地质导向技术在煤层气水平井中的应用——以柳林区块某多分支水平井为例

地质导向技术能有效提高煤层气水平井施工成功率和煤层钻遇率,但由于其具有导向参数多、工艺要求高、易受地质因素影响等特点,使其在实际应用中还存在诸多难点。以柳林区块内某多分支水平井为例,针对该井现场地质导向作业面临的资料缺乏、参数受欠平衡钻进干扰、煤层结构复杂等难点,建立合适的地质导向模型,优选合理的导向参数和导向系统,对地质导向技术在实际应用中的工艺与流程进行了系统论述。实践表明,地质导向技术在该井的应用效果良好:煤层钻遇率达到了93.1%;截至目前,该井的产气量达8600m3/d,且还在进一步提升。     

Application of rock mass index (RMi) to the rock mass excavatability assessment in open face excavations

Earthwork and surface excavation activities play an important role in construction projects. Selecting the best technique to loosen the overburden material within the surface excavation in open mining and geotechnical projects is of great importance from economical and technical viewpoints. Surface excavation includes direct digging, ripping and blasting. To select the most effective method and plan for excavation, geotechnical investigation is very important. It is also a big help in avoiding conflict between contractors and clients when they do not reach mutual agreement regarding the price of rock and soil excavation. There are many engineering classification systems used to assess rock masses for excavation purposes. All of these systems consider several geotechnical parameters to assess the earth masses. This study reviews these systems and then offers a new categorization based on the Rock Mass index (RMi) classification system and block volume to assess excavation in rock masses. The original dataset was obtained from the literature review as well as the surface excavation in Upper Gotvand dam and Hydro Power Plant (HPP). The offered system was also validated through the data extracted from the surface excavation in Sardasht dam and HPP in Iran.     

拉萨地块西段典中组火山岩岩浆作用过程及其地质意义

拉萨地块西段分布有大面积的古近纪火山岩,蕴含着丰富的地质信息。文章对措勤地区典中组火山岩年代学、地球化学的研究表明,典中组火山岩岩浆活动在晚白垩世晚期已经开始,之后逐步向东迁移,时间上一直持续到古新世。印度板块与亚洲板块碰撞可能是从西段开始的,之后逐渐向东碰撞过渡。典中组火山岩岩浆形成的过程中发生了部分熔融作用,且在成岩过程中发生了混合作用;典中组火山岩是岛弧型俯冲向碰撞过渡过程中产生的具有岛弧或陆缘弧特点的火山岩。     

轨道约束的资源三号标准景影像区域网平差

考虑到同轨道拍摄的长条带卫星影像具有相同的误差分布特性,针对资源三号的标准景影像产品,提出了基于轨道约束的卫星影像区域网平差方法。首先,根据同轨相邻影像的偏移量计算轨道影像坐标系下的像点坐标;其次,通过同轨每景影像的RFM重新生成轨道影像的RFM,同时生成补偿格网;然后,根据基于像方仿射变换的RFM对轨道影像进行区域网平差;最后,利用求得的轨道影像的仿射变换参数重新计算原始单景影像的仿射变换参数。利用不同地区资源三号测绘卫星影像数据的试验表明,基于轨道约束的卫星影像区域网平差（以下简称轨道平差）在稀疏控制条件下,其精度明显好于单景影像平差的精度。在6控情况下,太行山试验区达到平面2.504m高程3.117m,在渭南试验区达到了平面4.061m高程2.895m。试验结果证明了轨道平差的有效性和可行性。     

大兴安岭北段塔源二支线铅锌铜矿区岩浆岩岩石成因及其地质意义

塔源二支线铅锌铜矿床地处额尔古纳地块东南缘,位于得尔布干成矿带东段.为确定塔源二支线铅锌铜矿区岩浆岩的岩石成因及其地质意义,对矿区岩浆岩开展了岩石学、地球化学以及同位素年代学研究.笔者在矿区识别出两期岩浆作用,早期发生于(296.1±2.3)Ma(早二叠世),侵入体为二长闪长岩;晚期发生在(136.5±2.1)Ma(早...     

遂昌麻车─后山垵糜棱岩的发现及其意义

作者在野外工作中，于遂昌─大柘变质岩断块（下称遂昌变质岩断块）北西侧，麻车─后山垵等地的地表或探矿巷道内，相继发现了多处糜棱岩化岩石露头，认为这一带存在一条较大的韧性剪切带。经对该带的地质，地球化学及金银矿分布的特征的综合分析研究，指出该韧性剪切带有关的金银矿化活动可分为两个期次，即早期金在韧性剪切活动中初始富集，晚期的脆性变形在局部地段形成金矿体。提出在该韧性剪切带找矿工作中，应重视继承韧性剪切带的脆性断裂和断裂带内的浅色蚀变组合及矿化特征。     

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Efficient block preconditioners for the coupled equations of pressure and deformation in highly discontinuous media

Large‐scale simulations of flow in deformable porous media require efficient iterative methods for solving the involved systems of linear algebraic equations. Construction of efficient iterative methods is particularly challenging in problems with large jumps in material properties, which is often the case in geological applications, such as basin evolution at regional scales. The success of iterative methods for this type of problems depends strongly on finding effective preconditioners. This paper investigates how the block‐structured matrix system arising from single‐phase flow in elastic porous media should be preconditioned, in particular for highly discontinuous permeability and significant jumps in elastic properties. The most promising preconditioner combines algebraic multigrid with a Schur complement‐based exact block decomposition. The paper compares numerous block preconditioners with the aim of providing guidelines on how to formulate efficient preconditioners. Copyright © 2010 John Wiley & Sons, Ltd.     

Stone run (block stream) formation in the Falkland Islands over several cold stages,deduced from cosmogenic isotope (10Be and 26Al) surface exposure dating

Cosmogenic isotope (¹⁰Be and ²⁶Al) surface exposure dating has been applied to valley‐axis and hillslope stone runs (relict periglacial block streams) and their source outcrops in the Falkland Islands, South Atlantic. The data indicate that stone runs are considerably older landforms than previously envisaged and afford no evidence that they are a product of the Last Glacial Maximum; the samples range in apparent ¹⁰Be age from 42k to 731k yr BP, but some of these are minima. The results indicate that valley‐axis stone runs may be up to 700–800k yr old, have simple exposure histories and are composite landforms that developed over several cold stages. Analyses of some hillslope and outcrop samples also demonstrate simple exposure histories with ¹⁰Be ages from 42k to 658k yr BP. In contrast, isotopic ratios from other hillslope and outcrop samples reveal they have had a complex exposure history involving periods of burial or shielding; the samples range in ¹⁰Be age from 59k to 569k yr BP and these are regarded as minimum age estimates. Larger stone runs may be older than smaller runs and there is a possibility that stone runs older than 800k yr exist in other parts of the Falklands. The assertion that glaciation in the Falklands was restricted to the highest uplands is supported by the data, and the potential for age determination of other boulder‐strewn and bedrock landforms, using cosmogenic isotope analysis, in order to extend the geochronology of Quaternary events and processes is noted. Copyright © 2008 John Wiley & Sons, Ltd.     

Effect of growing watershed imperviousness on hydrograph parameters and peak discharge

An increasing impervious area is quickly extending over the Wu‐Tu watershed due to the endless demands of the people. Generally, impervious paving is a major result of urbanization and more recently has had the potential to produce more enormous flood disasters than those of the past. In this study, 40 available rainfall–runoff events were chosen to calibrate the applicable parameters of the models and to determine the relationships between the impervious surfaces and the calibrated parameters. Model inputs came from the outcomes of the block kriging method and the non‐linear programming method. In the optimal process, the shuffled complex evolution method and three criteria were applied to compare the observed and simulated hydrographs. The tendencies of the variations of the parameters with their corresponding imperviousness were established through regression analysis. Ten cases were used to examine the established equations of the parameters and impervious covers. Finally, the design flood routines of various return periods were furnished through use of approaches containing a design storm, block kriging, the SCS model, and a rainfall‐runoff model with established functional relationships. These simulated flood hydrographs were used to compare and understand the past, present, and future hydrological conditions of the watershed studied. In the research results, the time to peak of flood hydrographs for various storms was diminished approximately from 11 h to 6 h in different decrements, whereas peak flow increased respectively from 127 m³ s^?1 to 629 m³ s^?1 for different storm intensities. In addition, this study provides a design diagram for the peak flow ratio to help engineers and designers to construct hydraulic structures efficiently and prevent possible damage to human life and property. Copyright © 2007 John Wiley & Sons, Ltd.