塔里木轮南油田三叠系层序与岩性圈闭

塔里木板块轮南井区三叠系为典型的克拉通内凹陷盆地型陆相碎屑岩,主要由湖泊和三角洲沉积体系构成产油层系。层序单元的划分对比是岩性油气藏圈定的核心技术,以测井和三维地震资料为依据建立井震合一的层序地层格架,所划分的3个层序8个体系域控制了三套区域性和多套局部性储盖组合。区域性储盖组合以层序为单元,层序下部的低位体系域和湖侵体系域砂岩组成区域性储层,上部高位体系域的湖相和三角洲相泥岩为区域性盖层,以构造圈闭为主;局部性储盖组合以体系域为单元,由同一体系域的砂岩和邻近泥岩组成,以岩性圈闭为主。结合地震储层预测技术可划定新的岩性地层圈闭,高位体系域期和湖侵体系域中发育的局部性储盖组合是岩性地层圈闭勘探的重点。     

酸消解-车载偏振能量色散X射线荧光法现场测定祁曼塔格多金属矿中高品位铜铅锌

能量色散X射线荧光光谱法(ED-XRF)是勘查与找矿现场常用的分析手段.对于高矿化度样品或矿石样品,由于存在严重的基体效应,难以找到与基体匹配的校准样品,分析数据的准确度会受到严重影响,乃至给出错误的结果,成为制约现场分析高矿化度地质样品的主要难题.本文针对XRF现场分析高矿化样品存在的问题,研制了两种具有双层薄膜结构的液体样品盒,以强酸性溶液进样,应用车载台式偏振激发能量色散X射线荧光光谱(PE-EDXRF)技术,采用标准溶液进行含量校准,二级靶钼Kα谱线的康普顿散射峰作为内标校正基体效应,实现了现场准确分析青海祁曼塔格高原矿区铜铅锌多金属矿石中的铜、铅、锌三种元素.为制备适合PE-EDXRF分析的溶液,在祁曼塔格矿区现场对实验室管理样及未知样品试验了水浴加热与电热板加热两种样品处理方式.采用电热板加热方式,分析2件矿区样品的方法精密度(RSD,n=10)均优于2％;分析4件管理样的方法准确度均优于5％(当含量＞5‰时);13件矿区未知样品PE-EDXRF与原子吸收分光光度法(AAS)分析结果的平均相对偏差为:Cu 2.87％(含量范围在0.75％～8.57％),Pb 2.82％(含量范围在0.78％ ～29.1％),Zn 6.84％(含量范围在0.11％ ～2.51％),两种方法的分析结果具有很好的一致性.而采用水浴加热方式消解样品,由于在海拔四千多米地区水的沸点仅约为88℃C,样品消解不够完全,导致测定结果系统偏低.现场实验和结果表明,在高原低气压环境下,采用电热板加热方式消解样品,结合使用双层膜液体样品盒建立的PE-EDXRF分析方法,可以解决高矿化度样品及矿石样品的较高精度现场分析问题.本文建立的溶液制样方法可以解决基体匹配的难题,结合使用研制的双层膜溶液样品盒保护了仪器,是对粉末制样法PE-EDXRF现场分析技术的一个补充和完善.     

关于密西西比河谷型(MVT)铅锌矿床的一些探讨

密西西比河谷型(MVT)铅锌矿床是全球最重要的铅锌矿床类型之一,由于其储量大、开发早,在成矿规律研究等方面均取得了重要进展,如成矿物质来源、成矿流体的驱动机制、成矿金属的迁移机制和沉淀富集机制、成矿时代、成矿模式等。文章在总结前人研究成果的基础上,主要从含矿建造和区域盆地卤水活动两个方面对MVT矿床的成矿规律进行了系统的总结和综合研究,厘定了MVT矿床的含矿建造,主要包括特定的含矿岩性组合、盆地中的红层、生烃层等,分析了区域盆地卤水活动对MVT矿床的制约,主要包括区域白云石化与MVT铅锌矿床的空间分布关系、与MVT铅锌矿床常伴生的其他类型矿床,并对MVT铅锌矿床的成因进行了初步的探讨。最后,认为特定的岩性组合(特别是砂岩、碳酸盐岩、泥页岩组合)、含矿岩系下部碎屑岩的褪色蚀变、区域红层盆地的广泛发育、生烃盆地的边缘、区域白云石化的前锋地带等,是MVT矿床及其伴生矿床找矿勘探的重要参考依据。     

徐州地区寒武系豹皮灰岩的岩性特征及其成因机制分析

徐州地区的寒武系地层岩性主要以碳酸盐岩为主,地层中出现多层厚层状豹皮灰岩。对于寒武系豹皮灰岩的岩性特征研究可为当地古地理环境的判断和还原提供依据;基于近年来发现碳酸盐岩具有油气显示,对豹皮灰岩进行综合分析具有一定的地质油气意义。对徐州地区寒武系地层中豹皮灰岩的岩性特征进行了研究,并在此基础上对其成因进行了仔细分析,表明了豹皮灰岩的白云岩化作用发生在成岩早期,在低盐度混合水动力条件下回流渗透白云岩化成岩。     

岩浆热液矿床最佳成矿部位探讨

与花岗质岩浆有关的热液矿床最佳成矿部位是一个具有探索性的课题,它依据的理论是:与花岗岩有关的热液成矿作用是一系列复杂的化学反应过程;它有两个前提:成矿是中—低温化学反应导致成矿元素沉淀的产物;成矿作用不同程度与大气水的加入有关。热液矿床形成于地壳浅部,限定在大气水临界面(critical plane of the meteoric water)和成矿上限临界面(critical plane of the mineralization upper limit)之间。来自深部的含矿热液抵达这个部位,物理化学条件发生了急剧变化,可能引发剧烈的化学反应,中—低温环境和地表水的加入则有利于成矿元素的沉淀,遂使该带成为最有利于成矿的部位。大气水临界面是大气水向下循环的下界,是一个极不规则的界面,主要受地表水供应量、温度、岩性、构造等因素的制约。成矿上限临界面主要受温度和隔档层的制约,尤其隔档层,可能是某些大型和超大型矿床的聚集地。无水不成矿,无地下水不成矿,看来是有道理的。探讨与花岗岩有关的热液金属矿床的最佳成矿部位对于指导深部找矿是有意义的。     

黔北铝土矿矿带基底岩系组成及空间分布与成矿作用的关系探讨

贵州省北部铝土矿分布于黔中-渝南铝土矿成矿带的南段北部,成矿地质条件较好。通过分析黔北不同矿带基底地层岩性差异、矿体分布、矿床规模和成矿物质来源等因素之间的相互关系,探讨了铝土矿矿床下伏基底地层岩性对黔北铝土矿的控制作用。研究表明,基底地层古风化地貌的空间变化控制着铝土矿的矿体分布和矿体规模,而基底地层的岩性特征决定了所形成矿床的矿石质量。     

多参数岩性反演在煤田地震勘探中的应用

基于模型的常规地震反演方法,利用声速或密度测井曲线进行约束从而获得波阻抗信息.但是,当目的层与围岩的波阻抗差异很小时,根据波阻抗信息很难解决层位对比问题.实际上,视电阻率、自然伽马等测井曲线可以提供其他的地层岩性信息,利用多参数进行约束反演对区分岩性更加敏锐.双测井曲线融合法将密度和视电阻率测井曲线融合、变换后得到一条拟密度曲线,该曲线同时突出了煤层与岩浆岩的密度和电阻率异常.利用该曲线进行约束,可以实现多参数岩性反演.     

雷达图分析法在测井解释中的应用

应用雷达图分析法进行相识别,将未取芯井测井相曲线与标准井测井相曲线叠加,通过曲线差异对比法或面积法来识别未知井储层岩性或含油气性.详细阐述了雷达图分析方法的原理,给出了雷达图绘图软件运行流程,并利用实例加以验证.实践证明:在测井解释中,雷达图分析法可以较为精确地确定井剖面地层岩性,识别储层流体;绘图软件可以有效地辅助完成地层测井响应特征的对比分析.     

Optical properties of estuarine dissolved organic matter isolated using cross-flow ultrafiltration

Dissolved organic matter(DOM) from freshwater, mid-salinity, and seawater endmember samples in the Jiulong River Estuary, China were fractionated using cross-flow ultrafiltration with a 10-kDa membrane. The colloidal organic matter(COM; 10 kDa–0.22 μm) retentate, low molecular weight(LMW) DOM(10 kDa) permeate, and bulk samples were analyzed using absorption spectroscopy and three-dimensional fluorescence excitation-emission-matrix spectroscopy. The UV-visible spectra of COM were very similar to those obtained for permeate and bulk samples, decreasing monotonically with increasing wavelength. Most of the chromophoric DOM(CDOM, expressed as the absorption coefficient a355) occurred in the LMW fraction, while the percentage of CDOM in the colloidal fraction was substantially higher in the freshwater endmember(13.4% of the total) than in the seawater endmember(6.8%). The bulk CDOM showed a conservative mixing behavior in the estuary, while there was removal of the COM fraction and a concurrent addition of the permeate fraction in the mid-salinity sample, implying that part of the colloidal CDOM was transformed into LMW CDOM. Two humic-like components(C1: 250, 325/402 nm; and C2: 265, 360/458 nm) and one protein-like component(C3: 275/334 nm) were identified using parallel factor analysis. The contributions of the C1, C2, and C3 components of the COM fraction to the bulk sample were 2.5%–8.7%, 4.8%–12.6%, and 7.4%–14.7%, respectively, revealing that fluorescent DOM occurred mainly in the LMW fraction in the Jiulong River Estuary. The C1 and C2 components in the retentate and permeate samples showed conservative mixing behavior, but the intensity ratio of C2/C1 was higher in the retentate than in the permeate fractions for all salinity samples, showing that the humic component was more enriched in the COM than the fulvic component. The intensity ratio of C3/(C1+C2) was much higher in the retentate than in the permeate fraction for mid-salinity and seawater samples, revealing that the protein-like component was relatively more enriched in COM than the humic-like component. The contribution of the protein-like component(C3) to the total fluorescence in the retentate increased from 14% in the freshwater endmember to 72% for the seawater endmember samples, clearly indicating the variation of dominance by the humic-like component compared to the protein-like component during the estuarine mixing process of COM.     

Calculation and experiment for dynamic response of bridge in deep water under seismic excitation

The fluid-structure interaction under seismic excitation is very complicated, and thus the damage identification of the bridge in deep water is the key technique to ensure the safe service. Based on nonlinear Morison equation considering the added mass effect and the fluid-structure interaction effect, the effect of hydrodynamic pressure on the structure is analyzed. A series of underwater shaking table tests are conducted in the air and in water. The dynamic characteristics affected by hydrodynamic pressure are discussed and the distribution of hydrodynamic pressure is also analyzed. In addition, the damage of structure is distinguished through the natural frequency and the difference of modal curvature, and is then compared with the test results. The numerical simulation and test of this study indicate that the effect of hydrodynamic pressure on the structure should not be neglected. It is also found that the presence of the damage, the location of the damage and the degree of the severity can be judged through the variation of structure frequency and the difference of modal curvature.