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232.
非开挖水平定向钻进软件设计研究 总被引:1,自引:0,他引:1
轨迹设计是非开挖水平定向钻进管线铺设施工的关键。本文应用动态规划原理, 对轨迹最优化设计进行了深入研究。根据工程实际需要, 设计出一套水平定向钻进软件, 实现了轨迹最优化设计、施工图设计、竣工图处理、施工记录表填写及轨迹查询等功能, 集设计、优化、出图于一体。实践证明, 该软件能很好地满足水平定向钻进工程的要求。 相似文献
233.
WU Weiwei LONG Feng LIANG Mingjian WEI Yaling SUN Wei CHEN Xuefen ZHAO Jing 《《地质学报》英文版》2020,94(5):1635-1650
As a case study of spatial and temporal variations in earthquake stress drops between the 2008 Ms 8.0 Wenchuan and 2013 Ms 7.0 Lushan earthquakes, we computed 1828 stress-drop values for earthquakes with magnitudes 1.7 ≤ ML ≤ 5.0 during an eight-year time span before and after major earthquakes. We divide the study area into three subregions (the southern segment of the Longmen Shan fault zone; the southwestern junction of the Longmen Shan and Sichuan Basin; and the southwestern margin of the Sichuan Basin) and calculate individual event stress drops in each. The results show that regions of alternating high and low stress drop are found on either side of the southwestern segment of the Longmen Shan fault zone. During the two-year period after the 2008 Ms 8.0 Wenchuan earthquake, the stress state of the southern Longmen Shan fault shows no significant change. A marked increase in stress level appears about 18 months before the 2013 Ms 7.0 Lushan earthquake near the Lushan hypocenter zone. Two months after the Ms 7.0 event, the stress drops suddenly attenuate, with significantly less seismic energy release per event. We find that changes in the patterns of high and low stress drop values are consistent with the process of stress accumulation or transfer from the pre-mainshock to post-mainshock periods. The results indicate that major earthquakes are the dominant cause of temporal and spatial evolution in stress levels. Stress drop variations show obvious temporal and spatial patterns that may suggests subtle changes in the character of stress fields on faults and spatial variations related to local intense compression and tectonic effects. 相似文献
234.
作为深海科学研究的重要基础装备,深海超长沉积物柱状取样系统在海底地形地貌、海洋地质构造、气候环境变化等研究领域发挥了重要作用,其在海底矿产资源勘探、海洋工程地质勘察等方面展现了巨大应用价值。针对传统超长柱状沉积物取样系统在作业过程中存在的盲目采样、安全隐患大、甲板作业空间受限等问题,自主研制了一套适用于深海的超长可控可视沉积物柱状取样系统,该系统具有液压锤击、立式收放和实时监控功能,能获取连续、超长、具有精准姿态方位信息的柱状沉积物样品。现通过对独立排缆方式、取样管快速拆装、样品封堵、低扰动取样刀头等关键技术细节进行优化,解决了样品扰动大、取样率低的问题,提高了取样作业效率与样品质量,且降低了作业安全风险。2017—2021年,该取样系统搭载不同母船在南海1 700,1 725 和1 778 m水深分别获取了15.25、16.01和15.83 m的长柱状沉积物样品。该设备的成熟应用,可为我国深海探测研究提供技术支持。 相似文献
235.
WANG Lan-sheng WANG Xiao-qun SHEN Jun-hui YIN Guan CUI Jie XU Xiang-ning ZHANG Zhi-long WAN Tao WEN Li-wang 《山地科学学报》2020,17(5):1172-1187
In 1999, Diexi paleo-dammed lake(2349 m a.s.l.) was discovered around Diexi town along the Minjiang River in Sichuan province. Diexi is located where the eastern edge of the Tibetan Plateau and the Sichuan Basin meet. The dammed lake was formed during the Last Glacial Maximum of the Late Pleistocene(~30,000 years ago) and began to empty about 15,000 years ago. The lacustrine sediments(up to 240 m thick) preserve abundant paleoenvironment information. In this paper, a mass of oxygen isotopes and 14 C dating from drilled cores are analyzed and discussed. The δ18 O curve on the paleo climate from this section is comparable with the coeval paleo climatic curves of ice cores and karsts in China and others. Furthermore, the physical model testing has confirmed that the disturbed zones in the core are caused by strong earthquakes occurred at least 10 times, which implies strong crustal deformation, as an important driving force, affecting climate change. This study provides a new window to observe East Asian monsoon formation, paleoenvironmental evolution and the global climate change. 相似文献
236.
Niobium (Nb) in carbonatite is mainly hosted in fluorcalciopyrochlore and columbite-(Fe). Information related to Nb petrogenesis is useful for understanding the processes related to Nb mineralization and carbonatite evolution. The Saint-Honoré, Quebec, alkaline complex offers a rare opportunity for studying these processes as the complex is not affected by post-emplacement deformation, metamorphism nor weathering. Columbite-(Fe) is shown to be an alteration product of fluorcalciopyrochlore (columbitization). Columbitization is characterized by the leaching of Na and F from the A- and Y-sites of the pyrochlore crystal structure. As alteration increases, Fe and Mn are slowly introduced while Ca is simultaneously leached. Leached Ca and F then crystallize as inclusions of calcite and fluorite within the columbite-(Fe). A-site cations and vacancies in the crystal structure of fresh and altered pyrochlores demonstrate that pyrochlore alteration is hydrothermal in origin. Moreover, halite is a ubiquitous mineral in the Saint-Honoré alkaline complex. Petrographic evidence shows that halite forms in weakly altered pyrochlores, suggesting halite has a secondary origin. As alteration increases, halite is expelled by the hydrothermal fluid and is carried farther into the complex, filling factures throughout the carbonatite. The hydrothermal hypothesis is strengthened by significant enrichments in Cl and HREEs in columbite-(Fe). Chlorine is most likely introduced by a hydrothermal fluid that increases the solubility of REEs. 相似文献
237.
Mountain glacier-related hazards occur worldwide in response to increasing glacier instability and human activity intensity in modern glacierized regions. These hazards are characterized by their spatial aggregation and temporal repeatability. Comprehensive knowledge about mountain glacier-related hazards is critical for hazard assessment, mitigation, and prevention in the mountain cryosphere and downstream regions. This article systematically schematizes various mountain glacier-related hazards and analyzes their inherent associations with glacier changes. Besides, the processes, manifestations, and mechanisms of each of the glacier-related hazards are summarized. In the future, more extensive and detailed systematic surveys, for example, considering integrated ground-air-space patterns, should be undertaken for typical glacierized regions to enhance existing knowledge of such hazards. The use of coupled numerical models based on multi-source data is challenging but will be essential to improve our understanding of the complex chain of processes involved in thermal-hydrogeomorphic glacier-related hazards in the mountain cryosphere. 相似文献
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239.
钟凌林 钟康惠 秦覃 严钊 杨雄 何智远 张洪杰 彭杰 Johan De GRAVE Stijn DEWAELE 周慧文 何兴杰 韩文文 龚晓波 杨海锐 董随亮 常宇鹏 李开智 窦杰 李林 何明峰 刘毅龙 《地学前缘》2022,29(1):266-284
雅鲁藏布江洋俯冲及印度-欧亚陆陆碰撞导致了强烈的大陆岩石圈挤压变形与青藏高原的隆升。研究青藏高原内部破碎带构造-沉积演化,对理解相关变形如何向欧亚大陆腹地扩展传递至关重要。班公湖—怒江缝合带内发育一系列白垩纪—新生代陆相沉积盆地,保存了关于该时期高原内部构造-沉积演化的丰富信息。针对该类盆地的构造性质和形成机制有走滑拉分盆地、断陷盆地、前陆盆地3类不同观点。若要检定上述观点,需要开展如下工作:(1)查明盆地基底与充填建造变形特征;(2)结合构造背景探究其演化机制。鉴于此,本文对该带内尼玛盆地开展大比例尺地质填图与构造分析,结合前人成果,对盆地构造背景、构造性质和构造演化进行了探讨。主要取得了如下认识:(1)尼玛盆地基底为班公湖—怒江洋闭合形成的软碰撞缝合带内的变质岩与海相沉积岩。基底断裂为近东西走向,倾向或南或北的逆冲断裂。(2)盆地充填建造为上白垩统—新近系多旋回河湖相沉积。其变形样式主要为轴向近东西延伸的非对称褶皱,局部卷入基底断裂变形。多幕次变形自边缘向盆地中心前展式递进发展。(3)盆地可以划分为盆北掀斜隆起、南部推覆扇状隆起两处主要剥蚀物源区、中部基底断片掀斜隆起一处次要剥蚀物源区,以及北部叠瓦状压陷区与南部对冲压陷区两处主要构造沉积单元,其构造格架可以概括为“三隆夹两坳”。(4)尼玛盆地肇始于班公湖—怒江洋闭合导致的南北向地壳缩短。其后,雅鲁藏布江洋北向俯冲与印度-欧亚碰撞所致南北向挤压,导致盆地基底断裂发生周期性活动,伴有多旋回磨拉石建造与递进变形。简言之,尼玛盆地为软碰撞缝合带之上发育的山间压陷盆地。 相似文献
240.
水平井分段多簇压裂是非常规油气藏开发的关键技术,在合理利用压裂诱导应力增大储层改造体积的同时,避免井间干扰所导致的裂缝砂堵和压裂窜扰,是压裂工艺优化中的关键科学问题。文章针对超临界CO2分段多簇压裂的缝间干扰和井间干扰问题,采用流固耦合的扩展有限元方法研究单井及多井裂缝诱导应力演化特征,充分考虑裂缝内超临界CO2流动和滤失,从非常规油气储层岩性特征、地应力场分布及施工工艺等多方面对压裂扰动应力进行系统研究,揭示单井分段多簇压裂缝扩展机制及应力扰动特征,在此基础上研究多井井间压裂缝干扰规律。结果表明:高水平应力差、高弹性模量的储层中压裂干扰界限较大,低水平应力差、低弹性模量地层需适度增大簇间距,减小簇间干扰;老井压裂后,其邻井压裂缝非对称系数随井间距呈先增大、后减小的趋势;当井间距等于压裂干扰界限时,非对称系数λ达到最大,且井周改造范围最大,但裂缝两翼的非对称性可能导致储层动用不充分。本研究为水平井细分切割压裂和立体式井网设计优化提供理论基础,在“双碳”战略背景下对非常规油气资源高效开发具有重要意义。 相似文献