Joint elastic‐electrical effective medium models of reservoir sandstones     

Angus I. Best  Lucy M. MacGregor  Jeremy Sothcott  Tim A. Minshull 《Geophysical Prospecting》2011,59(4):777-786

Improvements in the joint inversion of seismic and marine controlled source electromagnetic data sets will require better constrained models of the joint elastic‐electrical properties of reservoir rocks. Various effective medium models were compared to a novel laboratory data set of elastic velocity and electrical resistivity (obtained on 67 reservoir sandstone samples saturated with 35 g/l brine at a differential pressure of 8 MPa) with mixed results. Hence, we developed a new three‐phase effective medium model for sandstones with pore‐filling clay minerals based on the combined self‐consistent approximation and differential effective medium model. We found that using a critical porosity of 0.5 and an aspect ratio of 1 for all three components, the proposed model gave accurate model predictions of the observed magnitudes of P‐wave velocity and electrical resistivity and of the divergent trends of clean and clay‐rich sandstones at higher porosities. Using only a few well‐constrained input parameters, the new model offers a practical way to predict in situ porosity and clay content in brine saturated sandstones from co‐located P‐wave velocity and electrical resistivity data sets.  相似文献   

Rock warming and drying under simulated intertidal conditions,part I: experimental procedures and comparisons with field data     

Martin A. Coombes 《地球表面变化过程与地形》2011,36(15):2114-2121

The wetting–drying and warming–cooling behaviours of rock and stone are known to influence the nature and rate of weathering. The way materials warm‐up and dry‐out also influences their suitability as biological substrata. While rock thermal behaviours have been measured under controlled laboratory conditions, previous experiments have largely been restricted to terrestrial simulations due to practical constraints. Where efforts have been made to simulate intertidal conditions, expansion and contraction of rocks or rates of breakdown (i.e. sediment production and weight loss) have been measured, while detailed observations of thermal and drying behaviours have rarely been made. A simple, semi‐automated procedure is described that enabled measurement of surface temperatures and desorption (evaporative water loss) for different material types (rock and concrete) under simulated semidiurnal tide conditions. Some preliminary results are presented illustrating the types of data that were obtained, and comparisons are made with temperature data collected on a rock platform in the UK to assess the ability of the procedure to adequately represent field conditions. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Bio-optical characteristics of Cariaco Basin (Caribbean Sea) waters     

Laura Lorenzoni  Chuanmin HuRamón Varela  Glenda AriasLaurencia Guzmán  Frank Muller-Karger 《Continental Shelf Research》2011,31(6):582-593

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沁水盆地南部变质变形煤储层特征层气富集区划分          下载免费PDF全文

卫明明  琚宜文  薛传东  侯泉林 《地质科学》2011,(3):905-918

沁水盆地南部周缘被挤压性断裂褶皱带所围限,区内缓坡带形成煤层气富集区.受中新生代区域构造—热演化影响,盆地内煤储层在深成变质作用基础上叠加了不同程度的构造动力变质作用和岩浆热变质作用,产生了不同程度的变质和变形,导致其在变质变形程度、含气性及渗透性等煤储层物性方面具有不同的特征,有明显的区域分异,形成展布方向与盆地复向...  相似文献   

南宁市泥岩与泥质粉砂岩互层地区某滑坡特征及防治措施     

彭庭国 《矿产与地质》2013,(5):421-423

经过勘查和地质调查,该滑坡地处由泥岩与泥质粉砂岩组成的山坡,属典型的膨胀岩边坡问题。通过分析滑坡特征,对滑坡进行稳定性计算,提出了抗滑桩＋锚杆＋网格梁的综合防治措施。  相似文献   

新疆契列克其铁矿床地质特征及找矿标志          下载免费PDF全文

晋红展 《江苏地质》2013,37(2):308-312

新疆契列克其铁矿位于阿克陶县.目前,矿区内发现2个矿体、12个铁矿矿脉,赋矿地层为奥陶—志留统下组(未分)的第一、第二岩性段.矿床成因类型为沉积变质碳酸盐型菱铁矿.通过对矿区成矿地质背景、矿体特征、找矿标志的研究、分析,阐述了矿区地质、矿床、矿石特征和矿体找矿标志,为矿区及其外围进一步找矿提供参考.  相似文献   

鄂尔多斯盆地延长组长7沉积期物源分析及母岩类型研究   总被引：2，自引：0，他引：2  

张才利  张雷  陈调胜  张艳  杨亚娟  黄静  贺静  李慧 《沉积学报》2013,31(3):430-439

通过对鄂尔多斯盆地延长组长7砂岩的类型、轻重矿物特征、重矿物聚类分析及泥岩的地化特征研究,并结合盆地周边源区露头剖面的岩性组合资料,讨论了长7沉积期的物源方向,恢复各源区母岩性质。经研究表明:鄂尔多斯盆地长7沉积期存在五个方向物源,东北、西南为主要的物源方向,西北、南部作为次要物源方向;其中东北源区母岩以中基性岩浆岩、高级变质岩为主,西南源区母岩以白云岩、浅变质岩为主,西北源区母岩以沉积岩为主,浅变质岩次之,南部源区母岩以含灰岩、碎屑岩为主,浅变质岩次之;另外经讨论证实西部存在局限的物源供给区,母岩主要为白云岩。  相似文献   

Energy dissipation in engineered sand of large damping ratio     

《Geomechanics and Geoengineering》2013,8(2):135-140

Many geotechnical problems such as seismic resistant designs and machine vibrations require the installation of dampers or isolators to control the amplitude of vibrations. Engineered fills designed with increased capability of dissipating energy can provide a more economical approach to control excessive vibrations. This study presents a novel technique to increase the damping ratio of sand without affecting its stiffness and shear strength. The increase in damping ratio is evaluated by performing resonant column tests on the engineered sand. The damping ratio of the sand is increased by adding a controlled amount of viscoelastic material to the voids. The resonant column tests indicate that the damping ratio of the sand can be increased manifold without affecting the shear modulus. The micromechanical evaluation of the results shows a good correlation between the particle surface area in contact with the pore-mixture and the damping ratio of the sand. The suitability of engineered sand as foundation material is also evaluated by performing direct shear tests. The direct shear tests on mixtures indicate similar or better shear strength parameters compared to pure sand.  相似文献   

南极菲尔德斯半岛土壤氮循环微生物类群数量与功能活性的初步研究          下载免费PDF全文

刘杰张丹丹  董龙龙王能飞 《极地研究》2017,29(1):82-89

南极乔治王岛南端的菲尔德斯半岛被认为是研究南极生态与生物资源的理想之地。本研究从该半岛全岛范围采集了3类不同类型的土壤样品,采用传统最大或然法(MPN)对其所含氮循环各类群微生物的总量进行了测定,同时利用常规Griess试剂、纳氏试剂等显色法初步估算了各菌群的功能活性强度,并结合土壤理化性质和采样点生态等进行了初步分析。目的是对该半岛土壤氮循环微生物进行先期初步了解,为进一步深入研究它们的其他特性奠定基础。结果表明:13个土样中所含氮循环微生物总量趋势为氨化菌反硝化菌硝化菌和固氮菌(活菌数),除极个别样品外均具有不同程度的硝化、反硝化、氨化活性。其中,所有土壤样品均具有比较高的氨化菌含量及氨化活性强度;丘陵山坡土壤的反硝化菌含量与反硝化活性强度要高于动、植物区土壤(极个别样品除外);动物区和植物区土壤的硝化菌含量较少,但硝化活性强度较高,预示着可能存在高效功能菌株;而丘陵山坡土壤的硝化菌含量及硝化活性强度则表现得高低不一。本结果为进一步深入研究该地区氮循环微生物提供了前期参考。  相似文献   

Characterization of the solar light field within the ocean mesopelagic zone based on radiative transfer simulations     

《Deep Sea Research Part I: Oceanographic Research Papers》2014

The solar light field within the ocean from the sea surface to the bottom of the mesopelagic zone was simulated with a radiative transfer model that accounts for the presence of inelastic radiative processes associated with Raman scattering by water molecules, fluorescence of colored dissolved organic matter (CDOM), and fluorescence of chlorophyll-a contained in phytoplankton. The simulation results provide a comprehensive characterization of the ambient light field and apparent optical properties (AOPs) across the entire visible spectral range within the depth range 200–1000 m of the entire mesopelagic zone for varying chlorophyll-a concentration and seawater optical properties in the mixed surface layer of the ocean. With increasing depth in the mesopelagic zone, the solar irradiance is reduced by ~9–10 orders of magnitude and exhibits a major spectral maximum in the blue, typically centered around a light wavelength of 475 nm. In the green and red spectral regions, the light levels are significantly lower but still important owing to local generation of photons via inelastic processes, mostly Raman scattering and to a lesser extent CDOM fluorescence. The Raman scattering produces a distinct secondary maximum in irradiance spectra centered around 565 nm. Comparisons of our results with light produced by the radioactive decay of the unstable potassium isotope contained in sea salt (⁴⁰K) indicates that the solar irradiance dominates over the ⁴⁰K-produced irradiance within the majority of the mesopelagic zone for most scenarios considered in our simulations. The angular distribution of radiance indicates the dominance of downward propagation of light in the blue and approach to uniform distribution in the red throughout the mesopelagic zone. Below the approximate depth range 400–500 m, the shape of the angular distribution is nearly invariant with increasing depth in the green and red and varies weakly in the blue. The AOPs at any light wavelength also assume nearly constant values within the deeper portion of the mesopelagic zone. These results indicate that the mesopelagic light field reaches a nearly-asymptotic regime at depths exceeding ~400–500 m.  相似文献