The Heterogeneities and Reservoirs Characterization of Shahezi Formation Tight Gas in Xujiaweizi Fault Depression

<正>The tight sandstone gas prospecting is a key area of unconventional oil and gas exploration.The source rock of Shahezi Formation indicates adequate source condition for gas,which shows features of great thickness,wide distribution,high organic content and remaining high and overmature stages.Meantime,it possesses a reservoir condition with low porosity and low permeability,a     

A New Species of Rhodoleia (Hamamelidaceae) from the Upper Pliocene of West Yunnan, China and Comments on Phytogeography and Insect Herbivory

In Europe, fossil fruits and seeds of Rhodoleia (Hamamelidaceae) have been described from the Upper Cretaceous to the Miocene, whereas no fossil record of Rhodoleia has been reported in Asia, where the modern species occur. Herein, 21 fossil leaves identified as Rhodoleia tengchongensis sp. nov. are described from the Upper Pliocene of Tengchong County, Yunnan Province, Southwest China. The fossils exhibit elliptic lamina with entire margins, simple brochidodromous major secondary veins, mixed percurrent intercostal tertiary veins, and looped exterior tertiaries. The leaf cuticle is characterized by pentagonal or hexagonal cells, stellate multicellular trichomes, and paracytic stomata. The combination of leaf architecture and cuticular characteristics suggests that the fossil leaves should be classified into the genus Rhodoleia. The fossil distributions indicate that the genus Rhodoleia might originate from Central Europe, and that migrated to Asia prior to the Late Pliocene. Additionally, insect damage is investigated, and different types of damage, such as hole feeding, margin feeding, surface feeding, and galling, are observed on the thirteen fossil leaves. Based on the damage frequencies for the fossil and extant leaves, the specific feeding behavior of insects on Rhodoleia trees appears to have been established as early as the Late Pliocene. The high occurrence of Rhodoleia insect herbivory may attract the insect-foraging birds, thereby increasing the probability of pollination.     

Structural Evolution and Hydrocarbon Potential of the Upper Paleozoic Northern Ordos Basin, North China

The hydrocarbon potential of the Hangjinqi area in the northern Ordos Basin is not well known, compared to the other areas of the basin, despite its substantial petroleum system.Restoration of a depth-converted seismic profile across the Hangjinqi Fault Zone(HFZ) in the eastern Hangjinqi area shows one compression that created anticlinal structures in the Late Triassic, and two extensions in ~Middle Jurassic and Late Early Cretaceous, which were interrupted by inversions in the Late Jurassic–Early Early Cretaceous and Late Cretaceous, respectively.Hydrocarbon generation at the well locations in the Central Ordos Basin(COB) began in the Late Triassic.Basin modeling of Well Zhao-4 suggests that hydrocarbon generation from the Late Carboniferous–Early Permian coal measures of the northern Shanbei Slope peaked in the Early Cretaceous, predating the inversion in the Late Cretaceous.Most source rocks in the Shanbei Slope passed the main gas-migration phase except for the Hangjinqi area source rocks(Well Jin-48).Hydrocarbons generated from the COB are likely to have migrated northward toward the anticlinal structures and traps along the HFZ because the basin-fill strata are dipping south.Faulting that continued during the extensional phase(Late Early Cretaceous) of the Hangjinqi area probably acted as conduits for the migration of hydrocarbons.Thus, the anticlinal structures and associated traps to the north of the HFZ might have trapped hydrocarbons that were charged from the Late Carboniferous–Early Permian coal measures in the COB since the Middle Jurassic.     

In Situ Analyses of Trace Elements,U–Pb and Lu–Hf Isotopes in Zircons from the Tongshankou Granodiorite Porphyry in Southeast Hubei Province,Middle-Lower Yangtze River Metallogenic Belt,China

The Tongshankou Cu-Mo deposit, located in southeast Hubei province, is a typical skarn–porphyry type ore deposit closely related to the Tongshankou granodiorite porphyry, characterized by a high Sr/Y ratio.Detailed in situ analyses of the trace elements and U–Pb and Lu–Hf isotopes in zircons from the Tongshankou granodiorite porphyry were performed.Scarcely any inherited zircons were observed, and the analyzed zircons yielded highly concordant results with a weighted mean 206Pb/238 U age of 143.5 ± 0.45 Ma(n=20, mean square weighted deviation was 0.75), which was interpreted to represent the crystallization age of the Tongshankou granodiorite porphyry.The chondrite-normalized rare-earth element pattern was characterized by a slope that steeply rises from the light-group rare-earth elements(LREE) to the heavy-group rare-earth elements(HREE) with a positive Ce-anomaly and inconspicuous Eu-anomaly, which was coincident with the pattern of the zircons from the Chuquicamata West porphyry, Chile.The analyzed zircons also had relatively low 176Hf/177 Hf ratios of 0.282526–0.282604.Assuming t=143 Ma, the corresponding calculated initial Hf isotope compositions(εHf(t)) ranged from-5.6 to-2.9.The results of the in situ analysis of trace elements and U–Pb and Lu–Hf isotopes in zircons from the Tongshankou granodiorite porphyry suggest that a deep-seated process involving a thickened-crust/enriched-mantle interaction may play an important role in the generation of high Sr/Y-ratio magma and potentially in the generation of porphyry Cu-Mo systems.     

Metallogenic Prediction of the Peripheral Areas of the Xiyi Concealed Lead-Zinc Deposit in Baoshan City, Yunnan Province

<正>The newly-discovered Xiyi lead-zinc deposit is a large deposit located in the north central Baoshan block of the southern Sanjiang metallogenic belt section,Southwest China.The surface of the deposit is mainly covered by     

甘肃花草滩煤矿区沉积相演化与内部构造的地质意义探讨

花草滩煤矿区地处北祁连褶皱带中段北侧,酒东盆地东端。古生界和中生界地层在区内发育较完整,其中石炭系太原组为含煤地层。经二、三维地震勘探、钻探等工作证实矿床总体上受单斜构造控制。石炭纪中期盆地呈逐渐上升趋势,沉积相演化经历了由海相逐渐过渡到海陆交汇相,再到陆相沉积的阶段。F5和F8断层具顺层断裂特征,破坏煤层的连续性,在一定程度上控制了瓦斯突出区的分带,可作为煤矿瓦斯含量高低的分界标志。     

内蒙古达茂旗阿拉格敖包地区英云闪长岩地球化学特征及构造背景

内蒙古达茂旗阿拉格敖包地区位于华北板块北缘增生带。对区内英云闪长岩岩石地球化学研究表明:岩石具有较低的w(SiO2)(68.71%~70.53%)和较高的w(Al2O3)(13.82%~14.42%),贫碱(w(Na2O+K2O)=5.69%~6.37%)、富钠贫钾(Na2O/K2O=6.29~9.40)的特点,A/CNK值为0.98~1.26,显示铝弱饱和;岩石稀土总量较低(89.2×10-6~132.94×10-6),轻重稀土分馏不明显[(La/Yb)N=2.75~4.57],具有弱的负铕异常和负铈异常;相对富集不相容元素Rb,Th,U,LREE,亏损Ba,Ta,Nb,Sr,P,Ti等高场元素;属准铝质-弱过铝质低钾I型花岗岩。分析表明,英云闪长岩总体经历了较低程度的部分熔融和结晶分异,源区为下地壳基性岩部分熔融,同时混有地壳物质;构造环境为内陆造山环境,指示华北板块与西伯利亚板块在二叠纪末已完全闭合,英云闪长岩是在造山后的伸展环境下,地幔上涌与地壳中具有洋壳性质的岩石相互作用而形成,具有岛弧花岗岩性质,为滞后型岩浆岩,代表了岩浆来源具有壳幔混合的特征。     

多孔黏弹介质平面波理论及波场数值模拟

本文将黏弹固体骨架与各向异性多孔弹性模型相结合,并将地层黏弹性的特性考虑其中,更好地刻画了快P波和横波在地震频带的衰减现象。将多孔黏弹模型模拟结果同传统弹性模型模拟结果对比显示,多孔黏弹模型在模拟真实储层方面更具优势。     

基于窗口理论的时频分析方法研究

通过对比短时Fourier变换、连续小波变换、S变换、广义S变换等时频分析方法发现,从窗的维度看,它们具有统一的内积形式,差别在于窗函数中σ(f)的取值。通过分析相应方法中σ(f)随信号频率的变化规律,以及随之产生的时窗与时频分辨率问题,解释广义S变换的相对优越性。将广义S变换应用于四类薄互层模型,研究薄互层时频特性与地质特性的对应关系,指导地层旋回方向的预测。     

岩石本构模型智能辨识方法研究

岩石本构模型是研究岩石力学特征和变形机制的基础,而本构模型或模型中相关参数的识别是本构模型研究中的热点和难点问题。本文基于红板岩室内力学实验数据,分别利用遗传算法、BP神经网络以及遗传规划对红板岩本构模型进行了模式识别,结果表明,遗传算法进行参数识别需要事先假定流变模型的形式,误差较大,而BP神经网络和遗传规划可以一次性同时确定流变模型的结构形式及参数,有效避免模型假定所带来的误差。而遗传规划与BP神经网络相比,具有精度高、收敛快,可视化程度高等特点,为岩石本构参数及模型的智能识别方法的选取提供参考。