苏北复杂断裂带成藏规律研究与目标评价

苏北盆地是江苏油田最重要的采油区和探油区，自“九五”末期以来，勘探效益有所下降，表现在有利储备圈闭缺乏、后备储量跟不上、接替区带不明朗、勘探形势较为严峻。为了尽快摆脱这种不利局面，有必要加大复杂断裂带等领域的研究力度，争取在新层系、新类型、新领域找到突破口。本论文对苏北盆地高邮、金湖凹陷复杂断裂带成藏规律进行了深入细致的分析研究，运用多学科、多理论、多方法，重点对高邮金湖地区复杂断裂带的构造样式、构造演化、油气成藏要素（油源、储层、盖层及疏导体系）、断裂对油气运移、沉积、圈闭形成和油气保存的控制作用、油藏分布及成藏模式等问题进行了全面、系统的研究，对断裂带构造格局、油气成藏规律有了新的认识。论文取得的主要成果如下： 1．通过区域资料分析和石港、铜城、杨村、汉留、真武等复杂断裂带特征及形成机制研究认为金湖—高邮凹陷是区域右行剪切力偶作用下形成的张扭性凹陷，发育帚状、雁列状、入字型、梳状和花状等张扭性构造样式和阶梯状、垒堑状、Y字型等伸展构造样式。 2. 分析了真②断层间构造调节带，汉留－吴②构造调节带、真武断裂系-吴堡断裂系构造调节带、吴堡构造调节带、卞闵杨构造调节带的类型、空间形态和石油地质意义。 3．对断裂坡折带的类型以及断裂坡折带与沉积体系和砂体分布规律进行了研究。将凹陷分为凸起－陡坡边缘坡折带、陡坡－洼陷边缘坡折带、凸起－缓坡边缘坡折带和缓坡－洼陷边缘断裂坡折带等类型。 4．高邮—金湖凹陷油气分布及富集规律表现为深大断裂大多为油气通道，油气具有沿生油中心呈环带状分布和沿着油源断裂带状分布的特征；张扭性构造样式对圈闭形成、油藏分布具有控制作用。 5．根据油气运移主方向可以将油气成藏模式划分为侧向运移成藏模式和垂向运移成藏模式。侧向运移成藏模式主要发育于高邮凹陷北斜坡、韦庄地区和金湖凹陷西斜坡、闵桥等地区。垂向运移成藏模式主要发育于高邮金湖凹陷陡坡带，又根据断裂带的特征进一步划分为金湖陡坡带成藏模式和高邮陡坡带成藏模式。 6．综合复杂断裂带构造样式、调节带特征、坡折带类型和成藏控制因素的分析，认为卞闵杨地区和真武－汉留断阶带调节构造圈闭发育，是今后勘探构造油气藏的重点区块；陡坡－洼陷边缘坡折带和缓坡－洼陷边缘坡折带是滑塌浊积砂体等优质储层发育区，是寻找岩性隐蔽油藏有利区。如真②断层下降盘和三河次凹西斜坡等地区。

Impacts of land use change and climate variations on annual inflow into Miyun Reservoir,Beijing, China

The Miyun Reservoir, the only surface water source for Beijing city, has experienced water supply decline in recent decades. Previous studies suggest that both land use change and climate contribute to the changes of water supply in this critical watershed. However, the specific causes of the decline in the Miyun Reservoir are debatable under a non-stationary climate in the past 4 decades. The central objective of this study was to quantify the separate and collective contributions of land use change and climate variability to the decreasing inflow into the Miyun Reservoir during 1961–2008. Different from previous studies on this watershed, we used a comprehensive approach to quantify the timing of changes in hydrology and associated environmental variables using the long-term historical hydrometeorology and remote-sensing-based land use records. To effectively quantify the different impacts of the climate variation and land use change on streamflow during different sub-periods, an annual water balance model (AWB), the climate elasticity model (CEM), and a rainfall–runoff model (RRM) were employed to conduct attribution analysis synthetically. We found a significant (p  <  0.01) decrease in annual streamflow, a significant positive trend in annual potential evapotranspiration (p  <  0.01), and an insignificant (p  >  0.1) negative trend in annual precipitation during 1961–2008. We identified two streamflow breakpoints, 1983 and 1999, by the sequential Mann–Kendall test and double-mass curve. Climate variability alone did not explain the decrease in inflow to the Miyun Reservoir. Reduction of water yield was closely related to increase in actual evapotranspiration due to the expansion of forestland and reduction in cropland and grassland, and was likely exacerbated by increased water consumption for domestic and industrial uses in the basin. The contribution to the observed streamflow decline from land use change fell from 64–92 % during 1984–1999 to 36–58 % during 2000–2008, whereas the contribution from climate variation climbed from 8–36 % during the 1984–1999 to 42–64 % during 2000–2008. Model uncertainty analysis further demonstrated that climate warming played a dominant role in streamflow reduction in the most recent decade (i.e., 2000s). We conclude that future climate change and variability will further challenge the water supply capacity of the Miyun Reservoir to meet water demand. A comprehensive watershed management strategy needs to consider the climate variations besides vegetation management in the study basin.

Nanoscopic modelling of the adhesion, indentation and fracture characteristics of metallic systems via molecular dynamics simulations

Large-scale molecular dynamics simulations have been performed on canonical ensembles to model the adhesion and indentation characteristics of 3-D metallic nano-scale junctions in tip-substrate geometries, and the crack propagation in 2-D metallic lattices. It is shown that irreversible flows in nano-volumes of materials control the behaviour of the 3-D nano-contacts, and that local diffusional flow constitutes the atomistic mechanism underlying these plastic flows. These simulations show that the force of adhesion in metallic nano-contacts is reduced when adsorbate monolayers are present at the metal—metal junctions. Our results are in agreement with the conclusions of very accurate point-contact experiments carried out in this field. Our fracture simulations reveal that at low temperatures cleavage fractures can occur in both an elemental metal and an alloy. At elevated temperatures, the nucleation of dislocations is shown to cause a brittle-to-ductile transition. Limiting crack propagation velocities are computed for different strain rates and a dynamic instability is shown to control the crack movement beyond this limiting velocity, in line with the recent experimental results.

Fracture mechanics analysis of cracks in solder joint intermetallic compounds

The trend towards miniaturization of electronic products leads to the need for very small sized solder joints. Therefore, there is a higher reliability risk that too large a fraction of solder joints will transform into Intermetallic Compounds (IMCs) at the solder interface. In this paper, fracture mechanics study of the IMC layer for SnPb and Pb-free solder joints was carried out using finite element numerical computer modelling method. It is assumed that only one crack is present in the IMC layer. Linear Elastic Fracture Mechanics (LEFM) approach is used for parametric study of the Stress Intensity Factors (SIF, KI and KII), at the predefined crack in the IMC layer of solder butt joint tensile sample. Contrary to intuition, it is revealed that a thicker IMC layer in fact increases the reliability of solder joint for a cracked IMC. Value of KI and KII are found to decrease with the location of the crack further away from the solder interfaces while other parameters are constant. Solder thickness and strain rate were also found to have a significant influence on the SIF values. It has been found that soft solder matrix generates non-uniform plastic deformation across the solder-IMC interface near the crack tip that is responsible to obtain higher KI and KII.

The use of acoustic emission monitoring to rank paper materials with respect to their fracture toughness

In this study, a simplified Acoustic Emission (AE) equipment, in essence an AE signal conditioner and a USB (Universal Serial Bus) data acquisition system, is used to study what happens in paper structures during mechanical loading. By the use of such equipment, some parameters that can be extracted are e.g. the stress and strain at onset of AE, the stress and strain at the onset of rapid AE defined as some numerical factor (larger then one) times the initial emission rate, the emission rate at the first stage of loading and the stress and strain at final failure i.e. when the specimen loses its load carrying ability.In this study however, the interest is focused on one particular parameter i.e. the elastic strain energy density W c at onset of AE. This is a parameter with a clear physical meaning and in this study, the correlation between this parameter and a fracture toughness measure, is investigated.The conclusion is that when nine different paper materials (with a large span regarding properties) are considered, there is a correlation (however not linear) between these two parameters.