柴达木盆地西部地区咸化湖盆天然气地球化学特征及成因类型判识指标——以古近系—新近系为例

根据天然气地球化学基本理论,对柴达木盆地西部（柴西）地区天然气的地球化学特征进行分析。测试和收集该地区18个油气田及含油气构造的83个天然气样品,分析其组分和C同位素数据,结果显示,该区天然气以烃类气体为主,烃类含量介于79.24%~99.81%之间,天然气比重介于0.72~1.36之间,天然气干燥系数（C1/C2+）介于1.04~617.8之间,甲烷C同位素值介于-51.4‰~-24.2‰之间,乙烷C同位素值介于-34.2‰~-17.4‰之间。在此基础上,对该区不同构造带的天然气成因类型进行研究。研究结果表明,柴达木盆地西部地区天然气类型可划分为腐泥型气、腐殖型气、混合气3类,柴西北部天然气主要为腐泥型气和混合气,少量腐殖型气;柴西南部主要为腐泥型气,少量混合气。同时,建立了天然气成因类型的判识指标,对该区的天然气地球化学特征有了较为深入的认识,对今后的天然气勘探具有指导意义。     

电磁波SYT法在隐伏区寻找含金矿化 异常带中的应用

通常运用地质、地球物理以及钻探的方法来确定金属矿体的赋存状态,地球物理方法中常用的探测手段主要有地面伽玛能谱测量法、X射线荧光法、浅层地震、地电化学参数法和地电化学提取法等.SYT法接收反射回来的带有地下地质信息的电磁波,再经过特殊的数据处理而得到的反映地下地层物性特征的曲线和柱状,可以用来进行地质解释,运用该方法对山东牟平隐伏区的含金矿化异常带进行了探测研究,探测结果显示,在SYT法探测曲线中,含金矿化带有明显的异常特征,可以用来确定金属矿体的埋深和厚度.     

Numerical Modeling of Natural Fracture Distributions in Shale

The production efficiency of shale gas is affected by the interaction between hydraulic and natural fractures. This study presents a simulation of natural fractures in shale reservoirs, based on a discrete fracture network (DFN) method for hydraulic fracturing engineering. Fracture properties of the model are calculated from core fracture data, according to statistical mathematical analysis. The calculation results make full use of the quantitative information of core fracture orientation, density, opening and length, which constitute the direct and extensive data of mining engineering. The reliability and applicability of the model are analyzed with regard to model size and density, a calculation method for dominant size and density being proposed. Then, finite element analysis is applied to a hydraulic fracturing numerical simulation of a shale fractured reservoir in southeastern Chongqing. The hydraulic pressure distribution, fracture propagation, acoustic emission information and in situ stress changes during fracturing are analyzed. The results show the application of fracture statistics in fracture modeling and the influence of fracture distribution on hydraulic fracturing engineering. The present analysis may provide a reference for shale gas exploitation.     

一种冻土区天然气水合物地球化学勘查新技术——惰性气体氦氖分析

开发不受沼泽微生物影响的地球化学勘查技术是提高中纬度冻土区天然气水合物探井预测成功率的重要课题之一。本文选择在祁连山聚乎更天然气水合物已知区进行惰性气体勘查技术实验,研究了氦氖的测试方法,实验区为高寒沼泽景观,面积150km~2,采样密度2点/km~2,采样深度60cm,采集土壤顶空气样品300件和DK-3井岩芯样品400件,应用色谱反吹技术对顶空气样品进行了惰性气体氦氖的分析。结合地质和地球化学勘查成果进行了综合解释,认为惰性气体异常与天然气水合物矿藏关系密切,与烃类异常浓度范围一致,为顶部异常模式。实验区天然气水合物矿藏11个水合物发现井有10个位于He、Ne异常内,1个井位于异常外。分析了天然气水合物岩芯顶空气轻烃和氦氖指标的垂向分布特征,提出了天然气水合物矿藏上方土壤惰性气体的地气迁移机理。研究区近地表氦氖异常源于深部水合物矿藏和断裂构造,不受沼泽微生物的影响,是冻土区天然气水合物勘查的一种有效技术。     

Woolshed Creek fossil site: a key part of Canberra’s scientific and cultural heritage

The Woolshed Creek fossil site near the Royal Military College, Duntroon, Canberra, contains brachiopods Atrypa duntroonensis (early Homerian, early Silurian, ca 430.5?Ma) within a mudstone of the Canberra Formation. Their discovery in 1844 by the Reverend William B. Clarke (“the Father of Australian Geology”), and subsequent comparison with other fossil collections from around the world, contributed significantly to the nineteenth century debate about the oldest rocks in Australia. The fossil site is now on the ACT Government Heritage List and recent site improvements make it readily accessible via a pathway from the sports grounds of the Royal Military College.     

The Best Natural Boundary:a New Concept Developed by Combining the Sequence Boundary with the GSSP

Through a detailed study of sequence boundaries, it is concluded that sequence stratigraphy is an independent regional and transitional stratigraphic system between local lithostratigraphy and global chronostratigraphy. Therefore, a new tripartite stratigraphic classification scheme has been proposed. By combining organically the concept of sequence boundaries with the GSSP, it is suggested that the GSSP should be chosen in a conformale portion of a related sequence boundary, and the boundary established in light of this concept is defined as the Best Natural Boundary (BNB). The definition of the BNB points out the working area and stratigraphic level for the GSSP. By referring to a case study of the Permian Guadalupian/Lopingian boundary, the concept of the BNB has been elaborated in detail, and it is proposed that the BNB of the Guadalupian and the Lopingian lies between the Mesogondolella granti Zone and the Ctarkina postbitteri Zone, which is also the sequence chronostratigraphic boundary between th     

Impact cratering — fundamental process in geoscience and planetary science

Impact cratering is a geological process characterized by ultra-fast strain rates, which generates extreme shock pressure and shock temperature conditions on and just below planetary surfaces. Despite initial skepticism, this catastrophic process has now been widely accepted by geoscientists with respect to its importance in terrestrial — indeed, in planetary — evolution. About 170 impact structures have been discovered on Earth so far, and some more structures are considered to be of possible impact origin. One major extinction event, at the Cretaceous-Paleogene boundary, has been firmly linked with catastrophic impact, but whether other important extinction events in Earth history, including the so-called “Mother of All Mass Extinctions” at the Permian-Triassic boundary, were triggered by huge impact catastrophes is still hotly debated and a subject of ongoing research. There is a beneficial side to impact events as well, as some impact structures worldwide have been shown to contain significant (in some cases, world class) ore deposits, including the gold-uranium province of the Witwatersrand basin in South Africa, the enormous Ni and PGE deposits of the Sudbury structure in Canada, as well as important hydrocarbon resources, especially in North America. Impact cratering is not a process of the past, and it is mandatory to improve knowledge of the past-impact record on Earth to better constrain the probability of such events in the future. In addition, further improvement of our understanding of the physico-chemical and geological processes fundamental to the impact cratering process is required for reliable numerical modeling of the process, and also for the correlation of impact magnitude and environmental effects. Over the last few decades, impact cratering has steadily grown into an integrated discipline comprising most disciplines of the geosciences as well as planetary science, which has created positive spin-offs including the study of paleo-environments and paleo-climatology, or the important issue of life in extreme environments. And yet, in many parts of the world, the impact process is not yet part of the geoscience curriculum, and for this reason, it deserves to be actively promoted not only as a geoscientific discipline in its own right, but also as an important life-science discipline.     

厚层切叠砂体自然层描述方法:以北一区断东葡一组1-4小层为例

将多期切叠河道砂体归类合并,建立一个“垂向连续,横向联通的表外砂岩空间体”(其中砂岩间夹层厚度≤0.4 m)的自然层概念来控制多期河道复合切叠厚砂体。以北一匹断东萄一组1-4小层为例,利用自然层间砂体厚度、切叠程度、测井曲线形态、相叠加类型及砂体叠加期次将自然层分为5类;再依据砂体间切叠位置、切叠程度和切叠形态的差异建立自然层剖面表征方法;依据砂体叠加期次,建立自然层在平面上表征模式。     

矿泉水常识问答

矿泉水中的饮用天然矿泉水在地下深循环条件下形成,化学成分稳定,水源卫生,细菌学指标安全。有一定含量的矿物盐、微量元素或二氧化碳气体,作为一种天然饮料,是其他饮用水无法比拟的,无须医生指导,长期饮用也不会对人体产生危害。