Mechanism of strata deformation under protective seam and its application for relieved methane control     

Wei Yang  Bai-quan Lin  Yong-an Qu  Shuai Zhao  Cheng Zhai  Li-li Jia  Wu-qiang Zhao 《International Journal of Coal Geology》2011,85(3-4):300-306

In this paper, an equation correlated with normal stress and permeability was developed and FLAC^3D software was used to investigate the rock mass stress evolution and distribution to understand the methane flow characteristics. Research results show that the rock mass under the protective coal seam can be divided into three belts (zones) in the vertical direction, including total de-stressed belt, vertical de-stressed belt and original stress belt. Methane in the total de-stressed belt can flow into the working face of protective coal seam by its own pressure gradient. Methane in the vertical de-stressed belt can only be extracted by boreholes. In the horizontal direction, the rock mass was also divided into five zones, including original zone, compression zone, expansion zone, recovering zone and re-compacted zone, which have been proved correct by the field experiments. The rock mass permeability in the de-stressed belts doesn't increase until stepping into the expansion zone, and from then on higher concentration of methane can be extracted. The methane in original regions is difficult to extract because rock stresses stay the same. The division of “three belts and five zones” reveals the rock mass stress and permeability distribution and evolution and supplies theoretical guidance for relieved methane control.  相似文献   

U–Pb and Re–Os geochronology and geodynamic setting of the Dabaoshan polymetallic deposit, northern Guangdong Province, South China     

Lei Wang  Mingan Hu  Zhen Yang  Wenjun Qu  Jinlong Xia  Kaixu Chen 《Ore Geology Reviews》2011,43(1):40-49

The Dabaoshan polymetallic deposit in northern Guangdong Province contains iron, copper, lead, zinc, molybdenum, tungsten and sulfur mineral resources. Porphyry-type Mo(W) and skarn-type Mo-W mineralization occurs along the internal and external contact zones of the granodioritic porphyry, respectively. LA-ICP-MS U–Pb dating of zircons from two granodioritic porphyry samples yielded a weighted mean ²⁰⁶Pb/²³⁸U age of 175.8 ± 1.5 Ma (MSWD = 0.037) and 175.0 ± 1.7 Ma (MSWD = 0.41). They can be pooled together to yield a combined weighted age of 175.4 ± 1.6 Ma (MSWD = 0.26), which is interpreted as the emplacement age of the granodioritic porphyry. Re–Os dating of three molybdenite samples from porphyry and skarn ores yielded consistent model ages of 163.2 ± 2.3 Ma to 165.2 ± 2.4 Ma, with a weighted mean of 163.9 ± 1.3 Ma (MSWD = 0.81), which is the age of Mo–W mineralization. These ages are consistent with the molybdenite Re–Os model age (164.7 ± 3 Ma) measured by Mao et al. (2004a) for the stratiform Cu–Pb–Zn orebody, and they can yield a weighted mean of 164.0 ± 2.5 Ma (MSWD = 0.16). This implies that Mo–W and Cu–Pb–Zn mineralization in the Dabaoshan polymetallic deposit are the products of one mineralization event. The mineralization in the deposit coincides closely with that of Mo-polymetallic mineralization (164–149 Ma) elsewhere in the Nanling region, comprising an important polymetallic metallogenic belt of south China, and corresponds to the second episode of Mesozoic metallogenesis in South China. Combined with previous studies, we suggest that the Dabaoshan polymetallic deposit is related to post-collisional lithosphere extension in the Nanling region of South China. Geological data and Pb isotopic evolution diagrams, together with stable isotopic data of fluid inclusions (δ¹⁸O = − 3.75–7.0‰, δD = − 50.7 to − 56.1‰) and ore sulfides (δ³⁴S = − 2–3‰), suggest a genetic relationship between the Dabaoshan polymetallic deposit, the granodioritic porphyry and the dacitic porphyry. These data, combined with the Re content (64.7 to 102.4 ppm) of molybdenite, indicate that the ore-forming components were derived from mixed crustal and mantle sources.  相似文献   

DN630供水管道定向钻穿越淮河工程的设计和施工     

朱旋  屈学平 《岩土钻凿工程》2011,(2):11-14

作为非开挖施工的一个分支,定向钻穿越技术得到了越来越广泛的应用。本文以DN630供水管道定向钻穿越淮河工程为例,介绍了定向钻穿越的技术特点,指出了设计基本原则及设计要素如管道钻进的入土角、出土角、曲率半径和穿越深度等确定方法,并阐述了定向钻穿越施工工艺流程及泥浆配制、钻导向孔、扩孔及管道回拖等主要施工工艺。  相似文献   

西藏嘎拉勒夕卡岩型金（铜）矿床地球化学特征与锆石的LA-ICP-MS定年及意义   总被引：4，自引：0，他引：4  

吕立娜  崔玉斌  宋亮  赵元艺  曲晓明  王江朋 《地学前缘》2011,18(5):224-242

嘎拉勒金（铜）矿床位于西藏班公湖—怒江缝合带的西段,为夕卡岩型金（大型）铜（小型）矿床。矿区主要岩石为巨斑状石英闪长岩、中细粒花岗闪长岩与闪长玢岩。该矿床岩石样品的REE分异程度较高,Eu呈弱负异常,w（Al2O3）为14.45%～15.84%,铝过饱和指数A/CNK为1.33～1.46,均大于1,表明为S型花岗岩。经...  相似文献   

Source characteristics of the Yutian earthquake in 2008 from inversion of the co-seismic deformation field mapped by InSAR     

Xinjian Shan  Guohong Zhang  Chisheng Wang  Chunyan Qu  Xiaogang Song  Guifang Zhang  Liming Guo 《Journal of Asian Earth Sciences》2011,40(4):935-942

On 21 March 2008, an Ms7.3 earthquake occurred at Yutian County, Xinjiang Uygur Autonomous Region, which is in the same year as 2008 Mw 7.9 Wenchuan earthquake. These two earthquakes both took place in the Bayar Har block, while Yutian earthquake is located in the west edge and Wenchuan earthquake is in the east. The research on source characteristics of Yutian earthquake can serve to better understand Wenchuan earthquake mechanism. We attempt to reveal the features of the causative fault of Yutian shock and its co-seismic deformation field by a sensitivity-based iterative fitting (SBIF) method. Our work is based on analysis and interpretation to high-resolution satellite (Quickbird) images as well as D-InSAR data from the satellite Envisat ASAR, in conjunction with the analysis of seismicity, focal mechanism solutions and active tectonics in this region. The result shows that the 22 km long, nearly NS trending surface rupture zone by this event lies on a range-front alluvial platform in the Qira County. It is characterized by distinct linear traces and a simple structure with 1–3 m-wide individual seams and maximum 6.5 m width of a collapse fracture. Along the rupture zone are seen many secondary fractures and fault-bounded blocks by collapse, exhibiting remarkable extension. The co-seismic deformation affected a big range 100 km × 40 km. D-InSAR analysis indicates that the interferometric deformation field is dominated by extensional faulting with a small strike-slip component. Along the causative fault, the western wall fell down and the eastern wall, that is the active unit, rose up, both with westerly vergence. The maximum subsidence displacement is ～2.6 m in the LOS, and the maximum uplift is 1.2 m. The maximum relative vertical dislocation reaches 4.1 m, which is 10 km distant from the starting rupture point to south. The 42 km-long seismogenic fault in the subsurface extends in NS direction as an arc, and it dipping angle changes from 70° near the surface to 52° at depth ～10 km. The slip on the fault plane is concentrated in the depth range 0–8 km, forming a belt of length 30 km along strike on the fault plane. There are three areas of concentrating slip, in which the largest slip is 10.5 m located at the area 10 km distant from the initial point of the rupture.  相似文献   

世界主要深水含油气盆地烃源岩特征   总被引：2，自引：1，他引：1  

范玉海  屈红军  张功成  冯杨伟  关利群  雷露 《海相油气地质》2011,16(2):27-33

对墨西哥湾、巴西东部大陆边缘、西非被动大陆边缘、澳大利亚西北陆架、挪威中部陆架、南海等六个地区的22个深水含油气盆地烃源岩特征(主力烃源岩形成的时代、构造背景、沉积环境、类型、地球学化指标等)的综合研究结果表明,世界深水含油气盆地主力烃源岩主要集中在白垩系,其次为第三系和侏罗系;裂谷期烃源岩占绝对优势,其次为被动陆缘期...  相似文献   

深水平台吸力沉箱基础工程地质问题分析     

曲延大  王建华 《海洋技术学报》2011,30(1):72-77

针对深水平台吸力沉箱基础,讨论了与沉箱安装有关的分析方法及涉及的工程地质参数,分析了承受竖向拉拔荷载、倾斜与水平荷载作用的吸力沉箱极限承载力的分析方法及涉及的工程地质参数,对与吸力沉箱设计有关的其它问题也进行了分析.在此基础上,阐明了与吸力沉箱设计有关的工程场地调查内容及需要确定的工程地质参数.其目的是为开发深水平台吸...  相似文献   

二连盆地早白垩世断陷及基底构造的耦合性   总被引：3，自引：0，他引：3       下载免费PDF全文

李先平  张少华  李林波  杨明慧  卢永合  周多  屈晓艳 《地质科学》2015,50(1):88-99

基底构造在沉积盆地的形成与演化过程中扮演着重要的角色。本文利用地球物理资料和地表地质调查数据,对二连盆地早白垩世断陷分布规律与基底构造特征及其关系进行了研究,并分析了基底构造对富油凹陷的控制作用。结果表明,二连盆地早白垩世68个断陷总体上自北东向南西呈弥散式分布,这些断陷可分为南部断陷群与北部断陷群,断陷群夹持在隆起之间,总体上构成了正负相间的盆岭构造格局。基底构造控制着二连盆地早白垩世断陷分布,表现为:断陷群沿着深断裂分布;坳陷对应着基底先存复向斜,隆起对应着基底先存复背斜;刚性的锡林浩特地块分割了断陷群。深断裂作为构造薄弱区在伸展变形过程中优先重新活动,并控制着断陷的发育与分布;盖层演化和基底构造之间具有良好的继承性;基底流变性发生突变的区带对断陷的发育与分布也具有控制作用。盆地基底断裂带上叠的凹陷、基底断裂带交汇处上叠的凹陷和刚性基底上新生的凹陷在伸展变形过程中构造继承性好、沉降量大、优质烃源岩发育,是富油凹陷发育的有利区域。  相似文献   

An Review of International Climate Change Conference and Analysis on Recent Hot Issues     

Zeng Jingjing  Qu Jiansheng  Pei Huijuan  Dong Liping  Liao Qin  Liu Yanfei  Zhang Zhiqiang 《地球科学进展》2015,30(11):1210-1217

The international climate change negotiation has been carried out over 20 years. The issue of climate change has shifted from a scientific question into a complex political matter which is related to the sustainable development of mankind. Based on the overview of major processes and stages of international climate conferences, this paper analyzed the key measures that major countries have taken to address climate change, as well as the primary tasks of Paris climate conference and recent international actions. The recent international climate policy issues were also analyzed in order to provide suggestions for China’s activel participation in the development of a new round of international climate change system.  相似文献   

Evolution process of sediment supply for debris flow occurrence in the Longchi area of Dujiangyan City after the Wenchuan earthquake     

Ming Chang  Chuan Tang  Huayong Ni  Yongping Qu 《Landslides》2015,12(3):611-623

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