川西南部周公山地区峨眉山玄武岩有利储层分析

川西雅安地区周公山构造周公2井玄武岩取心较长、较完整,并且其紧邻高产气井——周公1井,是研究玄武岩气藏的典型井。以岩石学特征为基础,宏观和微观相结合,从岩心、电性、物性、微观特征入手将周公2井取心段峨眉山玄武岩中储层段岩石学特征、孔隙类型、流体特征及其纵向上的分布发育特征进行归纳总结并与1井产层段进行了对比研究。分析认为,川西南部地区玄武岩有利储层分布于2处,一处为顶部普遍发育的数米厚风化壳,另一处是旋回中上部的富含杏仁体角砾化玄武岩。第二类储层中发育沥青并伴随发育石英,溶孔、溶洞、裂缝普遍,但渗透率较小;其有效储集空间大多数由次生作用产生,喷溢间歇期的构造作用、风化及溶蚀作用良好的匹配关系至关重要;后期形成的构造裂缝与垂直于层面的节理缝较易形成开放体系,极可能就是破坏周公2井气藏保存条件的主要因素。     

云南绿春牛尼老白铅锌多金属矿区土壤次生晕及找矿远景分析

绿春县牛尼老白工作区位于兰坪―思茅凹陷带南段东缘之绿春褶皱带内,地球化学背景As、Hg、Pb、Zn、Sb、Bi、Au、Cu等元素在该区地层中具有明显的富集趋势。本文通过对该区2144个化探样品进行多元统计分析,认为多元素异常主要沿NW、NE向断裂展布,有规模的Zn、Pb异常主要沿F1断裂带分布,Au异常沿F2断裂带分布;且指出了1个铅锌矿、3个金矿、1个铜矿的最有利找矿远景区。     

地电化学集成技术在江苏仑山金矿找矿预测的应用

为寻找仑山金矿深部矿藏,开展了地电化学集成技术和土壤次生晕的对比试验研究。结果显示,地电化学集成技术反映已知矿体上方异常很显著,而土壤次生晕方法在此无异常显示。说明地电化学集成技术在仑山金矿区寻找隐伏金矿的富集部位是有效的。运用此技术发现具有找矿前景的异常靶区共5处,为该区的深部找矿预测指明了方向。     

Review of constitutive models for describing the time dependent behaviour of soft clays

Different classes of constitutive models have been proposed to capture the time-dependent behaviour of soft soil (creep, stress relaxation, rate dependency). This paper critically reviews many of the models developed based on understanding of the time dependent stress-strain-stress rate-strain rate behaviour of soils and viscoplasticity in terms of their strengths and weaknesses. Some discussion is also made on the numerical implementation aspects of these models. Typical findings from numerical analyses of geotechnical structures constructed on soft soils are also discussed. The general elastic viscoplastic (EVP) models can roughly be divided into two categories: models based on the concept of overstress and models based on non-stationary flow surface theory. Although general in structure, both categories have their own strengths and shortcomings. This review indicates that EVP analysis is yet to be vastly used by the geotechnical engineers, apparently due to the mathematical complication involved in the formulation of the constitutive models, unconvincing benefit in terms of the accuracy of performance prediction, requirement of additional soil parameter(s), difficulties in determining them, and the necessity of excessive computing resources and time.     

中国粮食生产效率空间溢出网络及提升路径

现有研究普遍关注粮食生产单元自身资源禀赋以及功能属性,对于经济主体相互作用所产生的外部性研究十分有限。为此,本文在空间引力模型的基础上着重分析网络外部性对粮食生产效率的影响,并以此为逻辑起点进一步探讨网络提升路径以及各空间单元在整体网络中的综合定位与潜力。结果表明,中国粮食生产网络空间溢出效应显著,对粮食生产效率具有明显的促进作用,其实质是规模经营思想在空间维度的扩展,符合近带动远辐射规律,且交通基础设施的互通互联与人口流动是实现网络空间外溢的主要路径。同时,整体网络中共存在4种潜在节点,包括核心控制型、局域核心型、潜力型以及边缘型。未来应充分发挥核心控制型节点的辐射带动作用,加强东西轴带的空间交互影响,实现农业资源技术的跨地域流动与互补。     

塔中地区东河砂岩的成岩作用和孔隙演化

塔中地区下石炭统巴楚组东河砂岩储层主要为一套滨海沉积成因的石英砂岩，其平均成分组成石英８３％，长石８％，岩屑９％、以两口井为例，应用阴极发光、扫描电镜、Ｘ射线衍射和图象分析等测试手段，研究了区内东河砂岩的成岩作用，认为影响砂岩储集性能的主要成岩作用是压实、胶结和溶解作用。方解石的胶结和溶解决定了储层具有良好的孔隙性，溶解形成的次生孔隙是砂岩的主要储集空间。恢复的东河砂岩的原始孔隙度为３８％，经历３个阶段孔隙演化后的岩芯薄片计点孔隙度平均为１４％，岩芯物性分析孔隙度平均为１７％。     

THE HILL PROBLEM WITH OBLATE SECONDARY: NUMERICAL EXPLORATION

We introduce a three-dimensional version of Hill’s problem with oblate secondary, determine its equilibrium points and their stability and explore numerically its network of families of simple periodic orbits in the plane, paying special attention to the evolution of this network for increasing oblateness of the secondary. We obtain some interesting results that differentiate this from the classical problem. Among these is the eventual disappearance of the basic family g′ of the classical Hill problem and the existence of out-of-plane equilibrium points and a family of simple-periodic plane orbits non-symmetric with respect to the x-axis.     

Alkaline diagenesis and its influence on a reservoir in the Biyang depression

Alkaline diagnesis is a diagenetic process that a reservoir undergoes under an alkaline environment. Because of the influence of alkaline formation water, the most typical characteristics of diagnesis is that quartz is obviously dissolved, feldspar is massively enlarged, and less late carbonate cement is formed in the evolution of carbonate minerals. With the decrease of the alkalinity of the formation water in diagenesis, the quartz overgrowths become common. The change in the chemical characteristics of the formation water leads to a more complex distribution of reservoir porosity at different depths than that of the secondary porosity formed by classical acidic water. It also makes the B stage of early diagenesis the important development period of secondary porosity.     

Pleistocene geochronologies for fluvial sedimentary sequences: an archaeologist's perspective

Current models of Pleistocene fluvial system development and dynamics are assessed from the perspective of European Lower and Middle Palaeolithic stone tool assemblages recovered from fluvial secondary contexts. Fluvial activity is reviewed both in terms of Milankovitch‐scale processes across the glacial/interglacial cycles of the Middle and Late Pleistocene, and in response to sub‐Milankovitch scale, high‐frequency, low‐magnitude climatic oscillations. The chronological magnitude of individual phases of fluvial activity is explored in terms of radiocarbon‐dated sequences from the Late Glacial and early Holocene periods. It is apparent that fluvial activity is associated with periods of climatic transition, both high and low magnitude, although system response is far more universal in the case of the high magnitude glacial/interglacial transitions. Current geochronological tools do not permit the development of high‐resolution sequences for Middle Pleistocene sediments, while localised erosion and variable system responses do not facilitate direct comparison with the ice core records. However, Late Glacial and early Holocene sequences indicate that individual fluvial activity phases are relatively brief in duration (e.g. 10² and 10³ yr). From an archaeological perspective, secondary context assemblages can only be interpreted in terms of a floating geochronology, although the data also permit a reinvestigation of the problems of artefact reworking. Copyright © 2005 John Wiley & Sons, Ltd.     

2013年湖北省两次降雪过程对比分析

利用常规观测资料、NCEP再分析资料、微波辐射计及多普勒雷达等资料对2013年2月7—8日干雪过程、2月18—19日湿雪过程,从水汽、不稳定、动力及温湿层结方面进行对比分析,得出如下结论：（1）2月7—8日的干雪过程水汽层次浅薄,水汽输送支仅为700 hPa弱西南气流;2月18—19日的湿雪过程水汽充沛,水汽输送支为700 hPa强西南急流和850 hPa 东南气流。（2）干雪过程低层冷平流强,层结稳定。湿雪过程低层暖平流强,冷暖交汇使大气不稳定度增加。（3）干雪过程中弱暖湿气流沿深厚冷空气垫爬升,动力辐合位于中高层,次级环流的形成减弱上升运动。湿雪过程中弱冷空气楔入到强暖湿气流底部,迫使其抬升,形成深厚上升运动区,次级环流的形成增强上升运动。（4）干雪过程整层温度<0℃,700 hPa出现冷性逆温层,-10℃层位于925 hPa附近,水汽密度、液态水含量、整层水汽含量较小;湿雪过程700 hPa出现暖性逆温层,-10℃层位于500 hPa附近,水汽密度、液态水含量、整层水汽含量较大。在上述研究的基础上给出了干、湿雪形成的三维物理模型,该模型从温湿（风）垂直层结上面体现出了干、湿雪形成的主要环境背景差异,对于干、湿雪预报具有一定的参考价值。