四川盆地资阳地区龙王庙组优质储层识别与分布预测

四川盆地资阳地区龙王庙组局限台地台内滩沉积厚度薄,且在工区西北部剥蚀尖灭,有效识别资阳地区龙王庙组优质储层分布是油气取得突破的关键。基于ZY1井及三维地震资料,在储层精细标定及层位解释基础上,首先利用地震相及振幅属性刻画有利的沉积相带,再结合分频属性及波阻抗反演确定有利储层的边界及厚度,最终利用古地貌及裂缝预测确定优质白云岩储层的空间分布规律。综合预测结果表明,资阳地区龙王庙组储层纵向上主要分布在中上部,横向上主要发育两个呈北东向条带状展布的滩体。工区西北部位于二叠系沉积前的古地貌高部位,且暴露剥蚀区更易形成有利的溶蚀孔隙型白云岩储层,是有利的油气聚集区带。     

青藏高原南部乌郁盆地渐新世—上新世地层沉积相分析

青藏高原南部乌郁盆地是欧亚与印度板块碰撞以来冈底斯山隆升最具代表性的盆地之一,也是青藏高原南部较大的新生代残留盆地之一。沉积盆地中保存着完整的渐新世—早更新世连续沉积记录,自下而上由古新世—始新世林子宗群（典中组、年波组和帕那组）、渐新世—中新世日贡拉组、中新世芒乡组、来庆组、上新世—早更新世乌郁群（乌郁组、达孜组）,总厚度大于4180m。林子宗群为一套中—酸性钙碱性火山岩系,夹紫红色砂岩、砾岩及粉砂岩。日贡拉组主要为紫红色砂岩、砾岩,夹少量火山熔岩及酸性火山凝灰岩,为一套山间盆地沉积。芒乡组为灰色、深灰色泥岩、砂岩,夹煤和油页岩,为湖泊相—前三角洲相—沼泽相。来庆组为一套褐色安山岩、火山碎屑岩。乌郁组是一套碎屑岩,颜色呈灰色、灰褐色,夹煤及油页岩,为山间盆地辫状河—湖泊—沼泽沉积。达孜组是一套黄褐色砾岩、砂砾岩、砂岩,夹少量泥岩,发育铁质结核,为辫状河沉积。沉积相分析表明具有明显的古新世—始新世林子宗群（典中组、年波组和帕那组）、渐新世—中新世日贡拉组—芒乡组、中新世来庆组—上新世乌郁组、上新世—早更新世达孜组四个阶段式隆升—剥蚀过程。从芒乡组的潮湿炎热的气候转变为乌郁组的干燥凉爽,显然与青藏高原隆升密切相关。乌郁盆地渐新世—早更新世沉积相分析对于研究青藏高原隆升和油气等能源均具有重要意义。      

坦桑尼亚某金矿的磁力、激电异常特征

坦桑尼亚某金矿是与条带状含铁建造(BIF)有关的隐伏金矿床.为了查明该金矿脉的分布情况,开展了地面高精度磁力勘查.△T异常特征以负异常为主,负异常峰值大于正异常,正异常为伴生异常,总体上反映了BIF在平面上的延伸方向和构造方向特征;激电测深断面异常以视电阻率等值线“下凹”、视极化率等值线“上凸”为表现形式,二者分别反映了断面内的构造位置和BIF形态特征.本区磁力和激电异常对BIF体的隐伏特征反映的均很明显,依据二者的测量成果,进行钻孔定位,指导钻探施工,钻遇了目的层,收到了很好的效果.     

The“Sand-Mud” Sedimentary Record and Its Diagenetic System in Shore-shallow Lacustrine—A Case Study of Eocene Kongdian Formation in Jiyang Depression

The sand-mud sedimentary record develops widely in the shore-shallow lacustrine, which can be a good oil and gas reservoir cap combination. It has important significance in petroleum geology. This paper takes the Kongdian Fm. of Eocene in Jiyang Depression as an example to study the formation mechanism and diagenetic system of the sand-mud sedimentary record in the shore-shallow lacustrine. The study indicated that sandstone-mudstone sedimentary strata at macroscopic level includes sand-mud duality, mudstone vein and sandstone lens in the Kongdian Fm. of Jiyang Depression, and there are some transitional clastic rocks at the microscopic level (Clastic particles, clay and carbonate cements are included in the transitional clastic rocks). The sandstone-mudstone sedimentary strata mainly formed in the material transformation of the shallow-water deltas and conjugate shock in the shore-shallow lacustrine. The thickness is mainly restricted by material source and water dynamic condition, and the sand-mud transitional clastic rocks are restricted by the dynamic mechanism and sedimentary differentiation of the lake water. The sandstone-mudstone sedimentary strata is composed of a closed diagenetic system. Early compaction-drainage and differential compaction, middle and late clay mineral transformation, structural water and organic acid emissions during the diagenetic process of mudstone influence the diagenesis of sandstone. The closed diagenetic system of sand-mud transitional clastic rocks is mainly related to the structural maturity of clastic rocks.     

Pore Structure Heterogeneity of the Xiamaling Formation Shale Gas Reservoir in the Yanshan Area of China: Evaluation of Geological Controlling Factors

Micro-heterogeneity is an integral parameter of the pore structure of shale gas reservoir and it forms an essential basis for setting and adjusting development parameters. In this study, scanning electron microscopy, high-pressure mercury intrusion and low-temperature nitrogen adsorption experiments were used to qualitatively and quantitatively characterize the pore structure of black shale from the third member of the Xiamaling Formation in the Yanshan area. The pore heterogeneity was studied using fractal theory, and the controlling factors of pore development and heterogeneity were evaluated in combination with geochemical parameters, mineral composition, and geological evolution history. The results show that the pore structure of the reservoir was intricate and complicated. Moreover, various types of micro-nano scale pores such as dissolution pores, intergranular pores, interlayer pores, and micro-cracks are well developed in member 3 of the Xiamaling Formation. The average porosity was found to be 6.30%, and the mean value of the average pore size was 4.78 nm. Micropores and transition pores provided most of the storage space. Pore development was significantly affected by the region and was mainly related to the total organic carbon content, vitrinite reflectance and mineral composition. The fractal dimension, which characterizes the heterogeneity, is 2.66 on average, indicating that the pore structure is highly heterogeneous. Fractal dimension is positively correlated with maturity and clay mineral content, while it is negatively correlated with brittle mineral content and average pore size. These results indicate that pore heterogeneity is closely related to thermal history and material composition. Combined with the geological background of this area, it was found that the pore heterogeneity was mainly controlled by the Jurassic magmatism. The more intense the magma intrusion, the stronger the pore heterogeneity. The pore structure and its heterogeneity characteristics present today are a general reflection of the superimposed geological processes of sedimentary-diagenetic-late transformation. The influence of magmatic intrusion on the reservoir is the main geological factor that should be considered for detailed evaluation of the Xiamaling Formation shale gas reservoir in the Yanshan area.     

Pollen evidence for variations in the southern margin of the westerly winds in SW Patagonia over the last 12,600 years

We report pollen and charcoal records from Vega Ñandú ( 51°0′S, 72°45′W), a small mire located near the modern forest-steppe ecotone in Torres del Paine National Park, southern Chile. The record shows an open landscape dominated by low shrubs and herbs between 12,600 and 10,800 cal yr BP, under cold and relatively humid conditions. Nothofagus experienced frequent, large-amplitude oscillations between 10,800 and 6800 cal yr BP, indicating recurrent transitions between shrubland/parkland environments, under warm and highly variable moisture conditions. A sustained increase in Nothofagus started at 6800 cal yr BP, punctuated by step-wise increases at 5100 and 2400 cal yr BP, implying further increases in precipitation. We interpret these results as indicative of variations in the amount of precipitation of westerly origin, with prominent increases at 6800, 5100, and 2400 cal yr BP. These pulses led to peak precipitation regimes during the last two millennia in this part of SW Patagonia. Our data suggest variations in the position and/or strength of the southern margin of the westerlies, most likely linked to variations in the extent and/or persistence of sea ice and sea-surface temperature anomalies in the Southern Ocean. Over the last two centuries the record shows a forest decline and expansion of Rumex acetosella, an exotic species indicative of European disturbance.     

Evaluation of redox-sensitive metals in marine surface sediments influenced by the oxygen minimum zone of the Humboldt Current System,Northern Chile

Upwelling coastal systems can be used to understand how dissolved oxygen and biological productivity control the accumulation of redox-sensitive metals in marine sediments. The aluminium (Al), cadmium (Cd), iron (Fe), nickel (Ni), molybdenum (Mo), vanadium (V), total organic carbon (TOC), total nitrogen (TN) and total sulfur (TS) contents in surficial sediment collected from different water depths (30, 70, and 120?m) in three northern Chilean bays influenced by coastal upwelling and oxygen minimum zones (OMZs) were measured. Principal component analysis (PCA), cluster analysis, and Spearman?s rank correlation were used to identify the mechanisms responsible for the redox-sensitive metal accumulation. The content of redox-sensitive metals and organic components in sediment increased with increasing water column depth, whereas lithogenic metals decreased. In the Mejillones del Sur and Caldera bays, the enrichment factors of the redox-sensitive metals showed enrichment for all metals with depth. The Cd and V enrichments are mainly the product of biogenic flow to the seabed, and the Mo and Ni enrichments are due to preservation under low subsurface oxygen conditions. Sulfate reduction is not an important mechanism in the accumulation of redox-sensitive metals in the sediment of the three bays. The PCA showed that the behaviors of the redox-sensitive metals and organic components reflect differences in the effects of the OMZ in sediment along the coast of northern Chile, with a more intense OMZ in Mejillones del Sur bay and weaker OMZs in Caldera and Inglesa bays. However, the high degree of enrichment in redox-sensitive metals in Caldera Bay can be attributed to the intense activity of the mining industry near the bay, a situation that produces geochemical behavior similar to that observed in Mejillones del Sur Bay.     

盾形陀螺珊瑚与根枝藻和点斑篮子鱼之间相互作用的实验研究

本研究通过120d的室内培养实验研究了盾形陀螺珊瑚（Turbinaria peltata）、根枝藻（Rhizoclonium sp．）和点斑篮子鱼（Siganus guttatus）之间的相互作用关系．结果显示,高质量浓度的NO3-（5．00～10．00mg／dm3）刺激了丝状绿藻根枝藻在缸内的爆发式生长,在实验27d时根枝藻在缸壁的面积覆盖率达到90．5％,藻丝长度为10～15cm．在海藻的胁迫作用下,盾形陀螺珊瑚的PSⅡ最大光化学量子产量（Fv／Fm）均值逐渐从0．712降至0．626,降幅为10．7％～13．5％．放入4尾4～6cm长的点斑篮子鱼后,实验缸壁根枝藻的面积覆盖率在2d内从90．5％下降至10．0％．但解除根枝藻胁迫后盾形陀螺珊瑚的Fv／Fm值并没有明显变化,与对照组的差异也不显著;随着海藻胁迫因子的消除,盾形陀螺珊瑚的Fv／Fm值逐渐升高,并在第120天时恢复至初始状态．本研究结果从珊瑚光合作用效率的角度验证了啃食者的存在确能缓解富营养化对造礁珊瑚的不利影响,为“下行控制假说”提供了新的证据．     

越冬浮游植物光合作用活性的原位研究

水体中浮游植物在越冬期间数量少,关于湖泊中越冬浮游植物如蓝藻、绿藻、硅藻等浮游植物的光合作用活性情况少见报道.本实验通过Phyto-PAM(Pulse Amplitude Modulation)对最大光量子产量Fv/Fm(可变荧光和最大荧光之比)和快速光曲线的测定,结合显微镜镜检结果,并在室内进行了硫酸铜处理以及鲁哥氏液处理实验,对太湖、巢湖和玄武湖处于越冬期间的浮游植物进行了原位光合作用活性的研究.显微镜镜检结果表明太湖和玄武湖水体中以绿藻和硅藻为主,而蓝藻很少,巢湖水体中有大量蓝藻、绿藻和硅藻.Phyto-PAM在对玄武湖和太湖水样原位测定时未检测出蓝藻,而绿藻和硅藻有光合作用活性,其Fv/Fm在0.5左右;对巢湖的水体检测到的蓝藻、绿藻、硅藻都具有光合作用活性,其中绿藻和硅藻的Fv/Fm在0.5左右,蓝藻的Fv/Fm在0.3左右;用硫酸铜处理实验在巢湖水样中发现水体仅有硅藻活性(Fv/Fm下降至0.2左右),而用鲁哥氏液处理后无任何藻类光合作用活性.上述实验结果表明,即使处于越冬期间,以较多数量出现在水体中的蓝藻、绿藻和硅藻仍然具有较高的光合作用活性.