利用NMR技术判识混油钻井液条件下钻遇的油层

混油钻井液对色谱、光谱录井技术发现和评价油气层带来了严重影响.为了准确识别和定量评价混油钻井液条件下所钻遇的油层,创新采用高分辨率核磁共振录井技术随钻检测钻井液T2谱及其含油率的变化.不同油品在钻井液中的混合实验结果表明,混油钻井液为水包油乳液,两种不同的油品在钻井液中难以混合,在T2谱上呈现相互独立的峰,据此可以直观、准确地识别所钻遇的油层;并可根据归一法、外标法定量评价钻井液中的地层油含油率.经现场应用,取得了与室内实验相一致的效果,证明了该项技术的有效性.     

利用磁共振技术检测钻井液含油量的方法探讨

含油气的岩层被钻开以后,其中的油气一部分保留在岩样中,另一部分则进入钻井液,岩样中的油、气及钻井液中的气都有相应的录井方法来检测,唯独钻井液中的油一直是录井检测的空白. 随着油气勘探程度的加深及钻井工艺技术的发展,岩屑含油级别低甚至无显示、气测异常幅度低甚至无异常的油井是越来越多,导致油气层的发现与评价变得十分困难. 因此,急需对钻井液中的含油量进行随钻检测. 通过对不同油质、 不同含油量的钻井液进行磁共振试验,结果表明,可以通过核磁共振一维谱(T₂谱)实现轻～中质油的含油量分析,通过二维谱(T₂-D谱)以实现对重质油的含油量分析. 该项研究对于完善录井技术系列、提高油层发现率和评价准确率具有十分重要的意义.     

固体核磁共振技术在水泥基材料研究中的应用

水泥基材料组分、结构复杂,其水化过程、水化产物组成和结构表征是研究中的难点.一维固体核磁共振谱图可定性或定量分析胶凝材料（水泥及矿物掺合料）的水化程度、水化产物（特别是非晶相）的种类和结构,从而揭示胶凝材料的组成、外加剂和环境等因素对水泥基材料水化过程的影响.而二维核磁共振谱可进一步研究不同或同种原子核之间的连接情况,从而明确水化产物中的掺杂、取代,以及有机外加剂在水泥浆体中的分散情况.因此,固体核磁共振技术可获取其它方法难以获得的信息,有力促进水泥水化及其微观结构的研究.     

两种取代咔咯的合成与表征

以吡咯和3-硝基苯甲醛为原料,在无溶剂、无催化剂条件下固相合成了5,10,15-三(3-硝基苯基)咔咯(a),然后利用SnCl2还原得到了5,10,15-三(3-氨基苯基)咔咯(b).测定了种两化合物在二氯甲烷中的紫外-可见光谱、荧光光谱,并借助红外、核磁共振和质谱等技术对化合物的结构进行了表征.发现化合物a和b的Soret带吸收分别位于418和416nm,Q吸收峰则分别位于576,614,646nm和572,614,646nm波长处;而化合物a和b的荧光发射光谱的最强峰分别位于674nm和671nm波长处.     

LaPO4:Eu3+的PEG2000辅助水热法制备及发光特性

采用水热法,以聚乙二醇2000(PEG2000)为添加剂,成功制备了铕掺杂的磷酸镧纳米颗粒。通过扫描电子显微镜(SEM)观察到所制得的纳米颗粒分散性较好,呈球形放射状结构。用X射线粉末衍射仪(XRD)对其结构进行了表征,实验表明:LaPO4属单斜晶系,独居石结构,700℃煅烧2 h基本晶化完全。研究了不同合成条件、煅烧时间、煅烧温度及不同铕含量对材料发光性质的影响,荧光光谱(FS)数据表明:最佳制备条件是pH等于9的条件下180℃反应14 h;随着煅烧温度的升高,激发峰及各个发射峰的强度都增大,850℃时,煅烧1 h发光强度最大,随着时间的延长发光强度反而减小;随着铕含量的增加,发光强度先增强后减弱,Eu3 的掺加量在4%(摩尔分数)时,纳米粒子的荧光强度最强,更高的掺杂浓度将导致荧光猝灭。     

一种蓝光发射材料的表征及发光性能研究

8-羟基喹啉铝类有机金属配合物作为一类重要的发光材料广受关注.文章合成并通过真空升华提纯得到了一种高纯度的8-羟基喹啉铝的衍生物-三(2-甲基-8-羟基喹啉)铝,通过红外光谱、核磁共振谱以及元素分析确定了三(2-甲基-8-羟基喹啉)铝的分子结构.通过热重和差示扫描量热分析研究了三(2-甲基-8-羟基喹啉)铝的热稳定性,试验结果表明:此衍生物的结晶转变温度可达158℃,分解温度为357℃;并进一步通过紫外可见吸收光谱和荧光光谱表征了材料的带隙以及能带结构.将吸收边的线性关系延伸到与能量轴相交所得禁带宽度2.85 eV,三(2-甲基-8-羟基喹啉)铝在365 nm紫外光的激发下,在乙醇溶液体系中的荧光发射峰在479 nm处,为蓝色荧光,荧光量子效率高,是一种蓝光发射的优选材料.     

橙汁饮品的荧光光谱特性及模式识别

应用FLS920型荧光光谱仪测得鲜榨橙汁、市售橙汁饮品(8种品牌)的三维荧光光谱,通过分析鲜榨橙汁与饮品中常见食品添加剂纯物质的荧光机理与特性,得到橙汁饮品中橙汁成分的最佳激发波长为470 nm,荧光峰值波长为526 nm,其荧光特征峰为470/526 nm,其余荧光峰的归属均为食品添加剂。同时,采用三维荧光光谱重心法与基于MCD估计的稳健马氏距离相结合的方法对市售橙汁饮品进行筛选与分类,分类效果良好。结果表明:将荧光光谱技术与光谱模式识别方法相结合,可为饮料类食品的鉴别提供帮助。     

油基钻井液条件下油层的NMR判识方法

油基钻井液具有润滑性好、抑制性强等特点,有利于井壁稳定和油气层保护,在非常规油气水平井及深井、超深井中广泛使用．但是,油基钻井液具有较强的荧光背景和全烃基值,岩屑难以洗出本色,地层油与钻井液的基础油融合,给油层的识别和评价带来了严重影响．为此,创新采用高分辨率低场核磁共振技术随钻监测钻井液含油率及含油性的变化．室内实验结果表明,油基钻井液不同于混油钻井液,后者属于水包油体系,钻遇油层后,在钻井液T₂谱上出现新峰;而前者属于油包水体系,钻遇油层后,在钻井液T₂谱上不出现新峰,但可通过含油性的变化识别重质油层,通过含油率的变化识别轻-中质油层,并在S903H井全油基钻井液及极端的地质条件下取得了较好的应用效果,证明了钻井液核磁共振是油基钻井液条件下一项有效的油层识别技术．     

基于荧光光谱技术对常用洗衣粉中表面活性剂含量的测定

十二烷基苯磺酸钠(Sodium Dodecyl Benzene Sulfonate,SDBS)是一种通用的阴离子表面活性剂,其洗涤性能优良,配伍性能好,可与其他无助剂以不同比例配比,且价格便宜,被广泛应用于洗衣粉中。应用FS920荧光光谱仪分析了不同浓度的十二烷基苯磺酸钠水溶液和不同品牌洗衣粉水溶液的荧光光谱特性,发现十二烷基苯磺酸钠溶液的荧光特征峰位于λ_(ex)/λ_(em)=315/350nm,洗衣粉水溶液的荧光特征峰位于λ_(ex)/λ_(em)=356/430nm,经分析是由于洗衣粉中添加了其他非离子表面活性剂、沸石等物质使特征峰发生红移。根据荧光强度与浓度的关系,采用径向基神经网络完成了水溶液中十二烷基苯磺酸钠含量的定量测试,同时通过采用荧光光谱技术和径向基神经网络相结合的检测方法分析了生活中常见的7个常用品牌洗衣粉中表面活性剂的含量。     

PAMAM 树枝状大分子的紫外及荧光性质研究

以乙二胺为核,通过迈克尔加成反应和酯胺解反应这两个重复的步骤,合成了0.5～5.0代PAM-AM树枝状大分子,使用氢核磁共振波谱(1 H NMR)、碳核磁共振波谱(13 C NMR)和质谱(MS)等证明了树枝状大分子的结构。同时对不同代数树枝状大分子的紫外及荧光性质进行了研究,发现整代树枝状大分子和半代树枝状大分子由于端基的不同,从而表现出不同的紫外吸收峰位,而紫外吸收强度与树枝状分子的分子骨架有密切的关系。虽然没有传统的荧光发射基团,但PAMAM树枝状分子却表现出特有的荧光现象,本文对PAMAM树枝状分子的荧光性质的影响因素进行了详细的研究。     

Novel Amphiphilic Comb-Like Polymers: Synthesis,Characterization, and Their Properties as Viscosifying and Filtration Additives for Drilling Fluids

Novel amphiphilic comb-like polymers (CPASA), used as viscosifying and filtration loss additives for low-solid water-based drilling fluids under high temperature and salinity conditions, were prepared from acrylamide, sodium 4-styrenesulfonate, and allyl polyethylene glycol ether with toluylene-end groups via inverse microemulsion polymerization. The chemical structure was characterized by Fourier transform infrared spectroscopy (FTIR) and hydrogen nuclear magnetic resonance (¹H-NMR). The thermal stability, aqueous solution properties, and drilling fluid properties were evaluated. Results showed that the comb-like polymers exhibited dramatic enhancement in their thermal- and salt-resistant properties because of the steric hindrance and intermolecular associations of the side-chains. The rheological properties, filtration properties, and negative Zeta potentials of both fresh-water drilling fluid and saturated salt-water drilling fluid were greatly improved by the addition of CPASA before and after thermal aging tests, which were ascribed to the steric hindrance of its comb-like conformation, the strong electrical double layer force of clay particles, and the stable mud network formed by CPASA and clay particles in drilling fluid.     

NMR response of non-reservoir fluids in sandstone and chalk.

Transverse (T2) NMR relaxation time at 2 MHz proton resonance frequency was measured on core plug samples from two different lithologies, sandstone and chalk, before and after exposure to selected drilling fluids. The results show that NMR signal response was significantly altered after displacing 50% of the original pore fluids, crude oil and water, by drilling fluid filtrate. Relaxation spectra of the rock samples invaded by water-based filtrate shift to significantly shorter T2-values. This shift yields an underestimation of the free-fluid volumes when selecting cut-off values of 33 ms and 100 ms for sandstone and chalk, respectively. In opposite, rock samples affected by oil-based filtrate respond with a signal indicating significantly larger free-fluid volumes than present before exposure. NMR-permeability calculated based on the Timur-Coates Free Fluid model altered in some cases by one order of magnitude.     

基于二维核磁共振弛豫谱的雷四段孔隙度计算方法

基于常规测井资料的体积模型和一维核磁共振（NMR）测井资料的固定截止值法,可以计算地层孔隙度,但是扩径段孔隙度计算结果偏大.本文通过川西海相雷四段岩心样品NMR实验和实测二维NMR测井资料,开展扩径段的T₂、T₁孔隙度计算方法研究.首先总结不同孔径流体在T₂谱和T₁谱上的响应特征,分析钻井液流体峰截止值的分布范围和影响因素,建立钻井液流体弛豫时间截止值的计算模型;然后根据未扩径段和扩径段的粘土束缚水弛豫时间截止值确定原则,确立变粘土束缚水弛豫时间截止值的有效孔隙度计算方法.多口井的应用效果表明,基于T₁谱的孔隙度计算结果精度更高、定量分析误差小,能有效解决扩径段孔隙度计算结果偏大的问题,满足储层评价的要求.     

川西气田白云岩储层二维核磁共振测井气水识别方法

川西气田雷口坡组四段白云岩储层具有良好的天然气勘探开发前景,但是储层分布具有较强的非均质性,利用常规测井和一维核磁共振测井方法判断储层流体性质存在多解性．通过分析川西雷四段白云岩储层地质特征与测井响应特征,开展岩心二维核磁共振实验,明确了实验室分析与测井过程中环境、参数等影响因素,建立了岩心分析结果的校正方法,明确了钻井液、束缚流体、可动水与天然气信号在二维核磁共振测井中谱分布区间,建立了基于T₂-T₁、T₁/T₂（R）的白云岩储层二维核磁共振测井气水识别图版．利用图版对川西雷四段储层流体性质开展评价,二维核磁共振测井解释结论得到了实钻测试结果的验证,该气水识别方法填补了常规测井、一维核磁共振测井在评价储层气水关系中的缺陷,可有效解决白云岩储层流体性质判别难题．     

Creating a collimated ultrasound beam in highly attenuating fluids

We have devised a method, based on a parametric array concept, to create a low-frequency (300-500 kHz) collimated ultrasound beam in fluids highly attenuating to sound. This collimated beam serves as the basis for designing an ultrasound visualization system that can be used in the oil exploration industry for down-hole imaging in drilling fluids. We present the results of two different approaches to generating a collimated beam in three types of highly attenuating drilling mud. In the first approach, the drilling mud itself was used as a nonlinear mixing medium to create a parametric array. However, the short absorption length in mud limits the mixing length and, consequently, the resulting beam is weak and broad. In the second improved approach, the beam generation process was confined to a separate “frequency mixing tube” that contained an acoustically non-linear, low attenuation medium (e.g., water) that allowed establishing a usable parametric array in the mixing tube. A low-frequency collimated beam was thus created prior to its propagation into the drilling fluid. Using the latter technique, the penetration depth of the low frequency ultrasound beam in the drilling fluid was significantly extended. We also present measurements of acoustic nonlinearity in various types of drilling mud.     

1H dynamic nuclear polarization in supercritical ethylene at 1.4 T

(1)H dynamic nuclear polarization (DNP) has been measured in supercritical ethylene in the pressure range 60-300 bar in an external field of 1.4 T. A single-cell sapphire tube was used as a high-pressure cell, and powdered 1,3-bisdiphenylene-2-phenyl allyl (BDPA) free radicals were added and distributed at the wall of the cell. At all pressures the dominant DNP mechanism was a positive Overhauser enhancement, caused by proton-electron contact interactions at the fluid/solid radical interface. The observed enhancements varied from 12 at 60 bar to 17 at 300 bar. Besides the Overhauser enhancement, small solid state and thermal mixing enhancements also were observed, indicating that part of the ethylene was adsorbed at the radical surface for a prolonged time. The impacts of the experimental conditions on the Overhauser enhancement factors are discussed, and enhancements of at least 40-60 are estimated when the EPR saturation factor and the leakage factor become maximal. These data indicate that DNP-enhanced NMR has the potential of extending the impact of NMR in research areas involving supercritical fluids.     

不同工质中汽泡周围电场特性研究

为探明外加电场作用下,不同工质对强化沸腾换热的影响,本文采用了FC-72、R11、R113和R123四种工质,定量研究了两相系统中汽泡周围电场分布特性,探讨了工质介电常数对汽泡的作用规律．结果表明:随着工质介电常数的增加,电场非均匀性增强,电场对汽泡的作用加剧．这为不同工质对EHD沸腾强化效果不同提供了理论依据．     

Analysis of Metabolites in Allantoic Fluid of Chicken Embryo by 900 MHz NMR Spectroscopy

900 MHz ¹H NMR (nuclear magnetic resonance) spectroscopy was used to analyze metabolites in allantoic fluid of the chicken embryo in the 9th incubation day without any chemical or physical sample separation. The result showed that superhigh spectral dispersion and sensitivity at 900 MHz are useful in directly analyzing a complex mixture, particularly in resolving the overlapped NMR resonances. In this study, we had assigned 61 metabolites and 26 chemical fragments in the allantoic fluid. The relative concentrations of the major metabolites were also measured. Among the assigned metabolites, some were detected by NMR in chicken embryo allantoic fluids for the first time. The biological functions of these compounds were briefly discussed. Authors' address: Maili Liu, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China     

浮升力和流动加速对超临界CO2管内流动传热影响

基于单相流体的概念,超临界流体的异常传热行为已经被研究很多年了,但是关于其流动传热机理仍没有统一的认识.本文通过理论分析和实验研究了超临界二氧化碳在竖直管内向上流动过程中,浮升力和流动加速效应对其流动结构和传热过程的影响.结果表明,没有确凿的实验证据表明超临界流体的异常传热行为是浮升力和流动加速直接导致的,存在的估计浮升力和流动加速效应准则均是在常物性流体的基础上,做了大量假设得出的,不同的研究者采用浮升力和流动加速准则分析超临界流体的传热恶化得出的结论不一致.最后,基于拟沸腾理论分析超临界流体的传热恶化过程,提出超临界沸腾数区分了超临界流体正常传热与恶化传热的转换边界,为超临界流体流动传热研究提供新思路,超临界沸腾数对建立用于不同技术的超临界流体动力循环的最佳运行条件具有重要意义.