冻土区天然气水合物勘探低温钻井液理论与试验

天然气水合物是在特定的低温与高压条件下形成的产物。在天然气水合物勘探工作中,低温钻井液是获得天然气水合物真实样品的重要保证条件之一。低温钻井液应具有低的冰点、良好的抵制能力与良好的流动性。结合天然气水合物勘探工作的特点,在试验的基础上,对比分析了PAM、PHPA、PAC-141、Na-CMC与KHm的分子结构、官能团的种类与数量对钻井液的防塌能力和流动性的影响,得出了几种处理剂的耐低温能力大小的顺序为：PAC-141〈PHPA〈PAM〈Na-CMC〈KHm,为天然气水合物勘探中低温钻井液的配制与使用,奠定了重要的基础。     

泥岩有水热解产生低分子量有机酸实验研究

直接采用泥岩岩屑进行有水热解,测定实验后水溶液中几种常见低分子量有机酸.结果表明,在实验的水溶液中检测到了丰富的低分子量有机酸,组成上主要为一元羧酸,其中又以乙酸占优势.讨论了不同热解条件对有机酸产率以及组成的影响.实验结果表明,有机酸总量随加热温度和时间增加而增加,并且溶液中不同有机酸相对组成也发生变化.当温度高于1...     

Geochemical Mapping: With Special Emphasis on Analytical Requirements

More than 40 national and regional geochemical mapping projects in the world carried out from 1973 to 1988 do not conform to common standards. In particular they have many analytical deficiencies. In the period 1988 to 1992, the International Geochemical Mapping project （Project 259 of UNESCO＇s IGCP Program） prepared recommendations designed to standardize geochemical mapping methods. The analytical requirements are an essential component of the overall recommendations. They included the following： 71 elements should be analyzed in future mapping projects; the detection limits of trace and ultratrace elements must be lower than the corresponding crustal abundances; and the Chinese GSD and Canadian STSD standard sample series should be used for the correlation of global data. A proposal was also made to collect 5000 composite samples, at very low sampling densities to cover the whole Earth＇s land surface. In 1997 an IUGS Working Group on Global Geochemical Baselines was formed to continue the work which began with IGCP 259. From 1997 up to now, new progress has been made especially in China and FOREGS countries under the aegis of this working group, including the study of suitable sampling media, development of a multi-element analytical system, new proficiency test for selection of competent laboratories and role of wide-spaced mapping in mineral exploration. One of the major problems awaiting solution has been the inability of many laboratories to meet the IGCP recommendations to generate high quality geochemical maps. Fortunately several laboratories in China and Europe have demonstrated an ability to meet the requirements and they will be well placed to render technical assistance to other countries.     

斜坡非饱和带低渗透岩石结构体风化前锋扩展过程

非饱和带低渗透岩石结构体风化前锋扩展是斜坡灾害孕育过程中的关键环节之一。到目前为止,化学风化领域的研究成果主要集中在高水-岩比的饱和环境下单矿物及矿物成分单一的碳酸盐岩的风化动力学方面,非饱和环境下的岩石风化研究还主要限于风化产物的特性描述方面。斜坡非饱和带低渗透岩石结构体风化前锋扩展是一种高度复杂的THMC过程。由于在溶解对象、溶解液及溶解过程的水动力-水化学环境等方面存在的显著差异,既有的地质材料风化动力学成果为探索这一复杂过程提供了理论储备,但还不能阐明其核心机理。斜坡非饱和带低渗透岩石结构体风化前锋的扩展过程研究不仅可以加深人们对斜坡灾害孕育的理解,为灾害预报-预警及其控制提供理论依据,同时可以促进岩石-岩体力学及浅表生水文地球化学等相关学科的交叉与发展。     

邹平火山岩盆地铜矿地质成因地球物理特征探讨

邹平铜矿处于齐河-广饶深大断裂带南部的邹平火山岩盆地中,形成于破火山口火山通道充填的石英正长闪长岩岩颈中央上部,包括伟晶岩型铜矿和细脉浸染状斑铜矿床两种类型。前者矿体较小,但品位高;后者品位较低,但规模中等。含矿石英正长闪长岩等密度小、磁性弱,故在火山岩系中呈现高背景重力场上的重力低和杂乱高磁场背景中的低负异常,即“重磁同低”,且高极化。重磁同低异常区和高极化率异常带,是本区寻找铜矿的有利部位。     

S-wave velocity images of the Dead Sea Basin provided by ambient seismic noise

Based on passive seismic interferometry applied to ambient seismic noise recordings between station pairs belonging to a small-scale array, we have obtained shear wave velocity images of the uppermost materials that make up the Dead Sea Basin. We extracted empirical Green’s functions from cross-correlations of long-term recordings of continuous data, and measured inter-station Rayleigh wave group velocities from the daily correlation functions for positive and negative correlation time lags in the 0.1–0.5 Hz bandwidth. A tomographic inversion of the travel times estimated for each frequency is performed, allowing the laterally varying 3-D surface wave velocity structure below the array to be retrieved. Subsequently, the velocity-frequency curves are inverted to obtain S-wave velocity images of the study area as horizontal depth sections and longitude- and latitude-depth sections. The results, which are consistent with other previous ones, provide clear images of the local seismic velocity structure of the basin. Low shear velocities are dominant at shallow depths above 3.5 km, but even so a spit of land with a depth that does not exceed 4 km is identified as a salt diapir separating the low velocities associated with sedimentary infill on both sides of the Lisan Peninsula. The lack of low speeds at the sampling depth of 11.5 km implies that there are no sediments and therefore that the basement is near 10–11 km depth, but gradually decreasing from south to north. The results also highlight the bowl-shaped basin with poorly consolidated sedimentary materials accumulated in the central part of the basin. The structure of the western margin of the basin evidences a certain asymmetry both whether it is compared to the eastern margin and it is observed in north–south direction. Infill materials down to ∼8 km depth are observed in the hollow of the basin, unlike what happens in the north and south where they are spread beyond the western Dead Sea shore.     

重力、航磁资料在花岗岩型铀矿成矿研究中的应用

本文利用重磁场资料对我国南方一些花岗岩体的侵位状态和岩浆动力场进行了分析，并按动力场的强弱对岩体进行了分类。根据重力资料对苗儿山-越城岭、诸广山和贵东花岗岩体的反演计算，讨论了这些岩体的深部分布形态，提出了岩浆流动的3种方式，指出了富大铀矿床、大型铀矿聚集区的赋存部位及其与航磁异常的密切联系。     

渤南油田中部古近系沙河街组低渗透储层岩石学和成岩作用

该区储层岩石类型主要为岩屑质长石砂岩,溶解作用是主要的建设性成岩作用,压实、自生矿物充填和胶结作用是主要的破坏性成岩作用,成岩阶段处于晚成岩A亚期。该区储层较高的孔隙度是晚成岩期强烈的溶解作用形成次生溶孔的结果,而储层砂岩较低渗透率的主要成因机理是成岩期各种自生矿物的充填和胶结作用;此外,溶蚀作用形成的孤立、互不连通的粒间孔也是形成低渗微细喉道储层的主要原因。有利孔隙组合为粒间溶蚀孔-原生粒间孔-粒内破碎缝,有利储层的分布受砂体分布、构造配置及成岩作用的联合控制。     

辽西晚古生代长茂河子辉绿岩墙群的地球化学特征

根据全岩K-Ar年龄(287.5~243.6Ma), 辽西朝阳长茂河子辉绿岩墙群形成于晚古生代.这些辉绿岩分为低铁钛辉绿岩和高铁钛辉绿岩2种, 以低铁钛辉绿岩为主.低铁钛辉绿岩以低TiO₂(< 2%)、FeO_t(12.39%~15.33%)、V(227~335μg/g)、Sc(24~36μg/g) 含量和高的SiO₂ (45.61%~47.72%)、Al₂O₃(12.51%~16.71%)、MgO(6.66%~9.31%)、K₂O(0.57%~2.39%)、Cr(107~177μg/g)和Ni(96~235μg/g) 含量, 以及低Ti/Y(327~496)和Ti/Zr (69~114) 比值为特征, 类似于大陆拉斑玄武质岩石; 高铁钛辉绿岩以高的TiO₂ (5%~6%)、FeO_t(22.13%~22.16%)、V(850~859μg/g)、Sc(51~52μg/g) 含量和低的SiO₂ (42.88%~44.90%)、Al₂O₃(11.53%~11.57%)、MgO (5.15%~5.29%, Mg#=0.32)、K₂O (0.48%~0.51%)、Cr(< 2μg/g)和Ni(< 30μg/g) 含量及高的Ti/Y(1046~1106)、Ti/Zr(250~263) 比值为特征, 类似于Skaergaard侵入体.这些辉绿岩相对富集Rb、Th、U、Pb、Ti和轻稀土元素, 而相对亏损Ba、Sr、P和Nb、Ta.ε_Nd(t) (-6.43~-4.12)、ε_Sr(t) (42.94~64.19) 显示Sr-Nd同位素组成较为均匀, 并反映它们源于富集岩石圈地幔.认为长茂河子辉绿岩形成于富集岩石圈地幔的部分熔融, 经历了岩浆结晶分异与地壳混染作用.高铁钛辉绿岩和低高铁钛辉绿岩形成环境不同, 前者形成于相对低氧逸度或相对封闭的结晶环境中.      

塔里木盆地阿克库勒地区石炭系卡拉沙依组成岩作用

阿克库勒地区卡拉沙依组碎屑岩储层的成分成熟度和结构成熟度均较低．储层的次生溶蚀孔隙所占比例远高了：原生孔隙，次生孔隙是储层的主要储集空间．样品数据统计显示，卡拉沙依组储层属于低孔、低渗储层类型．根据岩石薄片、铸体薄片观察及储层样品的扫描电镜和阴极发光分析结果，本区石炭系储层主要经历的成岩作用有压实（压溶）作用、胶结作用、溶蚀作用和交代作用，其中碳酸盐矿物的沉淀和溶蚀作用是本区卡拉沙依组储层所经历的最重要的成岩作用．成岩作用已达到晚成岩B期，早期方解石交代石英颗粒并发生大量溶蚀，生成大量次生孔隙，晚期方解石没有发生溶蚀．