高分辨率反射波地震勘探在城市隐伏断裂探测中的应用——以成都天府新区苏码头断裂为例     

刘远志  刘胜  李大虎  夏友钢  李颖  周德帅 《大地测量与地球动力学》2019,39(9):910-915

采用“三小三高二绝招”的工作方法，通过静校正、多域多方法联合噪音衰减和精细的速度分析获得较高分辨率的地震时间剖面，揭示苏码头断裂的展布位置、构造形态及变形样式等。结果表明，区域构造以冲起式为主，在反冲断层与逆冲断层之间形成冲起构造或逆冲三角构造，在地震剖面上有明显的楔状特征。通过地震测线的断层走向以NE为主，倾向以SE为主，部分断层倾向为NW。  相似文献   

Pricing Weather Derivatives Index based on Temperature: The Case of Bahir Dar,Ethiopia     

Tesfahun BERHANE  Aemiro SHIBABAW  Gurju AWGICHEW 《资源与生态学报(英文版)》2019,10(4):415-423

In this paper we present a stochastic model for daily average temperature to calculate the temperature indices upon which temperature-based derivatives are written. We propose a seasonal mean and volatility model that describes the daily average temperature behavior using the mean-reverting Ornstein-Uhlenbeck process. We also use higher order continuous-time autoregressive process with lag 3 for modeling the time evolution of the temperatures after removing trend and seasonality. Our model is fitted to 11 years of data recorded, in the period 1 January 2005 to 31 December 2015, Bahir Dar, Ethiopia, obtained from Ethiopia National Meteorological Services Agency. The analytical approximation formulas are used to price heating degree days (HDD) and cooling degree days (CDD) futures. The suggested model is analytically tractable for derivation of explicit prices for CDD and HDD futures and option. The price of the CDD future is calculated, using analytical approximation formulas. Numerical examples are presented to indicate the accuracy of the method. The results show that our model performs better to predict CDD indices.  相似文献   

A finite element approach for predicting the full resistance profile of a spudcan deeply penetrating in dense sand overlying clay     

《Applied Ocean Research》2019

This paper presents a finite element approach to calculate the full resistance profile of a spudcan deeply penetrating in dense sand overlying clay, in which a potential for an installing spudcan to experience a sudden uncontrolled punch-through failure exists. A modified Mohr-Coulomb model characterized by incorporating a four-phase variation of the mobilized strength and dilation parameters with an equivalent accumulated plastic strain is developed and tested for the overlying dense silica sand. An extended Tresca model is used for the strain softening of the underlying clay. A series of large deformation finite-element (LDFE) analyses are carried out, varying the strength and dilation parameters as well as the spudcan geometries. A fairly good performance of the present approach is verified by validating against groups of centrifuge tests data, allowing the numerical study to be extended parametrically. The four-phase variation of the mobilized strength and dilation parameters involved in the progressive failure of the upper dense sand is parametrically studied and extended to cover the range of sand relative densities that are of practical interest. Additionally, comparisons with the typical existing LDFE analyses using both simple and sophisticated constitutive models are carried out. It shows that the present approach performs fairly well to calculate the full resistance profile of a spudcan deeply penetration in both thin and thick dense sand overlying clay, especially the peak and post-peak resistance, within around 5% of the corresponding centrifuge tests results.  相似文献   

改进的最小曲率迭代法在重力剖面数据插值中的应用     

朱文武  彭军还  高艳龙  李方舟  贾玥 《大地测量与地球动力学》2019,39(8):810-812

基于将约束点也作为待解算结点的思想，对传统最小曲率迭代法进行改进。改进后的方法在待解算结点周围存在约束点时，避免了根据约束点与待解算结点之间的不同关系需要进行分类推导的复杂过程，同时也避免了因使用泰勒展开式进行分解造成的精度损失，提高了解算精度。  相似文献   

Modification and discussion of the Green-Ampt model for an evolving wetting profile   总被引：1，自引：0，他引：1  

Qiyong Zhang  Yuzhen Kong 《水文科学杂志》2020,65(12):2072-2082

ABSTRACT

The Green-Ampt (GA) model has been widely used to evaluate soil water infiltration. While a simple piston profile is commonly used, the wetting profile of a soil changes during infiltration and a quarter-ellipse has been found to better describe its evolution. This study aims to improve the GA model and discuss the model parameters when the quarter-ellipse profile is utilized. The soil column is divided into three zones: saturated, transient and dry. The variable γ is introduced to express the ratio of the saturated zone depth to the wetting front depth. A modified GA model is derived via mathematical methods, but an exact solution is difficult to obtain. Therefore, a simplified (SGA) model is developed via a segmented method. Compared with the measured results, the SGA model is more accurate than the traditional model. Finally, the model parameters are discussed and a value of γ = 0.5 is recommended.  相似文献   

黄土高原沟谷地貌发育演化研究进展与展望     

熊礼阳  汤国安 《地球信息科学学报》2020,22(4):816-826

黄土沟谷是黄土地貌中最有活力、最具变化、最富特色的对象单元,黄土高原千沟万壑的地貌形态以及触目惊心的侵蚀状态也让区域内沟谷地貌的形成、发育及演化问题成为研究中焦点及前沿性科学问题。近年来,诸多学者采用地学测年法、特征表达法、监测模拟法力图实现对黄土沟谷发育演化进程中“过去-现代-未来”的科学认知。这些研究在相当程度上丰富了黄土沟谷发育过程的认知。本文梳理了黄土高原沟谷地貌演化相关研究的现状,并从黄土高原地貌演化、黄土沟谷发育、基于DEM的沟谷信息提取与表达等研究进行了系统的回顾、梳理与分析。此外,本文提出“黄土沟道剖面群组”概念与方法,试图从新的视角审视黄土沟谷地貌发育演化过程。沟道剖面在黄土沟谷发育演化进程中传递物质能量和累积地形动力,并通过径流节点的串联实现剖面群的连接与组合,形成独特的剖面“群组”模式;该沟道剖面群组是集黄土沟谷地貌特征与过程于一体的综合信息集成体,其三维空间结构是对黄土沟谷地貌发育演化的高度抽象与映射,并可望进一步丰富黄土高原数字地形分析理论与方法体系,为黄土高原黄土地貌成因机理与空间分异格局带来创新的认识。  相似文献   

Granite is an Effective Helium Source Rock: Insights from the Helium Generation and Release Characteristics in Granites from the North Qinling Orogen, China     

ZHANG Wen  LI Yuhong  ZHAO Fenghu  ZHOU Zheng  HAN Wei  ZHOU Junlin  ZHANG Qiao 《《地质学报》英文版》2020,94(1):114-125

Global helium(He) shortage is a challenging problem; however, the types of helium source rock and the mechanisms of He generation and release therein remain still poorly understood. In this study, in order to evaluate the potential of granite as an effective helium source rock, we collected granitic samples from the North Qinling Orogen, Central China, in the south of the helium-rich Weihe Basin. The helium generation and release behaviors in granite were studied through analysis of U and Th concentrations, EMPA images, and He and Ar concentrations and isotopic ratios extracted by crushing and stepwise heating. The results indicate that Ar has a better retention and a lower mobility than He. 3 He/4 He ratios released by crushing and stepwise heating are 0.016–0.056 RA and 0.003–0.572 RA, respectively, where RA is the atmospheric 3 He/4 He of 1.4×10-6, reflecting a crustal and radiogenic source. Helium concentrations extracted by the two ways are 0.13–0.95 ucm3 STP/g and 7.82–115.62 ucm3 STP/g, respectively, suggesting that matrix-sited He accounts for more than 98% of total helium preserved in granite. In addition, the total generated He amounts in granites are calculated based on the measured U and Th concentrations in granitic samples. Dividing the preserved He quantities by the generated He amounts, it turned out that less than 10% of He produced since the formation of the granite is preserved in the rock over geological time, suggesting that more than 90% generated He can be transferred to the Weihe Basin. Temperature and fracture are the two critical factors controlling He release. Based on the relationship between He diffusivity of granites and temperature and the He closure temperatures of a variety of U-and Th-rich minerals(27–250°C), we estimate that He can be partially released out of granite at the depths 400 m and totally released at the depths 7800 m. Fractures provide effective transfer of free He from deep source rocks to shallow reservoirs. Finally, a model on granite as an effective helium source rock is established. We suggest exploring He resources in hydrocarbon basins with granitic basement(or adjacent to granite bodies), high geothermal field, and young active fractures.  相似文献   

基于高导热材料填充漏失构造的深井换热器性能分析   总被引：1，自引：0，他引：1  

卜宪标  蒋坤卿  李华山  王令宝 《地质学报》2020,94(7):2139-2146

地热供暖可有效缓解北方雾霾天气。干热岩虽然储量丰富，但增强型地热技术由于开发费用较高，裂隙控制以及避免诱发地震的技术尚不成熟，现阶段还不能商业化应用。水热型地热开发技术虽较成熟，但受资源条件的限制，开发规模较小。对于大多地区，受地质构造和资源禀赋的控制，单井产水量较低或者回灌难，开发经济效益较差。深井换热器（DBHE）技术是开采地热水低产区或回灌难地区热能的有效方式，但受制于岩石导热系数低，单井输出功率小，投资回收期长。为提高DBHE的输出功率，本文提出了增强型深井换热器（EDBHE），通过主动将高导热性能的复合填充剂流进漏失构造的方式提高岩石的导热性能，通过调节回压、密度和黏度来控制漏失量。研究结果表明，单井EDBHE十个采暖季的平均取热功率为1002. 34 kW，是DBHE(424. 45 kW)的2. 36倍。而双井EDBHE十个采暖季的平均取热功率更是达到了27501. 61 kW，且热输出稳定，每年的衰减率0. 95%。EDBHE技术有效利用了出水量低或回灌难的水热型热储，大幅提高了其出力，扩大了地热供暖的应用范围。  相似文献   

煤层气井产出剖面测试技术及应用     

张雷  樊洪波  侯伟  张伟  郝帅  孙晓光 《吉林大学学报(地球科学版)》2020,50(2):617-626

现有常规油气井产出剖面测试方法在煤层气井中适应性较差，测试范围和测量工艺等存在局限性，施工成功率低。因此，本文对煤层气井产出剖面测试技术进行了整体的系统化设计和研发。通过紧凑的结构设计、高度集成，研发了一套可同时进行温度、压力、磁性定位、热式流量、探针持气率、微波持气、涡轮流量和超声流量等多参数测量的煤层气井测井仪，并研制了一套一次下井可进行多种测试技术测量的煤层气井产出剖面测试技术。同时提高了测试仪器的精度和抗干扰能力，开发了多任务多窗口的便携地面系统操作，并研制新型偏心测试井口应用于煤层气井，实现修井作业时不间断连续测试。该技术在鄂尔多斯盆地石楼北区块3口煤层气井进行了现场试验，取得精确、连续的测试数据。测试结果显示，石楼北区块8^#+9^#煤层为主力产气、产水层。  相似文献   

Evaporation of the Nerve Agent GB From Common Matrices: A Model‐System Study          下载免费PDF全文

Ishay Columbus  Itzhak Marcovitch  Shlomi Elias  Lea Yehezkel  Dana Marder  Victoria Nahum 《洁净——土壤、空气、水》2018,46(4)

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