断层输导作用与油气充注作用关系分析   总被引：2，自引：0，他引：2       下载免费PDF全文

刘震  张旺  曹尚  刘明洁  张威  董冬 《地质科学》2014,49(4):1302-1313

断层是控制油气藏形成的重要因素之一;断层的开启及闭合影响到油气运移与聚集的效率。但油气在断层中的运移与在砂层中的充注存在差异性这一问题长期被忽视。一般认为;只要发育断层;其断开的渗透层就会被油气充注;极少关注地层水和石油的压缩特性对充注的影响。本文提出;地下单断层活动时;深部油气在超压作用下以涌流方式难以快速充注进入中浅层被切割的砂体;因此;单砂体至少要存在一条断层作为泄水出口;石油才能通过其余断层充注进入砂体;即单砂体要发育两条及两条以上断层;石油才能注入砂体。在断层静止期;油气通过渗流方式沿特定深度范围断面垂向运移;对油气垂向运移距离影响较小。本文运用4个大型盆地的典型油气藏与断层分布关系讨论了本文观点。该观点对油气成藏规律研究及成藏目标评价有较重要参考意义。  相似文献   

巴丹吉林沙漠南缘的植物固沙问题     

赵文智  白雪莲  刘婵 《中国沙漠》2022,42(1):5-11

在野外考察的基础上,选择13个典型样地,研究了巴丹吉林沙漠南缘植被组成、群落特征和植被格局。结果表明：调查的样地中有荒漠植物31种,其中灌木12种,多年生草本11种,一二年生草本8种。种群密度3 000—14 000株·hm^-2,优势种在群落中地位显著,群落稳定性较差;植被斑块面积小、最大斑块指数低。沙漠南缘年降水量虽然仅100 mm左右,但有霸王（Zygophyllum xanthoxylon）、红砂（Reaumuria soongarica）和沙蒿（Artemisia desertorum）等灌木和半灌木天然植物群落分布,有白刺（Nitraria tangutorum）和膜果麻黄（Ephedra przewalskii）灌丛沙堆,沙丘上生长着沙拐枣（Calligonum mongolicum）、沙鞭（Psammochloa villosa）等种群生存,且在沙漠延伸带流动沙丘上已成功建立了梭梭（Haloxylon ammodendron）人工固沙植被,表明在巴丹吉林沙漠南缘建立以乡土植物为主的固沙植被是可行的。在未来研究中,应在山水林田湖草沙生命共同体理念下加强从区域尺度上解析水、植被和沙的关系,系统了解生态系统的原真性、完整性和连通性及生态系统稳定性维持等问题,优化生态景观格局,确定生态保护目标和建设规模,同时要加强对乡土植物适应干旱风沙机制和扩繁保育技术研究,以便为区域生态建设和生态保护提供科技支撑。  相似文献   

PLAM指数跟踪方法对中国沙尘天气过程及其波动变化特征的研究          下载免费PDF全文

王继志  杨元琴  王亚强  张光智 《气象与环境学报》2013,29(5):92-97

采用1980-2011年气象台站地面气象要素观测资料、高空探空资料,时间和空间加密气象观测站资料,以及中国气象档案馆原始天气图表等资料,基于沙尘气溶胶浓度（PM₁₀）潜势源地贡献函数PSCF（Potential source contribution function）的沙尘系统追踪方法,发展空气质量气象条件PLAM（……）指数对沙尘天气过程的路径跟踪,给出1980-2011年东北亚沙尘天气过程特征分布;采用Spline趋势分析,讨论沙尘天气系统强度的年变化特征。结果表明：基于气溶胶浓度PSCF函数和气象条件PLAM指数追踪得出,中国和东亚地区沙尘天气过程年际强度变化并非单调减弱,具有历史持续性与转折突变性并存的波状变化趋势,出现准10 a的高低频活动特征。  相似文献   

Structural Control of Sand Bodies and Deep Exploration for Oil and Gas     

Cheng Rihui  Lin Changsong  ZHENG Herong 《世界地质(英文版)》2002,5(2)

The structural styles can be used to analyses and predict developments and distributions of sand bodies in a rift basin. The dynamic process of faulting and sedimentation can be expressed as follow: the basin topography controlled by fault activity can control water dynamics; which in turn affect the transport and sedimentation of sediments. The corresponding analysis between structural styles and sand depositional types includes the following aspects: (1) in section, the corresponding between development of fault terraces and sand depositional types; (2) in plane, the relationship between faults' association and distributions of sand bodies. There are four types of terrace styles to be identified. They are Steep Slope Single Fault Terrace (SSSFT), Steep Slope Multiple Fault Terrace (SSMFT), Gentle Slope (GS) and Gentle Slope Multiple Fault Terrace (GSMFT), which also can be divided into six subtypes by the timing of the faults activities and the directions of their activity migrations (basinward and landward or marginward). They correspond to the following sand depositions such as alluvial fan, fan delta and turbidite fan etc.. The analysis of structure-sedimentation is a discussion on the rank Ⅲ sequence evolution under the condition of pulsing or episodic fault activities. It has been recognized four plane fault associations such as the comb, the broom, the fork and the fault-fold association as well as the corresponding sand distributions. Structural-sedimentary models above mentioned are significant for the deep oil and gas exploration when lacking of the drill data. It may reduce multiple resolutions in the interpretation of seismic-sedimentary facies and promote sand predictions through the constraints of the structural styles of the basin units. The structural-sedimentary pattern can be used as a geological model in oil and gas exploration in the rift basins.  相似文献   

黄河海港动力地貌条件的初步探讨   总被引：5，自引：0，他引：5  

耿秀山  吴世迎 《地理学报》1988,(4)

在黄河海港选址及未来预测中,作者通过海岸动力、悬沙分布、粒度特征、地形对比研究法等分析,获得了黄河口迁离黄河海港附近8年后的海底蚀淤厚度、侵蚀与淤积速率、净余侵蚀总重量、泥沙活动带的活动规律与海岸剖面塑造及其演变的关系,从而为黄河海港的设置与工程布局提供了科学依据。  相似文献   

风沙流中沙粒浓度分布的实验研究   总被引：9，自引：0，他引：9  

王洪涛  董治宝  张晓航 《地球科学进展》2004,19(5):732-735

利用粒子图像测速技术（PIV）,在风洞内对与天然沙接近的石英沙风沙流沙颗粒浓度沿高度分布进行了研究。对 3种不同轴线风速研究结果表明,风沙流中沙粒浓度沿水平方向基本不变,而随高度呈指数衰减,而且其衰减速率与风速密切相关。风速越大,衰减速率越慢;风速越小,衰减速率越快。风沙运动一旦发生时,靠近沙床表面的沙粒浓度随风速变化很小,可以认为趋于稳定,达到最大值。  相似文献   

The aeolian sedimentation record of the Thar desert   总被引：1，自引：0，他引：1  

A. K. Singhvi  Amal Kar 《Journal of Earth System Science》2004,113(3):371-401

A review of the aeolian sedimentary record of the Thar desert is presented. This includes a regional survey of the major dune forms, their genesis and their relationship to climate and other regional landforms. A key aspect of this work is the chronometry of the dunes using luminescence methods. Luminescence dating of sand has enabled quantification of the duration of the phases of sand aggradation and quiescence, time scales of dune migration and the dating of pedogenic carbonates. We demonstrate that the conventional wisdom of synchronicity of dune aggradation with glacial epoch is not true in the context of Thar sands and here only a short durationwindow of opportunity existed for dune aggradation. Luminescence ages further suggest that this window occurred during a transitional climatic regime from glacial to interglacial about 4–10 ka after the glacial epoch. Other inferences included are that:

–	• the aeolian activity in the Thar began over > 150 ka, resolving that Thar is not of anthropogenic origin as suggested previously;
–	• the present spatial extent of the aeolian activity in the Thar is in a contracted stage compared to that in the geological past, which refutes the arguments on its rapid north-eastward expansion;
–	• the current dune migration rates in areas of significant human-induced disturbances are much higher than during the geological past;
–	• the monsoon activity in the Thar varied significantly, from being minimal during the isotopic marine stages 4 and 2 to being close to the present during stage 3;
–	• on shorter time scales the dune activities correlated with the lacustrine records of the region with a phase difference of a few centuries and a periodicity of ∼ 1500 years;
–	• the sand aggradation climate in the southern margin in Gujarat gradually shrank northwards such that in general dunes older than 10 ka are seen in the extreme southern margin and dunes younger than 2ka ages occur mostly in the western part of Rajasthan.

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陕北风沙区大保当煤矿开采的生态影响分析     

钱者东  秦卫华  李道进 《西部资源》2012,(1):84-86

陕北风沙区位于毛乌素沙地东南缘,是毛乌素沙地向黄土高原的过渡地带,自然环境十分脆弱。本文通过对陕北风沙区大保当井田进行实地调查研究,结合遥感影像,运用图形叠置法、类比分析法和生态机理法分析了在该地区进行煤矿开采对当地自然植被、野生动物以及神木臭柏自然保护区的影响,并提出相应的生态保护措施。  相似文献   

A study on the limit void ratio characteristics of medium to fine mixed graded sands     

Y. Yilmaz   《Engineering Geology》2009,104(3-4):290-294

The minimum and maximum void ratios, corresponding to states of densest and loosest packing, of 111 systematically prepared mixed graded sand samples are determined with Method 2A and Method B according to ASTM D 4253 and ASTM D 4254 standards, respectively. Although, those standards are applicable to soils that may contain up to at most 15% fines content, for the harmony of the results even for samples having fines content greater 15%, no other methods are used throughout the experimental program. The test results show that 3rd degree polynomial equations derived from existing experimental data, as a function of packing material percentage, are quite reasonable (R² ≈ 1.0) to estimate the variation of minimum and maximum void ratios for the sands considered. Furthermore, error analysis of the limit void ratios is also carried out. It is found that predictability of maximum void ratio for the soil types and gradations considered is more accurate than that of minimum void ratio.  相似文献   

Physical modelling of sand injectites     

N. Rodrigues  P.R. Cobbold  H. Lseth 《Tectonophysics》2009,474(3-4):610-632

Sand injectites are structures that result from intrusion of fluidized sand into fractures. We have studied them in the Tampen Spur area of the North Sea, and have reproduced them experimentally, by driving compressed air through layers of sand, glass microspheres, and silica powder. The silica powder was cohesive and capable of hydraulic fracturing, whereas the sand and glass microspheres were almost non-cohesive and therefore able to fluidize. The models were dynamically similar to their natural counterparts, for as long as equilibrium was static. When the processes became dynamic, so that inertial forces were significant, the scaling was approximate and the corresponding Reynolds numbers differed. The experimental apparatus was a square box, 1 m × 1 m wide, resting on a grid of fluid diffusers. During the experiments, the fluid pressure increased, until it attained and surpassed the weight of overburden. Flat-lying hydraulic fractures, containing air, formed within cohesive and least permeable layers. Heterogeneities in material properties and layer thicknesses were responsible for localizing fracture networks. When any one network broke through to the surface, rapid flow of air through the fractures fluidized the underlying mobile materials and even depleted some of the layers. Some of the fluidized material extruded at the surface through vents, forming volcanoes and sheets. The remainder lodged at depth, forming sand injectites or laccoliths. Conical sand injectites formed preferentially, where layers had high resistance to bending. Laccoliths formed nearer the surface, where overlying layers had low resistance to bending. The experimental sand injectites were broadly similar to those in the Tampen Spur area of the North Sea, as well as other areas.  相似文献