高频基准面旋回控制下浅水三角洲及其砂体发育模式:以松辽盆地扶余油田白垩系泉头组为例^*          下载免费PDF全文

赖洪飞  秦智  王洪君  郑锡  林艳波  鲍志东  李美俊  张云龙  张莉  吴煜潇  宋健  何陵沅 《古地理学报》2017,19(4):609-622

浅水三角洲储集层在陆相湖盆油气勘探中具有重要的意义,但基于密井网资料的精细研究仍十分缺乏。以高分辨率层序地层学和沉积学理论为指导,以松辽盆地扶余油田DT91区块白垩系泉头组四段第Ⅲ砂组14余口取心井的岩心资料和700余口密井网测井资料为对象,分析了高频基准面旋回下浅水三角洲及其砂体的发育规律。研究结果表明: (1)浅水三角洲储集层主要发育在河道、漫溢砂、分流砂坝、天然堤、决口扇和席状砂等6种成因砂体,以河道砂体和分流砂坝砂体为主。(2)在岩心和测井曲线上可识别出河道底部冲刷面、进积—退积作用面、退积—进积作用面和湖泛面等4种基准面旋回物理界面;并识别出3大类、7亚类超短期基准面旋回类型。(3)高频基准面旋回演化过程中,湖泊浅水三角洲沉积区可容空间变化不大,沉积物供给通量在可容空间增长速率(accommodation increasing rate,A)和沉积物供给通量(sediment supply rate,S)的比值A/S变化中起着主导作用,进而控制着成因砂体的数量和空间接触关系。当A/S值由小变大时,浅水三角洲的规模快速变小,成因砂体的数量也相应减少;同时,成因砂体垂向接触方式由下切叠加式→加积叠加式→孤立式变化,砂体平面分布的复合连片程度也发生由高到低的变化。  相似文献   

http://dx.doi.org/10.1016/j.gsf.2016.11.001     

Fei Gao  Lily Wang  Yongqiang Yang  Mudan Yin 《地学前缘(英文版)》2017,8(2):409-410

正The 2016 Geoscience Frontiers Annual Convention was held in Beijing,China on October 14,2015 hosted by China University of Geosciences,Beijing(Fig.1).This convention assembled earth scientists from six countries,including Australia(Dr.Christopher Spencer),Italy(Prof.Emilio Saccani),India(Prof.G.Parthasarathy and Prof.M.Jayananda),Japan(Prof.Masaki Yoshida),UK(Dr.Nick Roberts),China,and also representative from Elsevier(Beijing).  相似文献   

Characteristics of seismic disasters and aseismic measures of tunnels in Wenchuan earthquake     

Jinxing Lai  Siyue He  Junling Qiu  Jianxun Chen  Lixin Wang  Ke Wang  Junbao Wang 《Environmental Earth Sciences》2017,76(2):94

Over the past few years, accompanied by big and frequent earthquakes, more attention was paid to the tunnel earthquake resistance. To reduce tunnel seismic damage and explore the reasonable aseismic measures, the tunnel earthquake disaster investigation was employed to analyze and summarize the tunnel seismic damage on the basis of Wenchuan earthquake. Fifty-two tunnels near the epicenter of Sichuan Province were investigated: Only 7 tunnels did not show structure damage, 6 tunnels suffered the most serious damage, and the rest appeared damage to various extents. It indicates that most serious seismic damage happens to fault fracture zone, followed by entrance and common section of the tunnel. Additionally, the results display that the typical seismic damage of tunnels is lining cracking, collapsing, dislocation, construction joints cracking, and uplifting of invert, and usually lining cracking and collapsing account for a larger proportion. Therefore, the tunnel aseismic design should emphasize the fault fracture zone and tunnel entrance. Tunnel design should adopt the composite lining structure with shock absorber and whole chain alternative grouting to prevent the lining cracking and collapsing in the seismic fortification zone.  相似文献   

Experimental investigation of fine sediment deposition using particle image velocimetry     

Masoumeh MoayeriKashani  Lai Sai Hin  S. Ibrahim 《Environmental Earth Sciences》2017,76(19):655

In order to create natural and healthy water ecosystems, the impact of hydrological processes in ponds must be identified. Pond structure may affect water quality in many ways. The present study provides a novel insight into some of the hydrological processes as well as how to employ retentions to enhance storm water detention and manage discharge. In this research, particle image velocimetry is utilized to study the two-dimensional collecting efficiency of fine sediments by retention structures with a range of hydraulic features. To examine the hydrodynamic behavior of water mixed with fine particles, a sediment basin was designed. Fluorescent polymer particles (1–50 μm) were subsequently added to this fluid mix. This study demonstrates that gravitational force increases fine particle settlement by over 50% at greater depths. The optimum collecting efficiency of sediments at the water surface was found to be around 80%. It was also determined that flow rate and particle size are directly correlated and that inlets and outlets at higher levels impede fine particle dispersion in the water column. For these reasons, it seems that adjusting the hydraulic parameters may diminish siltation.  相似文献   

Discrete element simulation of mine tailings stabilized with biopolymer     

Rui Chen  Xiaobin Ding  Lianyang Zhang  Yongli Xie  Hongpeng Lai 《Environmental Earth Sciences》2017,76(22):772

This paper presents a series of numerical simulations using discrete element method (DEM) to study the behavior of biopolymer-stabilized mine tailings (MT). Validation is conducted by comparing the DEM results with the experimental data. The macro-behavior comparison shows that the DEM simulations are in good agreement with experimental results. Analysis of the micro-parameters indicates more biopolymer induces larger tensile and shear strengths, confirming the experimental results which show that the strength of MT increases with higher biopolymer concentration. Analysis of the bond breakage pattern suggests that at the same strain level MT stabilized with higher biopolymer concentration show less bond breakage percentage. MT specimen under greater confining pressure develops larger shear band than that under lower confining pressure. Higher biopolymer concentration induces the increase in larger inter-particle bonding strength and thus larger cracking resistance and greater macro-strength.  相似文献   

花岗岩演化与铀钍元素富集的关系:以粤北贵东岩体为例   总被引：3，自引：0，他引：3       下载免费PDF全文

娄峰  李宏卫  陈光明  敖文波  赖中信  卢映新  杨燕娜 《地学前缘》2011,18(1):110-117

对粤北贵东岩体铀钍丰度变化特征的研究表明,原地重熔过程导致铀钍元素向花岗岩体的上方汇聚富集,并造成铀、钍元素在空间上的分离,即在花岗岩体中,铀的丰度带位处钍丰度带之上。陆壳多次原地熔融(重熔)不但导致复式花岗岩体形成,同时造成铀元素在晚期岩体中的富集。贵东岩体内燕山早期岩体铀钍含量的东西差异被认为与卷入熔融的铀源层(寒武-震旦系)的初始埋深有关,而复式岩体铀含量的南北差异,则被解释为与晚期重熔界面倾斜方向所导致的晚期岩体的剥蚀深度有关。高铀含量和高铀钍比值并存往往是晚期岩体埋深较浅的表现,对于深部隐伏矿床的寻找有重要指示作用。  相似文献   

Present-day crustal movement and tectonic deformation in China continent   总被引：9，自引：3，他引：6  

王琪  张培震  牛之俊  J.T.Freymueller  赖锡安  李延新  朱文耀  刘经南  R.Bilham  K.M.Larson 《中国科学D辑(英文版)》2002,45(10):865-874

Velocity field of China continent constrained by Global Positioning System (GPS) reveals both continuous and block-like styles of deformation. Continuous deformation commonly characterizes actively deforming mountain ranges such as the Tianshan Mountain, Qilian Mountain, and Tibet. The block-like movement often represents deformation in the tectonically stable regions such as Ordos, South China and Tarim blocks. GPS measurements indicate 5.1±2.5 mm/a left-lateral strike-slip rate along the Altun fault. Eastward convergence along the Longmenshan fault is less than 6.7 ± 3.0 mm/a. South China moves 11–14 mm/a eastward compared with the stable Eurasia. These low slip rates do not imply rapid eastward extrusion of China continent predicted by the model of “continental extrusion”. It appears that “crustal thickening” model more properly describes both continuous and block-like styles of deformation in China continent.  相似文献   

Environmental degradation in the Hexi Corridor region of China over the last 50 years and comprehensive mitigation and rehabilitation strategies   总被引：3，自引：0，他引：3  

G.?WangEmail author  Y.?Ding  Y.?Shen  Y.?Lai 《Environmental Geology》2003,44(1):68-77

The regional hydrology and ecosystems of the Hexi Corridor region of northwestern China have changed over the last half century under the driving force of intense human activity and regional climate changes. Streamflow issuing from mountains in the eastern section of the Corridor by way of the Shiyang River has decreased significantly. Annual mountain outflow from the Heihe and Shule Rivers in the central and western portions of the Corridor, respectively, have tended to increase; however, their downstream discharge has decreased sharply. These lower reaches clearly display anthropogenic hydrological features. Water salinization and pollution have worsened. Presently, up to 208 km of river courses exhibit the poorest water pollution grades of IV and V. Overall, the forested area in the south Qilian Mountain region has decreased by 16.5% in the last 50 years, but has recently begun to show a gradual increase. However, natural desert forests in the northern portion of the Hexi Corridor have continued in a trend of degradation and rapid disappearance, with 3431 km² lost in Minqin and Ejin counties alone. Grasslands have been progressively degraded and their area decreased such that grasslands in the Hexi Corridor region only cover 46.86% of their former area. Desertification has been exacerbated and the grasslands' stock capacity reduced. In the Hexi Corridor region desertification has proceeded swiftly over the last 50 years, reaching, in the early 1980s, a maximum annual rate of 2.15% of total initial grassland area. However, from the late 1980s through the 1990s their desertification rate has dropped significantly. A unified watershed-scale plan for water use and management in different regions of the Hexi Corridor, considering water demands for economic development as well as ecosystem maintenance and remediation, must be implemented. The improved and ultimate sustainability of regional development for the Hexi Corridor is linked to following ecological criteria in exploiting land resources, and to systematically protect ecosystem function, allowing for sound ecosystem development.  相似文献   

垂直基准定义及联接     

徐菊生  王建华  赖锡安  卓力格图  张瑞刚  莫志明 《大地测量与地球动力学》2001,21(1):24-34

介绍了利用地球位模型、地面重力资料、GPS和水准测量结果确定定全球高程基准及局部性垂直基准联接的基本原理和方法 ,给出了计算公式 ,并列出了国际上有关研究所获得的主要成果 ,最后对我国所需要进行的相关研究工作提出了建议  相似文献   

Effects of altitude on critical ionization velocity experiments in space     

Shu T. Lai  Edmond Murad  William J. McNeil 《Planetary and Space Science》1991,39(12):1707-1713

The efficiency with which critical ionization velocity (CIV) discharges can be generated in space experiments is affected by the altitude at which the experiments are conducted. At around 500 km higher plasma density enhances plasma lower hybrid instability, momentum coupling efficiency, and charge exchange which is needed for seed ionization. At higher altitudes where atomic hydrogen and helium become the dominant ambient neutral species, the conditions for CIV discharge may improve considerably because less energy is lost to atmospheric ionization, even though the ambient density is reduced.  相似文献