二维自组织介质中地震波的传播特性

The topic of this study is simulation in the two dimensional self-organized media. The study in complexity of the earth plays an important role in structures, sources and energy seismic detection. And it mainly focuses on vertical or horizontal heterogeneous, anisotropic and linear media. Based on 2D self-organized velocity model and four-order finite-difference method, we simulate different types self-organized media and the same type mode with various parameters such as horizontal relative length, vertical relative length, variations, and velocity background gradient. Also we analyze the seismograms with complexity methods with instant information including amplitude, energy and frequency. The results can be summarized as the fallows: (1) The waveforms fluctuate with the velocity variations; (2) Different type self-organized media bring different effects on the amplitudes, energy and waveforms; (3) Different parameters also produce various influences to seismograms. (4) The layer contains their self-organized features, from which we can investigate the quality of the earth.

地震波模拟：非规则网格离散的数值解法、吸收边界及其实际应用

This dissertation presents a series of irregular-grid based numerical technique for modeling seismic wave propagation in heterogeneous media. The study involves the generation of the irregular numerical mesh corresponding to the irregular grid scheme, the discretized version of motion equations under the unstructured mesh, and irregular-grid absorbing boundary conditions. The resulting numerical technique has been used in generating the synthetic data sets on the realistic complex geologic models that can examine the migration schemes. The motion equation discretization and modeling are based on Grid Method. The key idea is to use the integral equilibrium principle to replace the operator at each grid in Finite Difference scheme and variational formulation in Finite Element Method. The irregular grids of complex geologic model is generated by the Paving Method, which allow varying grid spacing according to meshing constraints. The grids have great quality at domain boundaries and contain equal quantities of nodes at interfaces, which avoids the interpolation of parameters and variables. The irregular grid absorbing boundary conditions is developed by extending the Perfectly Matched Layer method to the rotated local coordinates. The splitted PML equations of the first-order system is derived by using integral equilibrium principle. The proposed scheme can build PML boundary of arbitrary geometry in the computational domain, avoiding the special treatment at corners in a standard PML method and saving considerable memory and computation cost. The numerical implementation demonstrates the desired qualities of irregular grid based modeling technique. In particular, (1) smaller memory requirements and computational time are needed by changing the grid spacing according to local velocity; (2) Arbitrary surfaces and interface topographies are described accurately, thus removing the artificial reflection resulting from the stair approximation of the curved or dipping interfaces; (3) computational domain is significantly reduced by flexibly building the curved artificial boundaries using the irregular-grid absorbing boundary conditions. The proposed irregular grid approach is apply to reverse time migration as the extrapolation algorithm. It can discretize the smoothed velocity model by irregular grid of variable scale, which contributes to reduce the computation cost. The topography. It can also handle data set of arbitrary topography and no field correction is needed.

波动方程模拟与偏移的实用化方法研究

Along with the widespread and in-depth applications in petroleum prospecting and development, the seismic modeling and migration technologies are proposed with a higher requirement by oil industrial, and the related practical demand is getting more and more urgent. Based on theories of modeling and migration methods for wave equation, both related with velocity model, I thoroughly research and develop some methods for the goal of highly effective and practical in this dissertation. In the first part, this dissertation probes into the layout designing by wave equations modeling, focusing on the target-oriented layout designing method guided by wave equation modeling in complicated structure areas. It is implemented by using the fourth order staggered grid finite difference (FD) method in velocity-stress 2D acoustic wave equations plus perfectly matched layer (PML) absorbing boundary condition. To design target-oriented layout: (a) match the synthetic record on the surface with events of subsurface structures by analyzing the snapshots of theoretical model; (b) determine the shot-gather distance by tracking the events of target areas and measuring the receiving range when it reaches the surface; (c) restrict the range of valid shot-gather distance by drawing seismic windows in single shot records; (d) choose the best trace distance by comparing the resolution of prospecting targets from the simulated records with different trace distance. Eventually, we obtained the observation system parameters, which achieve the design requirements. In the second part, this dissertation presents the practical method to improve the 3D Fourier Finite Difference (FFD) migration, and carefully analyzes all the factors which influence 3D FFD migration’s efficiency. In which, one of the most important parameters of migration is the extrapolating step. This dissertation presents an efficient 3D FFD migration algorithm, which use FFD propagator to extrapolate wavefields over big layers, and use Born-Kirchhoff interpolator to image wavefields over small layers between the big ones. Finally, I show the effectiveness of this hybrid migration method by comparing migration results from 3D SEG/EAGE model with different methods.

喜马拉雅西构造结区岩石圈演化三维有限元动力学数值模拟

The past three decades have seen numerous attempts to numerically model stress and strain patterns in the lithosphere of the Earth on both global and regional scales. This efforts have been indispensable in identifying the features we need to include in our endeavour to develop better models of our planet’s lithosphere and they have also raised our awareness for the many unresolved issue in the deep geodynamical issues that need to be addressed in the future. Nonetheless, in most models, the lithosphere is treated as a single layer with depth-averaged properties, and as the same distribution in the stress and strain fields, and as deforming under plane strain. All these above make a great hander for its reality and degree of recognition. As the beginning in this paper, some principal numerical models and results on the evolution of Tibetan plateau are reviewed and analyzed. Then, the geological and geophysical expedition on the Western Himalayan Syntaxis is briefly reviewed. Furthermore, we analysis the feature in deep geophysical field studies in this area and adjacent regions. Because, for most continents, stress models driven by plate boundary forces have successfully reproduced the main characteristics of the stress and strain field, we present a set of three-dimensional models of lithosphere system for a simplified geometry of the Western Himalayan Syntaxis area and its adjacent regions, where we try to match the first-order characteristics of the stress and strain fields of lithosphere since 10 Ma, and deformation and geodynamical evolution process in former 2Ma. Of course, the kinematic boundary conditions of the stress models driven by plate boundary forces were applied. The rheology plays a significant role in the lithospheric tectonics, which lead to different rheological parameters were used in different works although the have the same constitutive equations in models. So, in this paper we do not aim to produce all characteristics of the Western Himalayan Syntaxis areas’ stress and strain fields by the choices of various parameters, but rather the dynamic response between various rheological parameters and stress and strain fields. We have chosen to concentrate on the importance of rheology and lateral strength variations for lithospheric stress and strain patterns and use our findings to build a model of the Western Himalayan Syntaxis areas. In doing so, we want to go beyond purely elastic models or purely viscoelastic models. Compared the results of the crust viscosity in the Western Himalayan Syntaxis areas, we believed that, when various viscoelastic models are adopted, the selection of the coefficient of viscosity in the Western Syntaxis area has important influence on the its uplifts and evolutions. A wider uplift ranges and gently elevation was observed at the same time when a lower viscosity was used in our models, and vice versa. Data of stress magnitudes are not available, but it is clear that the stress levels must be at or below the failure threshold of rock under compression. Under these criteria, the calculation results show that the viscosity in the Western Syntaxis area should be smaller than 1023Pa.s When elastic model is adopted in relatively rigid Tarim basin, obvious changes are induced to the stress and strain fields of the whole Western Syntaxis area. We found that rigid block of lithosphere reduced stress levels within its interior and that, at the edges of such regions, stress orientation can change. Furthermore there is no evidence that such rigid regions act as stress barriers in that they shield areas in opposite sides of the structure from the influence of one another. In our models, the upper crustal material of the Western Syntaxis area does not turns to move westward. Whereas, because of the stress and strain fields have been decoupling at the interior of the lithosphere, we can get the results that the deep material must not move westward.

太阳活动变化对中低纬电离层的影响

With the variations of solar activity, solar EUV and X-ray radiations change over different timescales (e.g., from solar cycle variation to solar flare burst). Since solar EUV and X-ray radiations are the primary energy sources for the ionosphere, theirs variations undoubtedly produce significant and complicated effects on the ionosphere. So the variations of solar activity significantly affect the ionosphere. It is essential for both ionospheric theory and applications to study solar activity effects on the ionosphere. The study about solar activity variations of the ionosphere is an important part of the ionospheric climatology. It can enhance the understanding for the basic processes in the ionosphere, ionospheric structure and its change, ionosphere/thermosphere coupling, and so on. As for applications, people need sufficient knowledges about solar activity variations of the ionosphere in order to improve ionospheric models so that more accurate forecast for the ionospheric environments can be made. Presently, the whole image about the modalities of ionospheric solar activity variations is still unknown, and related mechanisms still cannot be well understood. This paper is about the effects of the 11-year change in solar activity to the low- and mid-latitude ionosphere. We use multi-type ionospheric observations and model to investigate solar activity effects on the electron density and ionospheric spatial structure, and we focus on discussing some related mechanisms. The main works are as follows: Firstly, solar activity variations of ionospheric peak electron density (NmF2) around 1400 LT were investigated using ionosonde observations in the 120°E sector. The result shows that the variation trend of NmF2 with F107 depends on latitudes and seasons. There is obvious saturation trend in low latitudes in all seasons; while in middle latitudes, NmF2 increases linearly with F107 in winter but saturates with F107 at higher solar activity levels in the other seasons. We calculated the photochemical equilibrium electron density to discuss the effects induced by the changes of neutral atmosphere and dynamics processes on the solar activity variations of NmF2. We found that: (1) Seasonal variation of neutral atmosphere plays an important role in the seasonal difference of the solar activity variations of NmF2 in middle latitudes. (2) Less [O]/[N2] and higher neutral temperature are important for the saturation effect in summer, and the increase of vibrational excited N2 is also important for the saturation effect. (3) Dynamics processes can significantly weaken the increase of NmF2 when solar activity enhances, which is also a necessary factor for the saturation effect. Secondly, solar activity variations of nighttime NmF2 were investigated using ionosonde observations in the 120°E sector. The result shows that the variation trends of NmF2 with F107 in nighttime are different from that in daytime in some cases, and the nighttime variation trends depend on seasons. There is linear increase trend in equinox nighttime, and saturation trend in summer nighttime, while the increase rate of NmF2 with F107 increases when solar activity enhances in winter nighttime (we term it with “amplification trend”). We discussed the possible mechanisms which affect the solar activity variations of nighttime NmF2. The primary conclusions are as follows: (1) In the equatorial ionization anomaly (EIA) crest region, the plasma influx induced by the pre-reversal enhancement (PRE) results in the change of the variation trend between NmF2 and F107 from “saturation” to “linear” after sunset in equinoxes and winter; while the recombination process at the F2-peak is the primary factor that affects the variation trend of NmF2 with F107 in middle latitudes. (2) The recombination coefficient at the F2-peak height reaches its maximum at moderate solar activity level in winter nighttime, which induces NmF2 attenuates more quickly at moderate solar activity level. This is the main reason for the amplification trend. (3) The change of the recombination process at the F2-peak with solar activity depends on the increases of neutral parameters (temperature, density et al.) and the F2-peak height (hmF2). The seasonal differences in the changes of neutral atmosphere and hmF2 with solar activity are the primary reasons for the seasonal difference in the variation trend of nighttime NmF2 with F107. Finally, we investigated the solar activity dependence of the topside ionosphere in low latitudes using ROCSAT-1 satellite (at 600 km altitude) observations. The primary results and conclusions are as follows: (1) Latitudinal distribution of the plasma density is local time, seasonal, and solar activity dependent. In daytime, there is a plasma density peak at the dip equator. The peak is obviously enhanced at high solar activity level, and the strength of the peak strongly depends on seasons. While at sunset, two profound plasma density peaks (double-peak structure) are found in solar maximum equinox months. (2) Local time dependence of the latitudinal distribution is due to the local time variation of the equatorial dynamics processes. Double-peak structure is attributed to the fountain effect induced by strong PRE. Daytime peak enhances with solar activity since the plasma density increases with solar activity more strongly at the dip equator due to the equatorial vertical drift, and its seasonal dependence is mainly due to the seasonal variations of neutral density and the equatorial vertical drift. In the sunset sector, seasonal and solar activity dependences of the latitudinal distribution are related to the seasonal and solar activity variations of PRE. (3) The variation trend of the plasma density with solar activity shows local time, seasonal, and latitudinal differences. That is different from the changeless amplification trend at the DMSP altitude (840 km). Profound saturation effect is found in the dip equator region at equinox sunset. This saturation effect in the topside ionosphere is realated to the increase of PRE with solar activity. Solar activity variation trend of the topside plasma density was discussed quantitatively by Chapman-α function. The result shows that the effect induced by the change of the scale height is dominant at high altitudes; while the variation trend of ROCSAT-1 plasma density with solar activity is suggested to be related to the changes of the peak height, the scale height, and the peak electron density with solar activity.

滑坡型泥石流转化机理研究—以四川省达县青宁乡滑坡为例

Slide-debris flow is debris flow which is transformed from landslide consecutively in a short time, it comprises of two phases: First, Landslide starts to slide; Second, landslide changes to debris flow. Slide-debris flow which brings great property and life loss happens frequently at home and abroad. In order to forecast the happening possibility and scope of slide-debris flow, transfromation mechanism of Slide-debris flow must be studied. Research on transformation mechanism of slide-debris flow is intersectant science of landslide kinetics and debris flow starting theory, It is a fringe problem as well as front problem of geological hazard. This paper takes Qingning slide-debris flow in Da County, Sichuan Province for example and has studied the mechanism of its instability and transfromation into debris flow through indoor test (including usual soil test and ring shear test) and digital modeling method.The research gets the following conclusions. Qingning Landslide took place mainly because of confined water head arising from rainfall infiltration. Before Landslide occurring, it rained continuously for 22 days, accumulated precipitation arrived at 521.6mm.Investigation shows that strata of Qingning Landslide contains quaternary loose accumulation, slip soil and highly weathered bedrock, which is a good condition for formation of confined water in the slope. Further more, groundwater seepage in the slope body and corresponding slope safety factor before landslide occurring have been computed through finite element method. The result shows that because of infiltration of rainfall, confined water head in the slope arose sharply, accordingly, the safety factor of the slope declined quickly. The result also shows that force put on the slide body by the rock mass detached from Dazhaiyan mountain was the direct factor for landslide occurring. Qingning slide-debris transformation mode has been summarized, the process the landslide changed into debris flow is divided into three phases in the prospective of macroscopic geological condition: landslide occurring, transformation and debris flow. Landslide occurring phase is from slope’ local creeping slide to Landslide occurring; transformation phase contains slide body sliding on the slide bed after slide occurring and sliding on the slope after shearing opening; debris flow phase is that slide body breaks up completely and flows downward into the ditches. The transformation mechanism of Qingning slide-debris flow has been studied through indoor ring shear test of slip soil. The result shows that transformation mechanism contains two points: first, during slide body sliding on the slide bed and slope after shearing opening, shearing shrinkage, grain crushing and grain layering brought about declining of its volume and produced excess pore water pressure, and because producing velocity of excess pore water pressure is much greater than its dissipating velocity, shear strength of slide body decreased sharply because of accumulated pore water pressure. Second, grains crushing and grains layering during slide body sliding brought about thick liquefied layer at the bottom of the slidebody, liquefied layer contained high water content and its shear strength was very low, its thickness increased as the sliding displacement increasing. Liquefied layer makes slide body sliding fast and easily break down to debris flow. Excess pore water pressure and liquefied layer made shear strength of slidebody became very low, furthermore, water in the pit of slope joining in the slidebody was also a facter that made slidebody accelerate the transformation. Influence of slide body thickness and fine grains content to transformation of slide-debris flow has been studied through ring shear test. The result reaches two conclusions. First, thickness of slide body affects transformation of slide-debris flow by two ways, porewater pressure and effect of “soft base” increases as thickness of slide body increasing.so the thicker slide body is ,the easier transformation is. Second, actual dissipating velocity of porewater pressure should be considered when studying the influence of fine grains content to tranformation of slide-debris flow. There should be a critical content of fine grains which makes the difference of producing and dissipating velocity of water pore pressre greatest, this value is the best for slide-debris transformation. The whole process of slide-debris flow transformation is reproduced through discrete element method. Transformation mechanism of slide-debris flow is studied through monitoring various parameters including pore water pressure, grain crushing and grain layering in the slide body during the transformation. The result confirms and supplements the transformation mechanism of slide-debris flow got from ring shear test well.

孤东油田馆陶组河流相储层流动单元模型与剩余油分布规律研究

Since C.L. Hearn presented the concept of flow unit in 1984, its generation mechanisms and controlling factors have been studied in many aspects using different methods by researchers. There are some basic methods to do the research, and there are several concepts and classification standards about flow unit. Based on previous achievements and using methodologies from sedimentary geology, geophysics, seismic stratigraphy, and reservoir engineering, the author systemically studies the factors controlling flow unit, puts forward a series of methods for recognition, classification and evaluation of flow unit. The results obtained in this paper have important significance not only for understanding the flow unit, but also for revealing the distribution of remaining oil. As a case, this paper deals with the reservoir rocks in Guantao Group of Gudong Oilfield. Zhanhua Sag, Jiyang Depression in Bohaiwan Basin. Based on the study of stratigraphic, depositional and structural characteristics, the author establishes reservoir geological models, reveals the geological characteristics of oil-bearing reservoir of fluvial facies, points out the factors controlling flow unit and geological parameters for classification of flow unit. and summarizes methods and technologies for flow unit study when geological, well-logging and mathematical methods are used. It is the first attempt in literatures to evaluate reservoir by well-logging data constrained by geological conditions, then a well-logging evaluation model can be built. This kind of model is more precise than ever for calculating physical parameters in flow unit. In a well bore, there are six methods to recognize a flow unit. Among them, the activity function and intra-layer difference methods are the most effective. Along a section, the composition type of flow unit can be located according amplitude and impedance on seismic section. Slice method and other methods are used to distinguish flow unit. In order to reveal the distribution laws of flow unit in space, the author create a new method, named combination and composition of flow unit. Based on microscopic pore structure research, the classification methods of flow unit are developed. There are three types of flow unit in the reservoir of fluvial facies. They have their own lithology, petrophysics and pore structure character. Using judgement method, standard functions are built to determine the class of flow unit of fluvial facies. Combining reservoir engineering methods, the distribution laws of remaining oil in different types, or in different part of a flow unit are studied. It is evident that the remaining oil is controlled by the type of flow unit. The author reveals the relationship between flow unit and remaining oil distribution, builds the flowing models, predicts the variation of reservoir parameters in space, put forward different methods developing remaining oil in different flow unit. Especially, based on the results obtained in this paper, some suggestions for the adjustment of the developing flow units have been applied in Districts No.4 and No.7, and good results have been yielded. So, the results of this paper can guide oil field development. They are useful and significant for developing the remaining oil and enhancing the oil recovery efficiency.

三维油藏数值模拟正反演算法研究

The dynamic prediction of complex reservoir development is one of the important research contents of dynamic analysis of oil and gas development. With the increase development of time, the permeabilities and porosities of reservoirs and the permeability of block reservoir at its boundaries are dynamically changing. How to track the dynamic change of permeability and porosity and make certain the permeability of block reservoir at its boundary is an important practical problem. To study developing dynamic prediction of complex reservoir, the key problem of research of dynamic prediction of complex reservoir development is realizing inversion of permeability and porosity. To realize the inversion, first of all, the fast forward and inverse method of 3-dimension reservoir simulation must be studied. Although the inversion has been widely applied to exploration and logging, it has not been applied to3-dimension reservoir simulation. Therefore, the study of fast forward and inverse method of 3-dimension reservoir simulation is a cutting-edge problem, takes on important realistic signification and application value. In this dissertation, 2-dimension and 3-dimension fluid equations in porous media are discretized by finite difference, obtaining finite difference equations to meet the inner boundary conditions by Peaceman's equations, giving successive over relaxation iteration of 3-dimension fluid equations in porous media and the dimensional analysis. Several equation-solving methods are compared in common use, analyzing its convergence and convergence rate. The alternating direction implicit procedure of 2-dimension has been turned into successive over relaxation iteration of alternating direction implicit procedure of 3-dimension fluid equations in porous media, which possesses the virtues of fast computing speed, needing small memory of computer, good adaptability for heterogeneous media and fast convergence rate. The geological model of channel-sandy reservoir has been generated with the help of stochastic simulation technique, whose cross sections of channel-sandy reservoir are parabolic shapes. This method makes the hard data commendably meet, very suit for geological modeling of containing complex boundary surface reservoir. To verify reliability of the method, theoretical solution and numerical solution are compared by simplifying model of 3-dimension fluid equations in porous media, whose results show that the only difference of the two pressure curves is that the numerical solution is lower than theoretical at the wellbore in the same space. It proves that using finite difference to solve fluid equations in porous media is reliable. As numerical examples of 3-dimension heterogeneous reservoir of the single-well and multi-well, the pressure distributions have been computed respectively, which show the pressure distributions there are clearly difference as difference of the permeabilities is greater than one order of magnitude, otherwise there are no clearly difference. As application, the pressure distribution of the channel-sandy reservoir have been computed, which indicates that the space distribution of pressure strongly relies on the direction of permeability, and is sensitive for space distributions of permeability. In this dissertation, the Peaceman's equations have been modified into solving vertical well problem and horizontal well problem simultaneously. In porous media, a 3D layer reservoir in which contain vertical wells and horizontal wells has been calculated with iteration. For channel-sandy reservoir in which there are also vertical wells and horizontal wells, a 3D transient heterogeneous fluid equation has been discretized. As an example, the space distribution of pressure has been calculated with iteration. The results of examples are accord with the fact, which shows the modification of Peaceman's equation is correct. The problem has been solved in the space where there are vertical and horizontal wells. In the dissertation, the nonuniform grid permeability integration equation upscaling method, the nonuniform grid 2D flow rate upscaling method and the nonuniform grid 3D flow rate upscaling method have been studied respectively. In those methods, they enhance computing speed greatly, but the computing speed of 3D flow rate upscaling method is faster than that of 2D flow rate upscaling method, and the precision of 3D flow rate upscaling method is better than that of 2D flow rate upscaling method. The results also show that the solutions of upscaling method are very approximating to that of fine grid blocks. In this paper, 4 methods of fast adaptive nonuniform grid upscaling method of 3D fluid equations in porous media have been put forward, and applied to calculate 3D heterogeneous reservoir and channel-sandy reservoir, whose computing results show that the solutions of nonuniform adaptive upscaling method of 3D heterogeneous fluid equations in porous media are very approximating to that of fine grid blocks in the regions the permeability or porosity being abnormity and very approximating to that of coarsen grid blocks in the other region, however, the computing speed of adaptive upscaling method is 100 times faster than that of fine grid block method. The formula of sensitivity coefficients are derived from initial boundary value problems of fluid equations in porous media by Green's reciprocity principle. The sensitivity coefficients of wellbore pressure to permeability parameters are given by Peaceman's equation and calculated by means of numerical calculation method of 3D transient anisotropic fluid equation in porous media and verified by direct method. The computing results are in excellent agreement with those obtained by the direct method, which shows feasibility of the method. In the dissertation, the calculating examples are also given for 3D reservoir, channel-sandy reservoir and 3D multi-well reservoir, whose numerical results indicate: around the well hole, the value of the sensitivity coefficients of permeability is very large, the value of the sensitivity coefficients of porosity is very large too, but the sensitivity coefficients of porosity is much less than the sensitivity coefficients of permeability, so that the effect of the sensitivity coefficients of permeability for inversion of reservoir parameters is much greater than that of the sensitivity coefficients of porosity. Because computing the sensitivity coefficients needs to call twice the program of reservoir simulation in one iteration, realizing inversion of reservoir parameters must be sustained by the fast forward method. Using the sensitivity coefficients of permeability and porosity, conditioned on observed valley erosion thickness in wells (hard data), the inversion of the permeabilities and porosities in the homogeneous reservoir, homogeneous reservoir only along the certain direction and block reservoir are implemented by Gauss-Newton method or conjugate gradient method respectively. The results of our examples are very approximating to the real data of permeability and porosity, but the convergence rate of conjugate gradient method is much faster than that of Gauss-Newton method.

珠江口盆地流花11-1油田储层非均质性及流体分布规律研究

In order to discover the distribution law of the remaining oil, the paper focuses on the quantitative characterization of the reservoir heterogeneity and the distribution law of the fluid barrier and interbed, based on fine geological study of the reservoir in Liuhuall-1 oil field. The refined quantitative reservoir geological model has been established by means of the study of core analysis, logging evaluation on vertical well and parallel well, and seismic interpretation and prediction. Utilizing a comprehensive technology combining dynamic data with static data, the distribution characteristics, formation condition and controlling factors of remaining oil in Liuhuall-1 oil field have been illustrated. The study plays an important role in the enrichment regions of the remaining oil and gives scientific direction for the next development of the remaining oil. Several achievements have been obtained as follows: l.On the basis of the study of reservoir division and correlation,eight lithohorizons (layer A, B_1, B_2, B_3, C, D, E, and F) from the top to the bottom of the reservoir are discriminated. The reef facies is subdivided into reef-core facies, fore-reef facies and backreef facies. These three subfacies are further subdivided into five microfacies: coral algal limestone, coralgal micrite, coral algal clastic limestone, bioclastic limestone and foraminiferal limestone. In order to illustrate the distribution law of remaining oil in high watercut period, the stratigraphic structure model and sedimentary model are reconstructed. 2.1n order to research intra-layer, inter-layer and plane reservoir heterogeneity, a new method to characterize reservoir heterogeneity by using IRH (Index of Reservoir Heterogeneity) is introduced. The result indicates that reservoir heterogeneity is medium in layer B_1 and B_3, hard in layer A, B_2, C, E, poor in layer D. 3.Based on the study of the distribution law of fluid barrier and interbed, the effect of fluid battier and interbed on fluid seepage is revealed. Fluid barrier and interbed is abundant in layer A, which control the distribution of crude oil in reservoir. Fluid barrier and interbed is abundant relatively in layer B_2,C and E, which control the spill movement of the bottom water. Layer B_1, B_3 and D tend to be waterflooded due to fluid barrier and interbed is poor. 4.Based on the analysis of reservoir heterogeneity, fluid barrier and interbed and the distribution of bottom water, four contributing regions are discovered. The main lies on the north of well LH11-1A. Two minors lie on the east of well LH11-1-3 and between well LH11-1-3 and well LH11-1-5. The last one lies in layer E in which the interbed is discontinuous. 5.The parameters of reservoir and fluid are obtained recurring to core analysis, logging evaluation on vertical well and parallel well, and seismic interpretation and prediction. Theses parameters provide data for the quantitative characterization of the reservoir heterogeneity and the distribution law of the fluid barrier and interbed. 6.1n the paper, an integrated method about the distribution prediction of remaining oil is put forward on basis of refined reservoir geological model and reservoir numerical simulation. The precision in history match and prediction of remaining oil is improved greatly. The integrated study embodies latest trend in this research field. 7.It is shown that the enrichment of the remaining oil with high watercut in Liuhua 11-1 oil field is influenced by reservoir heterogeneity, fluid barrier and interbed, sealing property of fault, driving manner of bottom water and exploitation manner of parallel well. 8.Using microfacies, IRH, reservoir structure, effective thickness, physical property of reservoir, distribution of fluid barrier and interbed, the analysis of oil and water movement and production data, twelve new sidetracked holes are proposed and demonstrated. The result is favorable to instruct oil field development and have gotten a good effect.

花岗岩风化土微观结构及其工程地质特性研究

Saprolite is the residual soil resulted from completely weathered or highly weathered granite and with corestones of parent rock. It is widely distributed in Hong Kong. Slope instability usually happens in this layer of residual soil and thus it is very important to study the engineering geological properties of Saprolite. Due to the relic granitic texture, the deformation and strength characteristics of Saprolite are very different from normal residual soils. In order to investigate the effects of the special microstructure on soil deformation and strength, a series of physical, chemical and mechanical tests were conducted on Saprolite at Kowloon, Hong Kong. The tests include chemical analysis, particle size analysis, mineral composition analysis, mercury injection, consolidation test, direct shear test, triaxial shear test, optical analysis, SEM & TEM analysis, and triaxial shear tests under real-time CT monitoring.Based on the testing results, intensity and degree of weathering were classified, factors affecting and controlling the deformation and strength of Saprolite were identified, and the interaction between those factors were analyzed.The major parameters describing soil microstructure were introduced mainly based on optical thin section analysis results. These parameters are of importance and physical meaning to describe particle shape, particle size distribution (PSD), and for numerical modeling of soil microstructure. A few parameters to depict particle geometry were proposed or improved. These parameters can be used to regenerate the particle shape and its distribution. Fractal dimension of particle shape was proposed to describe irregularity of particle shapes and capacity of space filling quantitatively. And the effect of fractal dimension of particle shape on soil strength was analyzed. At the same time, structural coefficient - a combined parameter which can quantify the overall microstructure of rock or soil was introduced to study Saprolite and the results are very positive. The study emphasized on the fractal characteristics of PSD and pore structure by applying fractal theory and method. With the results from thin section analysis and mercury injection, it was shown that at least two fractal dimensions Dfl(DB) and Df2 (Dw), exist for both PSD and pore structure. The reasons and physical meanings behind multi-fractal dimensions were analyzed. The fractal dimensions were used to calculate the formation depth and weathering rate of granite at Kowloon. As practical applications, correlations and mathematical models for fractal dimensions and engineering properties of soil were established. The correlation between fractal dimensions and mechanical properties of soil shows that the internal friction angle is mainly governed by Dfl 9 corresponding to coarse grain components, while the cohesion depends on Df2 , corresponding to fine grain components. The correlations between the fractal dimension, friction angle and cohesion are positive linear.Fractal models of PSD and pore size distribution were derived theoretically. Fragmentation mechanism of grains was also analyzed from the viewpoint of fractal. A simple function was derived to define the theoretical relationship between the water characteristic curve (WCC) and fractal dimension, based on a number of classical WCC models. This relationship provides a new analytical tool and research method for hydraulic properties in porous media and solute transportation. It also endues fractal dimensions with new physical meanings and facilitates applications of fractal dimensions in water retention characteristics, ground water movement, and environmental engineering.Based on the conclusions from the fractal characteristics of Saprolite, size effect on strength was expressed by fractal dimension. This function is in complete agreement with classical Weibull model and a simple function was derived to represent the relationship between them.In this thesis, the phenomenon of multi-fractal dimensions was theoretically analyzed and verified with WCC and saprolite PSD results, it was then concluded that multi-fractal can describe the characteristics of one object more accurately, compared to single fractal dimension. The multi-fractal of saprolite reflects its structural heterogeneity and changeable stress environment during the evolution history.

Time-dependent wavepacket approach to the influence of intense fields on the population of molecular excited states

The influence of laser-field parameters, such as intensity and pulse width, on the population of molecular excited state is investigated by using the time-dependent wavepacket method. For a two-state system in intense laser fields, the populations in the upper and lower states are given by the wavefunctions obtained by solving the Schrodinger equation through split-operator scheme. The calculation shows that both the laser intensity and the pulse width have a strong effect on the population in molecular excited state, and that as the common feature of light-matter interaction (LMI), the periodic changing of the population with the evolution time in each state can be interpreted by Rabi oscillation and area-theorem. The results illustrate that by controlling these two parameters, the needed population in excited state of interest can be obtained, which provides the foundation of light manipulation of molecular processes. (C) 2005 Elsevier B.V. All rights reserved.

Na-23, Si-29, and C-13 MAS NMR investigation of glass-forming reactions between Na2CO3 and SiO2

Winter, Rudolf; Jones, A.R.; Greaves, G.N.; Smith, I.H., (2005) 'Na-23, Si-29, and C-13 MAS NMR investigation of glass-forming reactions between Na2CO3 and SiO2', Journal of Physical Chemistry B 109(49) pp.23154-23161 RAE2008

Técnicas e soluções para remoção da Smear Layer

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária

INVESTIGATION OF OCEAN ACOUSTICS USING AUTONOMOUS INSTRUMENTATION TO QUANTIFY THE WATER-SEDIMENT BOUNDARY PROPERTIES

Sound propagation in shallow water is characterized by interaction with the oceans surface, volume, and bottom. In many coastal margin regions, including the Eastern U.S. continental shelf and the coastal seas of China, the bottom is composed of a depositional sandy-silty top layer. Previous measurements of narrow and broadband sound transmission at frequencies from 100 Hz to 1 kHz in these regions are consistent with waveguide calculations based on depth and frequency dependent sound speed, attenuation and density profiles. Theoretical predictions for the frequency dependence of attenuation vary from quadratic for the porous media model of M.A. Biot to linear for various competing models. Results from experiments performed under known conditions with sandy bottoms, however, have agreed with attenuation proportional to f1.84, which is slightly less than the theoretical value of f2 [Zhou and Zhang, J. Acoust. Soc. Am. 117, 2494]. This dissertation presents a reexamination of the fundamental considerations in the Biot derivation and leads to a simplification of the theory that can be coupled with site-specific, depth dependent attenuation and sound speed profiles to explain the observed frequency dependence. Long-range sound transmission measurements in a known waveguide can be used to estimate the site-specific sediment attenuation properties, but the costs and time associated with such at-sea experiments using traditional measurement techniques can be prohibitive. Here a new measurement tool consisting of an autonomous underwater vehicle and a small, low noise, towed hydrophone array was developed and used to obtain accurate long-range sound transmission measurements efficiently and cost effectively. To demonstrate this capability and to determine the modal and intrinsic attenuation characteristics, experiments were conducted in a carefully surveyed area in Nantucket Sound. A best-fit comparison between measured results and calculated results, while varying attenuation parameters, revealed the estimated power law exponent to be 1.87 between 220.5 and 1228 Hz. These results demonstrate the utility of this new cost effective and accurate measurement system. The sound transmission results, when compared with calculations based on the modified Biot theory, are shown to explain the observed frequency dependence.

TCP over CDMA2000 Networks: A Cross-Layer Measurement Study

Modern cellular channels in 3G networks incorporate sophisticated power control and dynamic rate adaptation which can have a significant impact on adaptive transport layer protocols, such as TCP. Though there exists studies that have evaluated the performance of TCP over such networks, they are based solely on observations at the transport layer and hence have no visibility into the impact of lower layer dynamics, which are a key characteristic of these networks. In this work, we present a detailed characterization of TCP behavior based on cross-layer measurement of transport, as well as RF and MAC layer parameters. In particular, through a series of active TCP/UDP experiments and measurement of the relevant variables at all three layers, we characterize both, the wireless scheduler in a commercial CDMA2000 network and its impact on TCP dynamics. Somewhat surprisingly, our findings indicate that the wireless scheduler is mostly insensitive to channel quality and sector load over short timescales and is mainly affected by the transport layer data rate. Furthermore, we empirically demonstrate the impact of the wireless scheduler on various TCP parameters such as the round trip time, throughput and packet loss rate.