用柠檬酸还原的Cr^3＋-HPAM胶态分散体冻胶性能研究

研究了柠檬酸与重铬酸钠的反应历程、生成螯合物的结构以及Cr^3 -HPAM胶态分散体冻胶的性能。在75℃下用柠檬酸将重铬酸钠中的Cr^6 还原为Cr^ 3 ，同时与Cr^3 发生螯合反应，生成柠檬酸铬螯合物。这种螯合物在一定条件下释放出Cr^3 ，它与HPAM交联形成胶态分散体冻胶。实验表明，柠檬酸铬-HPAM胶态分散体冻胶体系最长的成冻时间为40d，最大强度为0．036 MPa。用平行管岩心模型考察了冻胶的液流转向作用，调剖后高渗透层流量减小，液流转向低渗透层。     

钙离子对部分水解聚丙烯酰胺冻胶失水的作用机制研究

冻胶失水导致的体积收缩会缩短油田调剖堵水作业的有效期,因此冻胶失水问题需要引起足够的重视。考察了CaCl_2对部分水解聚丙烯酰胺/铬(HPAM/Cr)冻胶失水规律的影响,研究了CaCl_2对HPAM/Cr冻胶微观形貌、HPAM流体力学半径、黏度的影响;并通过红外光谱技术分析了CaCl_2对HPAM/Cr冻胶失水的作用机理。实验结果表明,高浓度CaCl_2会促进HPAM/Cr冻胶失水,而低浓度CaCl_2具有抑制HPAM/Cr冻胶失水的作用;冻胶容水孔洞减少是高浓度CaCl_2加剧HPAM/Cr冻胶失水的内在原因;HPAM流体力学半径越小,HPAM/Cr冻胶失水越严重,低浓度CaCl_2具有提高HPAM流体力学半径的作用;低浓度CaCl_2能够降低HPAM的黏度损耗速率;Ca~(2+)可与HPAM分子羧基中的C—O发生交联反应,该反应是低浓度CaCl_2能够提高HPAM流体力学半径、降低HPAM黏度损耗速率以及抑制HPAM/Cr冻胶失水的根本原因。明确了CaCl_2对冻胶失水的作用机理,可为今后研制抗盐高稳定性冻胶提供理论参考和支持。     

硫化氢对冻胶型堵剂的影响

研究了H2S对常规冻胶型堵剂成冻时间和冻胶强度的影响,这些冻胶型堵剂包括交联聚丙烯酰胺形成的铬冻胶和酚醛树脂冻胶.探讨了H2S对冻胶型堵剂影响的作用机理.结果表明:H2S对无机铬交联体系的影响较大,而对有机铬交联体系和酚醛树脂交联体系的影响相对较小;对于无机铬交联体系,H2S能迅速将Cr6+还原为Cr3+,提高交联HPAM的速度,而当H2S含量偏高时,被还原出的Cr3+会与过量的H2S生成Cr2S3沉淀,不能形成整体冻胶;对有机铬和酚醛树脂交联体系的影响主要体现在pH值的变化上.当选择冻胶型堵剂应用于含H2S的油气藏时,最好选用酚醛树脂冻胶.     

微纳尺度冻胶分散体杨氏模量对封堵性能影响

致密/页岩油气长期压裂开发下优势窜流通道发育，冻胶分散体在流道调控扩大波及方面具有很好的应用效果。冻胶分散体机械强度与其宏观封堵性能间应有密切关系，然而，目前的冻胶分散体机械强度缺乏有效表征手段。以铬冻胶分散体为例，通过原子力显微镜直接测量了微纳尺度铬冻胶分散体杨氏模量，并通过对其宏观封堵性能进行评价，从而建立了二者间映射关系。研究表明，控制聚合物质量分数为0.3%，SD-107质量分数由0.4%增大到0.7%，本体冻胶强度随之增大，相应冻胶分散体杨氏模量也随之增加。当杨氏模量自159 Pa上升至633 Pa时，封堵率由93.23%上升至98.08%。通过调控微纳尺度冻胶分散体杨氏模量研究其封堵性能差异，为致密/页岩油气储层高效开发提供基础理论指导。     

缓交联氨基树脂冻胶成胶性能

深部调剖是高含水油田控水稳油的重要措施。低油价下深部调剖需要成胶时间长、成胶后强度高的冻胶堵剂。以低质量分数的部分水解聚丙烯酰胺(HPAM)为成胶液,以氨基树脂为交联剂,研究了氨基树脂冻胶的成胶规律及其使用条件。研究结果表明,在乙酸催化下,氨基树脂可和低质量分数HPAM交联形成冻胶,该冻胶可以在70℃、盐含量为10 174 mg·L~(-1)以下地层使用。成胶时间大于3 d,冻胶强度可达到G级以上,冻胶90 d脱水率小于10%,适合深部调剖。     

壳聚糖螯合铬(Ⅵ)的稳定常数测定及螯合效果分析

为了考察壳聚糖（CTS）对重金属离子铬(VI)的螯合性能,利用紫外分光光度法对壳聚糖螯合铬(VI)的机理进行了研究,测定了不同c(Cr6+)/c(-NH3+)浓度比下壳聚糖-铬(Ⅵ)螯合物的紫外吸收光谱,确定了螯合物的配位比并计算了稳定常数。结果表明：壳聚糖对铬(VI)具有螯合作用,在不同壳聚糖氨根配体浓度下,当c(Cr6+)/c(-NH3+)≥0.5时,螯合反应达到平衡;壳聚糖中主要配体-NH2基团与铬(VI)按物质的量比2:1形成螯合物,壳聚糖铬(VI)螯合物的稳定常数为1.212×108。通过实验考察了壳聚糖用量、体系pH值对壳聚糖螯合铬(Ⅵ)离子效果的影响。结果表明：壳聚糖用量为0.15 g·L-1,反应酸碱度为pH=4的弱酸环境时,铬(VI)离子去除率可达到87.5%。     

温度和盐浓度对Cr~(3+)与HPAM交联反应速率及冻胶脱水率的影响

针对过交联造成的冻胶堵剂脱水问题,通过实验建立了一种可以具体表征交联反应过程的方法,即采用分光光度法测定Cr~(3+)浓度以表征Cr~(3+)交联剂的反应速率。考察了交联反应过程中交联剂Cr~(3+)的反应量、冻胶脱水率的变化情况,研究了温度和盐浓度对Cr~(3+)与HPAM交联反应速率及冻胶脱水率的影响,并对交联速率与冻胶脱水的相互关系进行了分析。研究结果表明,温度升高后,Cr和聚合物羧基之间的反应速率加快,交联中间体——Cr多核羟基桥离子的形成速率也会加快;温度越高,Cr多核羟基桥离子的流体力学直径增大速度越快,从而使得Cr的交联反应速率越快。而增大无机盐浓度,有利于Cr多核羟基桥离子的形成,其流体力学直径达到最大值的时间显著缩短。因此,在温度和无机盐的影响下,交联反应过程中冻胶易出现交联速率过快的问题,交联过度会增加交联体系的密度,导致交联体系的保水能力降低,从而使冻胶脱水。本研究对探索抑制冻胶体系脱水的方法具有指导意义。     

清水配置冻胶在盐水中稳定性的变化研究

本文以水溶性酚醛树脂为交联剂,以纳米颗粒为稳定剂,以HPAM以及不同AMPS含量的聚合物为成胶剂,在低盐含量的模拟注入水中制备了稳定的冻胶。研究发现,相同交联剂和聚合物用量下,AM-AMPS共聚物成胶时间比HPAM长,但成胶后强度高。评价了制备的冻胶在不同盐含量模拟水中的脱水情况,结果表明,当模拟水盐含量为10000mg/L、30000mg/L时,冻胶会吸水膨胀、强度降低;但当模拟水盐含量高于50000mg/L时,冻胶则脱水,冻胶强度提高。模拟水盐含量越高,脱水幅度越大。提高冻胶中纳米颗粒的含量或用AMPS含量高的共聚物做成胶剂,可明显降低冻胶在高盐含量中的脱水幅度。研究结果对红河油田裂缝封堵剂的开发有指导意义。     

胶态分散凝胶(CDG)成胶规律及封堵能力研究

首先研究了HPAM的交联影响因素以及胶态分散凝胶的堵水调剖渗流特征.与同浓度的聚合物(HPAM)相比,胶态分散凝胶的粘度降低,下降幅度与聚合物浓度、水解度、分子量有关;在所选用的交联比、分子量、水解度、浓度条件下,均可生成胶态分散凝胶,并且聚合物浓度越大,生成胶态分散凝胶后其粘度的下降幅度越大.聚合物分子量对胶团粒度的影响较大;胶态分散凝胶具有较好的注入能力,可进行深部调剖,提高水驱的波及体积.     

多孔介质剪切下铬冻胶体系成胶行为研究

采用安瓿瓶和填砂管考察了铬冻胶体系的静态成胶和动态成胶过程.结果表明:同一配方下铬冻胶在多孔介质中动态成胶的初始成胶时间是其在多孔介质中静态成胶的初始成胶时间的1～3倍,最终成胶时间是其在多孔介质中静态成胶时间的1～3.5倍.铬冻胶在多孔介质中静态成胶的初始成胶时间是其在安瓿瓶内静态成胶的初始成胶时间的1～2倍,最终成胶时间是其在安瓿瓶内静态成胶时间的3～5倍.随着剪切速率的增大,铬冻胶体系受到的剪切作用增强,其初始成胶时间和最终成胶时间均延长,成胶后的封堵能力降低.随着聚合物浓度和交联剂浓度的增大,铬冻胶的初始成胶时间和最终成胶时间均延长,成胶后的强度增大.聚合物分子的吸附和捕集作用不是引起压力增大的主要原因,引起压力变化的主要因素是铬冻胶在多孔介质中的成胶.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to