利用测井资料预测欠压实超压层方法研究

以欠压实作用产生的超压层为研究对象,分析了声波测井、密度测井、中子测井和电阻率测井在欠压实超压层中的响应特征,研究认为:欠压实超压地层的声波时差、中子测井响应值较正常压实情况下要大,而密度、电阻率较正常压实情况下小.其中,声波时差、电阻率的这种现象最为明显.通过对常规测井在欠压实超压层中的测井响应特征分析,提出了利用综合压实曲线判别法来识别欠压实超压层,通过对某区块井的实例分析,验证了该方法的可靠性.     

碳酸盐岩剖面地层孔隙压力计算方法研究

从等效深度法的基本原理出发,重点讨论了碳酸盐岩剖面地层正常压实趋势线的构建问题,并利用所构建的正常压实趋势方程对川东飞仙关组碳酸盐岩剖面裂缝-孔隙型储层的地层孔隙压力进行了预测。结果表明,等效深度法对碳酸盐岩剖面的地层孔隙压力预测同样也有一定的实用性。     

南海流花海域钻井安全钻井液密度窗口计算分析

为了准确确定安全钻井液密度窗口,并维持钻井过程的井壁稳定成为制约南海海上油气开发目前所面临的重要问题。针对该问题,基于流花海域LH20-2油田各已开发井的声波时差及其他测井数据,利用Eaton法对该构造的孔隙压力分布规律进行了预测。此外,对该地区地层的破裂压力和坍塌压力随井斜角和方位角的分布规律进行了定量分析,最终得到了各井段安全钻井液密度窗口。结果表明,油田孔隙压力分布范围在0. 98～1. 05 g/cm~3,处于正常压力系统内。并且得出,拟开发井直井段和水平段安全钻井液密度窗口依次是1. 07～1. 10 g/cm~3和1. 22～1. 25 g/cm~3。此研究可以为南海LH20-2油田拟开发井钻井液设计提供依据和参考。     

利用测井资料进行孔隙压力预测和井壁稳定性分析

本文利用测井资料,采用等效深度法求得了加蓬区块3口井的地层孔隙压力, 利用常规测井资料计算岩石力学特征参数、进行地应力分析,在此基础上计算井壁破裂压力、坍塌压力,进行井眼稳定性评价,得到了该工区地层的钻井液密度安全窗口.从力学角度出发,计算地层孔隙压力、进行井眼稳定性评价,可以为钻井工程设计钻井液密度提供重要参考依据,具有较大的实用价值.     

锦州25-1油田井壁稳定问题

 锦州25-1油田沙河街组地层井壁失稳严重,为解决该油田的井壁失稳问题,对该油田的泥页岩矿物组分进行了分析,开展了泥页岩的力学及水化特性实验,分析了锦州25-1油田沙河街组泥页岩的岩石力学特性和井壁失稳机制.研究发现,沙河街组地层层理性泥页岩和水敏性泥页岩共同发育;层理性泥页岩具有显著的各向异性,易发生沿层理面的剪切滑移,造成井壁失稳;水敏性泥页岩在钻井液作用下会发生水化膨胀,导致井周地层的力学性质和应力状态发生变化,表现为坍塌压力随井眼钻开时间的改变而改变;两种地层相互影响造成油田复杂事故频发.结合室内实验结果,建立了合理钻井液密度的确定方法,研究了锦州25-1油田层理性泥页岩坍塌压力随井眼轨迹的分布规律和水敏性泥页岩的水化坍塌周期,给出了保证安全钻进的工程对策,该油田的井壁失稳问题必须在优化井眼轨迹和选择合理钻井液密度基础上,并增强钻井液的封堵性和抑制性才能解决.     

莺歌海盆地泥岩稳定压实带成因及石油地质意义

莺歌海盆地为快速沉积、沉降的伸展-转换盆地,泥岩压实为常见的指数压实模式,同时,泥岩压实曲线具有典型的稳定压实带:即明显偏离正常压实趋势线,其声波时差值基本保持在约300μs/m,厚度一般为700~1000m,岩性主要以莺-黄组深海—半深海相泥岩为主,为孔隙度基本稳定段,但其测试地层压力却为正常静水压力.分析了泥岩声波稳定压实带的层位、岩性组合、热演化剖面、气测烃及与黏土矿物转化带的关系,认为其形成并非只与黏土矿物转化有关,中央凹陷带底辟区的泥岩稳定压实带是黏土矿物转化和流体排放共同作用形成的,非底辟区则是局部流体排放造成的结果.稳定压实带普遍位于超压带顶面上部,反映出稳定压实带实际上为超压系统的封闭层,强烈底辟区稳定压实带的消失则可能表明深部超压流体向浅部的排放,油气则可能主要集中在浅部层位.因此,正确识别稳定压实带对于准确预测欠压实引起的偏离正常压实趋势线的超压及油气聚集分布具有重要的理论和实践意义.     

伊朗Y油田孔隙型灰岩地层压力检测方法研究

灰岩地层纵波速度对地层压力变化敏感性较低,若采用传统针对砂泥岩地层的模型进行孔隙压力计算可能导致较大计算误差。伊朗Y油田上部地层主要为砂泥岩夹孔隙型灰岩地层,中下部为大段孔隙型灰岩地层。针对该油田孔隙型灰岩地层岩性、异常高压形成机制、地球物理响应特点,形成了一套孔隙型灰岩地层压力综合检测方法。对于中部具有泥岩夹层的灰岩地层,优选传统基于泥页岩沉积压实规律的计算方法;对于无法提取泥岩点的大段孔隙型灰岩地层,采用多元速度模型和有效应力定理进行检测。方法在Y油田20口井得到应用,检测精度达90%以上,为井身结构和钻井参数优化提供了重要地质参数。     

基于数字岩心的泥浆侵入数值模拟及微观机理

石油钻井中由于钻井液压力略大于地层压力,使得钻井泥浆侵入到原始地层中,改变地层的电阻率,进而影响电阻率测井的准确性。以岩心CT扫描得到的数字岩心模型为基础,利用格子玻尔兹曼方法来模拟泥浆侵入的过程,结合有限元方法计算泥浆侵入过程中岩心电学特性参数的变化,并结合岩心孔隙结构参数,从微观尺度上认识泥浆侵入过程,从而系统地分析泥浆侵入的微观机理。孔隙微观结构参数中,渗透率、孔隙连通性及孔喉半径对泥浆侵入和电阻率影响显著,在实际测井解释中,有必要针对不同渗透率的岩心建立相应的电阻率校正模型。     

泥岩压实研究中有机质导致声波时差异常的定量校正方法

高丰度有机质导致的声波时差异常高值不能客观反映地层孔隙度的变化,定量研究有机质对压实曲线的影响才能减小压实研究结果的不确定性。从泥岩压实研究的原理出发,构建考虑干酪根的岩石等效体积模型,提出有机质引起声波时差增量的校正公式;以鄂尔多斯盆地南部镇泾地区为例,讨论压实曲线有机质校正方法的实用性及可靠性。结果表明:烃源岩层段高丰度有机质往往造成压实规律的较大误差,压实研究中应当消除有机质对声波时差的影响;镇泾地区泥岩压实曲线经过校正后,正常压实趋势线斜率减小约30%~55%;长7段底部页岩欠压实幅度显著降低,最大埋深时期的剩余压力约为3~5 MPa,相比于校正前降低5~8 MPa,反映出以往研究可能过高地估计了长7段古超压的幅度;利用校正后声波时差计算的泥岩孔隙度与实测孔隙度吻合性较好,且计算的流体压力与数值模拟结果一致,证实提出的定量校正方法能够有效地消除研究区有机质造成的声波时差异常,可作为鄂尔多斯盆地及其他地区压实研究的借鉴。     

实验分析泥岩水化膨胀应力与力学参数之间的关系

在钻井的过程中,泥页岩地层一旦与水基钻井液接触后,便会发生水化膨胀作用,在地层压力和上覆岩层压力的约束下产生膨胀应力,岩石强度降低,井壁稳定性下降。因此,研究水化膨胀作用与力学参数之间的关系是研究泥岩井壁稳定的关键内容之一。基于泥页岩的水化作用机理,通过室内实验分析了水基钻井液中的离子类型及其浓度对水化膨胀应力的影响,并且测量了岩样水化后的力学参数。实验结果表明泥岩水化膨胀应力与离子类型和浓度有关;水化后泥岩的含水量越大,产生的线膨胀应力越大,力学参数越小;线膨胀应力与泥岩水化后的力学参数之间具有较好的指数递减关系。     

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