黄土高原稳定同位素与古环境研究

黄土高原黄土地层已被证明是大陆上最完好的记录了过去环境信息的载体。通过黄土地层的碳,氧同位素作为气候替代指标研究古植被,降雨量,古环境温度及古季风演化方面取得了长足的进展,本文拟就主要研究成果作一综述,并对今后的研究方向做一前瞻。     

SAR图像保留边缘多窗口相干斑滤除方法

在处理合成孔径雷达（ＳＡＲ）图像中,精确地估计图像的局部统计特性和尽可能多地滤除相干斑都需要较大的窗口尺寸,而这与图像边缘和纹理结构的检测需要较小的窗口尺寸相矛盾。一般滤波器都是二者窗口尺寸的均衡,这必然导致二者都不能取得很好的效果。本文提出的新方法有效的解决了这一矛盾。此方法使处理后的ＳＡＲ图像既保存了边缘和纹理结构,避免了以往滤波器中使边缘变模糊的问题,又有效地滤除了相干斑噪声。     

油气成藏流体动力系统分析原理及应用

阐述了油气成藏流体动力系统分析的基本原理,把油气成藏流体动力系统分为重力驱动型、压实驱动型、滞流型和封存型四种类型。结合国内外的研究实例,分析了不同类型流体动力系统油气藏形成和分布的规律,强调在不同类型的流体动力系统中,油气藏形成的机理不同,在成藏动力学研究中有不同的侧重点。加强重力驱动型和封存型流体动力系统动力系统油气成藏条件研究对我国南方海相盆地和其它勘探程度较高的盆地深部的油气勘探具有重要意义。     

Metallogenetic characteristics of an unique uranium-tungsten mineralization zone

A polymetallic zone dominated by U-W mineralization was found in Northeast Guangxi. Distributed along the east contact zone of a complex granite mass, it extends for about 100 km in length, with more than fifty deposits and prospects embraced. The deposits show a wide range of genetic types, related to the granite, from magmatic (including pegmatite and skarn deposits) through hydrothermal mineralizations (hypo-, meso- and epithermal) all the way to tin placers, constituting a very intact metallogenetic series of granites. The epithermal U-W deposits are considered as a new type for their unique geological and geochemical characters, such as the paragenesis of U and W and the large time gap (> 40 Ma) between ore and granite. This project was financially supported by the Open Lab. of Ore Deposit Geochemistry, Chinese Academy of Sciences.     

Impact of sea spray on upper ocean temperature during typhoon passage: simulation with a 1-D turbulent model

At the interface between the lower atmosphere and sea surface, sea spray might significantly influence air-sea heat fluxes and subsequently, modulate upper ocean temperature during a typhoon passage. The effects of sea spray were introduced into the parameterization of sea surface roughness in a 1-D turbulent model, to investigate the effects of sea spray on upper ocean temperature in the Kuroshio Extension area, for the cases of two real typhoons from 2006, Yagi and Soulik. Model output was compared with data from the Kuroshio Extension Observatory (KEO), and Reynolds and AMSRE satellite remote sensing sea surface temperatures. The results indicate drag coefficients that include the spray effect are closer to observations than those without, and that sea spray can enhance the heat fluxes (especially latent heat flux) considerably during a typhoon passage. Consequently, the model results with heat fluxes enhanced by sea spray simulate better the cooling process of the SST and upper-layer temperature profiles. Additionally, results from the simulation of the passage of typhoon Soulik (that passed KEO quickly), which included the sea spray effect, were better than for the simulated passage of typhoon Yagi (that crossed KEO slowly). These promising 1-D results could provide insight into the application of sea spray in general circulation models for typhoon studies.     

Critical conditions for natural gas charging and delineation of effective gas source rocks for tight sandstone reservoirs

Although it has been shown that the potential of tight‐sand gas resources is large, the research into the mechanisms of hydrocarbon charging of tight sandstone reservoirs has been relatively sparse. Researchers have found that there is a force balance during hydrocarbon charging, but discriminant models still have not been established. Based on the force balance conditions observed during gas migration from source rocks to tight sandstone reservoirs, a calculation formula was established. A formula for identifying effective source rocks was developed with the gas expulsion intensity as the discrimination parameter. The critical gas expulsion intensity under conditions of various burial depths, temperatures, and pressures can be obtained using the calculation formula. This method was applied in the Jurassic tight sandstone reservoirs of the eastern Kuqa Depression, Tarim Basin, and it was calculated that the critical expulsion intensity range from 6.05 × 10⁸ m³/km² to 10.07 × 10⁸ m³/km². The critical gas charging force first increases with depth and later decreases with greater depths. The distribution range of effective gas source rocks and total expelled gas volume can be determined based on this threshold. This method provides new insight into and method for predicting favourable tight‐sand gas‐bearing regions and estimating their resource potentials. Copyright © 2014 John Wiley & Sons, Ltd.     

Hydrocarbon generation and expulsion characteristics of Lower Permian P1f source rocks in the Fengcheng area,northwest margin,Junggar Basin,NW China: implications for tight oil accumulation potential assessment

Combined with the actual geological settings, tight oil is the oil that occurs in shale or tight reservoirs, which has permeability less than 1 mD and is interbedded with or close to shale, including tight dolomitic oil and shale oil. The Fengcheng area (FA), at the northwest margin of the Junggar Basin, northwest China, has made significant progress in the tight oil exploration of the Fengcheng (P₁f) Formation recently, which indicates that the tight oil resources have good exploration prospects. Whereas the lack of recognition of hydrocarbon generation and expulsion characteristics of Permian P₁f source rocks results in the misunderstanding of tight oil resource potential. Based on the comprehensive analysis of geological and geochemical characteristics of wells, seismic inversion, sedimentary facies, tectonic burial depth, etc., the characteristics of P₁f source rocks were investigated, and the horizontal distributions of the following aspects were predicted: the thickness of source rocks, abundance and type of organic matter. And on this basis, an improved hydrocarbon generation potential methodology together with basin simulation techniques was applied to unravel the petroleum generation and expulsion characteristics of P₁f source rocks in FA. Results show that the P₁f source rocks distribute widely (up to 2039 km²), are thick (up to 260 m), have high total organic content (TOC, ranging from 0.15 to 4 wt%), are dominated by type II kerogen and have entered into low mature–mature stage. The modeling results indicate that the source rocks reached hydrocarbon generation threshold and hydrocarbon expulsion threshold at 0.5% Ro and 0.85% Ro and the comprehensive hydrocarbon expulsion efficiency was about 46%. The amount of generation and expulsion from the P₁f source rocks was 31.85 × 10⁸ and 15.31 × 10⁸ t, respectively, with a residual amount of 16.54 × 10⁸ t within the source rocks. Volumetrically, the geological resource of shale oil is up to 15.65 × 10⁸ t. Small differences between the amounts calculated by the volumetric method compared with that by hydrocarbon generation potential methodology may be due to other oil accumulations present within interbedded sands associated with the oil shales. Copyright © 2015 John Wiley & Sons, Ltd.     

Impact of Assimilating Radiances with the WRFDA ETKF/3DVAR Hybrid System on Prediction of Two Typhoons in 2012

The impacts of AMSU-A and IASI (Infrared Atmospheric Sounding Interferometer) radiances assimila-tion on the prediction of typhoons Vicente and Saola (2012) are studied by using the ensemble transform ...     

MJO预报研究进展

热带大气季节内振荡 (Madden-Julian oscillation,MJO) 是次季节-季节时间尺度气候变率的支配模态。它不仅对低纬度地区天气气候产生重要影响,还能够通过经向传播和激发大气遥相关波列对中高纬度地区产生影响,是延伸期尺度最重要的可预报性来源。因此,MJO预报是次季节-季节气候预测中极为重要的部分,近年来受到国际学术界广泛关注。该文回顾了MJO预报发展历史,概述了当前国际上主要科研业务机构的MJO预报发展现状。目前基于统计方法和气候模式的MJO预报研究取得了较大进展,特别是多个耦合气候模式和一种基于时空投影方法的统计模型均能够显著提升MJO预报技巧 (有效预报可达20 d以上)。该文还介绍了中国气象局国家气候中心在MJO预报技术发展和业务系统研制方面的新进展,当前基于第2代大气环流模式的MJO业务预报填补了国内空白,技巧为16~17 d,而耦合气候模式试验的技巧已达到约20 d。总体来看,利用耦合模式预报MJO是未来发展的主要方向,其中,面向MJO的模式初始化和集合预报新方法研究将是关注重点。     

浅谈长庆油田裸眼井测井仪器遇卡及处理方法

本文对长庆油田测井仪器遇卡的种类、遇卡的具体原因、预防遇卡事故的措施、解卡的处理方法及解卡的理论分析等方面进行了阐述,主要目的是提高测井效率,降低安全风险,确保裸眼井筒作业优质高效.