通过对区域典型矿床地质、物化探异常特征研究,结合地质、化探资料对该区成矿远景进行圈定与预测。通过研究构造、岩体、成矿三者之间的关系,认为断裂控制岩浆与热液的运移,进而控制隐伏岩体及内生型金属矿床的发育与空间展布。与其他物探方法相比,重力调查在解释断裂构造方面具有自身特色与优势,是配合矿产地质调查查明断裂、隐伏岩体及隐伏矿床的最佳物探方法之一。  相似文献   

川南沐川地区宣威组底部铌-稀土多金属富集层富集规律、沉积环境与成矿模式     

文俊  刘治成  赵俊兴  竹合林  张航飞  张金元  陈东方  钟海仁  郭文彦  游学军  赵伟  凌茂前  李鹏程  何永刚 《地质学报》2022,96(2):592-615

云南、贵州地区对晚二叠世宣威组底部Nb-REE多金属富集层的研究取得了重要进展,但其成因还有较大争议.为厘清沐川地区宣威组底部Nb-REE多金属富集层成因机制及富集规律,本研究开展了野外实地调查、矿物学、岩相古地理与岩石地球化学等系统性研究,探讨其物源、富集规律,建立了成矿模式.结果 表明,川南沐川地区宣威组底部Nb-...  相似文献   

中纬热层大气质量密度经向结构差异研究          下载免费PDF全文

王慧  张科灯  万欣 《地球物理学报》2016,59(10):3573-3579

本文利用CHAMP卫星以及全球电离层-热层模型(GITM)来研究太阳活动低年(2007—2009年)中纬热层大气质量密度(ρ)的经度结构变化.结果如下:(1)ρ存在明显的经度单波结构(单峰和单谷),且南北半球反相,波峰和波谷随着地方时增加而向东移动;(2)模拟表明离子拖曳效应在ρ结构差异的形成中起到了重要的作用,欧亚地区电子密度经度差异性较弱,不足以影响ρ经度分布,导致该地区ρ经度差异不明显;(3)在磁中纬地区,太阳天顶角的经度差异可达20°~30°,太阳光加热的经度不均匀性是导致ρ经度差异的另一个主要原因.  相似文献   

基于瞬变电磁矩变换的快速三维反演方法   总被引：1，自引：0，他引：1       下载免费PDF全文

饶丽婷  武欣  吴超  张晓娟  方广有 《地球物理学报》2016,59(11):4338-4348

瞬变电磁法的严格三维反演计算复杂、占用资源多,在普通计算机上难以实现.本文引入瞬变电磁矩变换的概念,提出一种快速三维反演方法.该方法基于阻性限制(resistive limit)特性,建立包含异常体的三维大地的一阶矩响应正演算法,根据不同约束条件,选择优化的最速下降法实现瞬变电磁快速三维反演.文中通过含异常体的三维大地正演一阶矩与仿真数据一阶矩的对比,验证了快速三维正演算法的有效性,之后在不同约束条件下,利用优化的最速下降法实现了对含噪声的仿真瞬变电磁数据的快速三维反演.结果表明,该方法能够在普通计算机上短时间内较为准确地反演出地下异常体的体积和位置,在瞬变电磁数据的实时解释工作中具有良好的应用前景.  相似文献