148 resultados para Geometrical transforms


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Godao area, located in the east of the Zhanhua depression of Jirang sag in Bohai Bay Basin, is the studying area in my dissertation. It is first time that fault sealing properties and the related relationship with the pool forming are studied in Gudao area. On the base of the analysis of the regional tectonics, the author has studied the tertiary structural evolution of the Gudao area and distinguished the fault's level and put forward the distinguishing principle. The geometrical feature, mechanical characters, developmental mechanism and history of the boundary faults in the tectonic unit of this area are all studied and emphasized especially. The buried history of oil-generating depression (that is Gudao depression) and the history of oil and gas migration simultaneously are discussed, the juxtaposition relationship between boundary fault evolutionary history and oil and gas migrated history are expatiated. To the geological condition of the Gudao area, three level faults sealing properties of this area were discussed in detail. Their characteristics of behavior and the intrinsic relationship between their sealing and oil and gas migrated reservoir are elucidated. The pool-forming models related to fault seal are exposed. The author has studied the lithologies of different order of faults, the relationship of occurrence assemblage analysis, normal stress of fault plane in different depth and shale smear factor faults. Then analysis their role in the various faults sealing and confirms fault sealing marks of three different orders faults and exposes the mechanism of fault sealing. Shale smear zone formed by first order fault in lasting activities is one different type of fault breccia and mainly controlled factor to its entrapment of petroleum. Effective sealing threshold value and fault displacement is ascertained. Mainly controlled factor of second fault sealing is bigger compressive stress loaded on fault plane. According to this, quantitatively evaluated index is given. Shale smear zone is necessary condition for second fault stress entrapment. The juxtaposed relationship between the different lithologies within third order faults is most important controlled factor for its sealing. Based on various order of fault sealing features and mechanism in Gudao area, the author proposed three orders of fault sealing models. Shale smear zone sealing model, normal stress sealing model and lithologies juxtaposed sealing model are suggested to first, second and third order fault respectively. The conclusion of this studying has not only the very important theoretical significance and practical value in Gudo area but also the very important guiding role for other areas of related aspects.

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With the development of the technology of earthquake observation, more and more researchers work at many fields' of seismicity using seismic kinetic property, as the result, the study of attenuation has also made great progress, especially in the mechanism of the attenuation and the physical process. Aki put forward single back scattering theory to explain the forming of the seismic coda wave in 1969. Then, researchers started to develop the study in seismic scattering and attenuation. My thesis is also based on that theory. We assume that the Lg wave is a superposition fo high-mode surface waves, the coda of Lg is caused by scattering. Sato proposed Single Isotropic Scattering model (SIS model) to interpreted the scatter property, and he also formulated the geometrical spreading term. Then Xie (1988) developed the single spectral-ratio (SSR) method to obtain the Lg coda Q and the frequency dependent factor n. Later, he get to lateral images in the area of scatter ellipse. SSR method is explored and used in the study of Lg coda waves of regional earthquakes in my thesis. Choosing the earthquakes records with high ratio of signal-noise ,which were recorded at the stations from 1989 to 1999, we obtain the single trace Lg coda Q and its frequency dependent factor n. The results proved that SIS model is the reasonable model to explain the Lg coda wave, and SSR method also can be used to process Lg coda of regional earthquakes to get to the satisfied Lg coda Q. Based on the Lg coda Q we obtained using the former method, we explore the programs to inverse the regional Lg coda Q independently, and then make use of them to inverse the Lg coda Q of Beijing and adjacent area. The inversion result is satisfied. We conclude that the distribution of Qo (Q in lHz) is marked by the inhomogeneity, which is related to the tectonic structure: The value of Qo in uplift area, for example, Yanshan uplift, Taihang uplift, Luxi Uplift, is higher than the depression area, for example, Jizhong depression, Huanghua depression, and Jiyang depression, and the border between the higher Q area and lower Q area is very clear; Lg coda Q is also related to the velocity structure, higher velocity area is also with higher Q, lower velocity area is with lower Q; and higher heat-flow area is companied with lower Q. All in all, the value of Q reflects the difference of characteristics of lithofaces, porosity, the liquid content between the pores and heat flow. So, the Q value difference between uplift area and depression area reveals the difference of tectonic structure, lithology and physical character of the rock. So, the study of Lg coda Q is help to understand the earthquakes propagation mechanism through the inhomogenous medium, the cause of the coda, attenuation mechanism of the coda. Making use of the lateral images of Q, with velocity images, heat flow results, and other experimental result, we will be promoted to understand the complex structure of the crust, its inhomogenous character, and so on.

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In the increasingly enlarged exploration target, deep target layer(especially for the reservoir of lava) is a potential exploration area. As well known, the reflective energy becomes weak because the seismic signals of reflection in deep layer are absorbed and attenuate by upper layer. Caustics and multi-values traveltime in wavefield are aroused by the complexity of stratum. The ratio of signal to noise is not high and the fold numbers are finite(no more than 30). All the factors above affect the validity of conventional processing methods. So the high S/N section of stack can't always be got with the conventional stack methods even if the prestack depth migration is used. So it is inevitable to develop another kind of stack method instead. In the last a few years, the differential solution of wave equation was hold up by the condition of computation. Kirchhoff integral method rose in the initial stages of the ninetieth decade of last century. But there exist severe problems in it, which is are too difficult to resolve, so new method of stack is required for the oil and gas exploration. It is natural to think about upgrading the traditionally physic base of seismic exploration methods and improving those widely used techniques of stack. On the other hand, great progress is depended on the improvement in the wave differential equation prestack depth migration. The algorithm of wavefield continuation in it is utilized. In combination with the wavefield extrapolation and the Fresnel zone stack, new stack method is carried out It is well known that the seismic wavefield observed on surface comes from Fresnel zone physically, and doesn't comes from the same reflection points only. As to the more complex reflection in deep layer, it is difficult to describe the relationship between the reflective interface and the travel time. Extrapolation is used to eliminate caustic and simplify the expression of travel time. So the image quality is enhanced by Fresnel zone stack in target. Based on wave equation, high-frequency ray solution and its character are given to clarify theoretical foundation of the method. The hyperbolic and parabolic travel time of the reflection in layer media are presented in expression of matrix with paraxial ray theory. Because the reflective wave field mainly comes from the Fresnel Zone, thereby the conception of Fresnel Zone is explained. The matrix expression of Fresnel zone and projected Fresnel zone are given in sequence. With geometrical optics, the relationship between object point in model and image point in image space is built for the complex subsurface. The travel time formula of reflective point in the nonuniform media is deduced. Also the formula of reflective segment of zero-offset and nonzero offset section is provided. For convenient application, the interface model of subsurface and curve surface derived from conventional stacks DMO stack and prestack depth migration are analyzed, and the problem of these methods was pointed out in aspects of using data. Arc was put forward to describe the subsurface, thereby the amount of data to stack enlarged in Fresnel Zone. Based on the formula of hyperbolic travel time, the steps of implementation and the flow of Fresnel Zone stack were provided. The computation of three model data shows that the method of Fresnel Zone stack can enhance the signal energy and the ratio of signal to noise effectively. Practical data in Xui Jia Wei Zhi, a area in Daqing oilfield, was processed with this method. The processing results showed that the ability in increasing S/N ratio and enhancing the continuity of weak events as well as confirming the deep configuration of volcanic reservoir is better than others. In deeper target layer, there exists caustic caused by the complex media overburden and the great variation of velocity. Travel time of reflection can't be exactly described by the formula of travel time. Extrapolation is bring forward to resolve the questions above. With the combination of the phase operator and differential operator, extrapolating operator adaptable to the variation of lateral velocity is provided. With this method, seismic records were extrapolated from surface to any different deptlis below. Wave aberration and caustic caused by the inhomogenous layer overburden were eliminated and multi-value curve was transformed into the curve.of single value. The computation of Marmousi shows that it is feasible. Wave field continuation extends the Fresnel Zone stack's application.

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This article is an important part of "95" technological subject of SINOPEC. It has a large number of difficulties and workloads, and has significant theoretical meanings and practical value. The study area is composed of sandstone & conglomerate reservoir of alluvial fan & fan delta, which belong to Sha3 lower member and Sha4 upper member of lower tertiary of Yong'an Town Oilfield in Dongying Depression. The target stataum develops in the hanging wall of the synsedimentary fault in the scarp zone of Dongying Depression. The frequently intense movements result in the variation of sandstone and conglomerate reservoir and the evolution of the time and space of Sha3 lower member and Sha4 upper member in Yong'an Town Oilfield. As a result, it is difficult for the individual reservoir correlation at the root of fan, which bring about a tackle problem for the exploitation of oilfield. In this background, the research of fluid units will be more difficult. In this article, the new concepts, the new methods, and the new techniques of sedimentology, petroleum geology, reservoir geology, physics of crystal surface, dynamic & static state reservoir description and well logging geology are synthetically applied, and the computer technology are made full uses of, and the identifying, dividing and appraising of the two-formation-type sandstone & conglomerate reservoir fluid units of Sha3 lower member and Sha4 upper member systemically analyzed in Yong'an Town Oilfield, Dongying Depression. For the first time, the single-well model, the section model, the plane model, the nuclear magnetism log model, the microcosmic network model, the 4-D geology model and the simulation model of the two-formation-type reservoir fluid units of the of sandstone & conglomerate reservoir of Sha3 lower member and Sha4 upper member are established, and the formative mechanism and distributing & enrichment laws of oil-gas of the two type of sandstone and conglomerate reservoir fluid units are revealed. This article established the optimizing, identifying, classifying and appraising standard of the two-formation-type reservoir fluid units of the of sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member, which settles the substantial foundations for static state model of the fluid units, reveals the macroscopic & microcosmic various laws of geometrical static state of the fluid units, and instructs the oil exploitation. This article established static state model of the two-formation-type sandstone and conglomerate reservoir fluid units by using the multi-subject theories, information and techniques, and reveals the geometrical configuration, special distribution and the oil-gas enrichment laws of the sandstone and conglomerate reservoir fluid units. For the first time, we established the nuclear magnetism log model of the two-formation-type sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member, which reveals not only the character and distributing laws of the porosity and permeability, bat also the formation and distribution of the movable fluid. It established six type of microcosmic net model of the two-formation-type sandstone and conglomerate reservoir of Sha3 lower member and Sha4 upper member in the working area by using the advanced theories, such as rock thin section, SEM, image analysis, intrusive mercury, mold, rock C.T. measure & test image etc., which reveals the microcosmic characteristic of porosity & throat, filterate mode and microcosmic oil-gas enrichment laws of the sandstone and conglomerate reservoir. For the first time, it sets up the 4-D model and mathematic model of the sandstone and conglomerate reservoir, which reveals the distributing and evolving laws of macroscopic & microcosmic parameters of the two-formation-type sandstone and conglomerate reservoir and oil-gas in 4-D space. At the same time, it also forecasts the oil-gas distribution and instructs the oilfield exploitation. It established reservoir simulation model, which reveals the filterate character and distributing laws of oil-gas in different porosity & throat net models. This article established the assistant theories and techniques for researching, describing, indicating and forecasting the sandstone and conglomerate reservoir fluid units, and develops the theories and techniques of the land faces faulted basin exploitation geology. In instructing oilfield exploitation, it had won the notable economic & social benefits.

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The foundation of reservoir model and residual oil prediction have been the core of reservoir detailed description for improved oil production and enhanced oil recovery. The traditional way of sandstone correlation based on the geometrical similarity of well-logs which emphasizes "based on the cycle and correlating from larger to smaller" has shown its theoretical limits when explaining the correlating and the scale, geometry, continuity, connectivity of sandstones and the law of the reservoir property. It has been an urgent and difficult subject to find new theory and methods to solve the reservoir correlation and property prediction. It's a new way to correlate strata and found framework of reservoir through the process-response analysis in the base-level cycles. And it is also possible to analyze the reservoir property in reservoir framework. Taking the reservoir of zonation 6-10 in S3~2 of Pucheng Oil Field in Henan Province as an example, we founded the detailed reservoir stratigraphic framework through base-level correlation. In the strata frame, sediment distribution and its development are discussed based on sediment volume partitioning and facies differentiation analysis. Reservoir heterogeneities and its relation to base-level are also discussed. The analysis of primary oil distribution shows the base-level controlled oil distribution in reservoir. In this paper, subjects as following are discussed in detail. Based on the analysis of sedimentary structure and sedimentary energy, the facies model was founded. Founding stratigraphy framework through base level analysis In the studying zone, one long term cycle, 6 middle term cycles and 27 short term cycles was identified and correlated. 3 Predicting the property of reservoir for improving oil development The base level controlled the property of sandbody. The short and very short term cycle controlled the pattern of heterogeneities in sandbody, and the middle and long term cycle controlled the area and inter-layer heterogeneities. On the lower location of the middle and long term base level, the sandbody is well developed, with a wide area and large thickness, while on the high location of base level, there is an opposite reservoir character. 4 The studying of reservoir development response and oil distribution making a solid base for development adjustment Primary oil distribution is controlled by base level location. It tells that the sandbody on the high base level location was poor developed for its difficulty to develop. While on the low location of the base level, the sandbody is well developed for its relative easy to develop and dominant role in the development, but high residual oil for its high original oil content.

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Rockfall is a geological evolution process involving detachment of blocks or boulders from a slope face, then their free falls, bouncing, rolling or sliding, and finally deposition near the toe of the slope. Many facts indicate that the rockfall can cause hazards to peoples, and it can be regarded as a geological hazard. A rockfall event may only involve a boulder or rock, and also several ones. When there are peoples, buildings, or other man-made establishments within the scope of rockfall trajectory, losses will be possibly induced in tenns of human lives or damages to these facilities. Researches into mechanism, kinematics, dynamics, hazard assessment, risk analysis, and mitigation measures of rockfalls are extremely necessary and important. Occurrence of rockfall is controlled by a lot of conditions, mainly including topographical, geomorphic, geological ones and triggering factors. The rockfall especially in mountainous areas, has different origins, and occurs to be frequent, unexpected, uncertain, in groups, periodic and sectional. The characterization and classification of the rockfalls not only increase knowledge about rockfall mechanism, but also can instruct mitigation of the hazards. In addition, stability of potential rockfalls have various sensitivity to different triggering factors and changes of geometrical conditions. Through theoretical analyses, laboratory experiments and field tests, the author presents some back-analysis methods for friction coefficients of sliding and rolling, and restitution coefficients. The used input data can be obtained economically and accurately in the field. Through deep studies on hazard assessment methods and analysis of factors influencing rockfall hazard, this paper presents a new assessment methodology consisting of preliminary assessment and detailed one. From the application in a 430 km long stretch of the Highway, which is located between Paksho and Nyingtri in Tibet, the methodology can be applicable for the rockfall hazard assessment in complex and difficult terrains. In addition, risk analyses along the stretch are conducted by computing the probability of encountering rockfalls and life losses resulting from rockfall impacts. Rockfall hazards may be mitigated by avoiding hazardous areas, clearness of dangerous rocks, reinforcement, obstructing the rockfalls, leading the rockfalls, warning and monitoring for rockfalls, etc. Seen from present remedial level of rockfall hazards, different mitigation measures, economical and effective buffering units, monitoring tecliniques and consciousness of environmental protection for rockfall mitigations should be further developed.

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With the development of oil and gas exploration, the exploration of the continental oil and gas turns into the exploration of the subtle oil and gas reservoirs from the structural oil and gas reservoirs in China. The reserves of the found subtle oil and gas reservoirs account for more than 60 percent of the in the discovered oil and gas reserves. Exploration of the subtle oil and gas reservoirs is becoming more and more important and can be taken as the main orientation for the increase of the oil and gas reserves. The characteristics of the continental sedimentary facies determine the complexities of the lithological exploration. Most of the continental rift basins in East China have entered exploration stages of medium and high maturity. Although the quality of the seismic data is relatively good, this areas have the characteristics of the thin sand thickness, small faults, small range of the stratum. It requests that the seismic data have high resolution. It is a important task how to improve the signal/noise ratio of the high frequency of seismic data. In West China, there are the complex landforms, the deep embedding the targets of the prospecting, the complex geological constructs, many ruptures, small range of the traps, the low rock properties, many high pressure stratums and difficulties of boring well. Those represent low signal/noise ratio and complex kinds of noise in the seismic records. This needs to develop the method and technique of the noise attenuation in the data acquisition and processing. So that, oil and gas explorations need the high resolution technique of the geophysics in order to solve the implementation of the oil resources strategy for keep oil production and reserves stable in Ease China and developing the crude production and reserves in West China. High signal/noise ratio of seismic data is the basis. It is impossible to realize for the high resolution and high fidelity without the high signal/noise ratio. We play emphasis on many researches based on the structure analysis for improving signal/noise ratio of the complex areas. Several methods are put forward for noise attenuation to truly reflect the geological features. Those can reflect the geological structures, keep the edges of geological construction and improve the identifications of the oil and gas traps. The ideas of emphasize the foundation, give prominence to innovate, and pay attention to application runs through the paper. The dip-scanning method as the center of the scanned point inevitably blurs the edges of geological features, such as fault and fractures. We develop the new dip scanning method in the shap of end with two sides scanning to solve this problem. We bring forward the methods of signal estimation with the coherence, seismic wave characteristc with coherence, the most homogeneous dip-sanning for the noise attenuation using the new dip-scanning method. They can keep the geological characters, suppress the random noise and improve the s/n ratio and resolution. The rutine dip-scanning is in the time-space domain. Anew method of dip-scanning in the frequency-wavenumber domain for the noise attenuation is put forward. It use the quality of distinguishing between different dip events of the reflection in f-k domain. It can reduce the noise and gain the dip information. We describe a methodology for studying and developing filtering methods based on differential equations. It transforms the filtering equations in the frequency domain or the f-k domain into time or time-space domains, and uses a finite-difference algorithm to solve these equations. This method does not require that seismic data be stationary, so their parameters can vary at every temporal and spatial point. That enhances the adaptability of the filter. It is computationally efficient. We put forward a method of matching pursuits for the noise suppression. This method decomposes any signal into a linear expansion of waveforms that are selected from a redundant dictionary of functions. These waveforms are chosen in order to best match the signal structures. It can extract the effective signal from the noisy signal and reduce the noise. We introduce the beamforming filtering method for the noise elimination. Real seismic data processing shows that it is effective in attenuating multiples and internal multiples. The s/n ratio and resolution are improved. The effective signals have the high fidelity. Through calculating in the theoretic model and applying it to the real seismic data processing, it is proved that the methods in this paper can effectively suppress the random noise, eliminate the cohence noise, and improve the resolution of the seismic data. Their practicability is very better. And the effect is very obvious.

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It has been a difficult problem faced by seismologists for long time that how exactly to reconstruct the earth's geometric structure and distribution of physical attributes according to seismic wave's kinematical and dynamic characteristics, obtained in seismological observation. The jointing imaging of seismic reflector and anisotropy attributes in the earth interior is becoming the research hot spot. The limitation of shoot and observation system makes that the obtained seismic data are too scarce to exactly reconstruct the geological objects. It is popular that utilizing only seismic reflection traveltimes or polarizations information make inversion of the earth's velocity distribution by fixing seismic reflector configuration (vice versa), these will lead to the serious non-uniqueness reconstruction due to short of effective data, the non-uniqueness problem of reconstructing anisotropy attributes will be more serious than in isotropy media. Obviously it is not enough to restrict the media structure only by information of seismic reflection traveltimes or polarizations, which even sometimes will lead to distorted images and misinterpretation of subsurface structure. So we try to rebuild seismic reflection structure (geometry) and media anisotropic structure (physics) in the earth interior by jointing data of seismic wave kinematics and dynamics characteristics, we carry out the new experiment step by step, and the research mainly comprises of two parts: one is the reconstruction of P-wave vertical velocity and anisotropic structure(Thomsen parameter s and 8) in the transversely isotropic media with vertical symmetrical axis(VTI) by fixing geometrical structure, and the other is the simultaneous inversion of the reflector surface conformation and seismic anisotropic structure by jointing seismic reflection traveltimes and polarizations data. Simulated annealing method is used to the first research part, linear inversion based on BG theory and Simulated annealing are applied to the second one. All the research methods are checked by model experiments, then applied to the real data of the wide-angle seismic profile from Tunxi, Anhui Province, to Wenzhou, Zhejiang Province. The results are as following The inversion results based on jointing seismic PP-wave or PSV-wavereflection traveltimes and polarizations data are more close to real model than themodels based simply on one of the two data respectively. It is shown that the methodwe present here can effectively reconstruct the anisotropy attributes in the earth'sinterior when seismic reflector structure is fixed.The layer thickness, P-wave vertical velocity and Thomsen anisotropicparameters {s and 8) could be resolved simultaneously by jointing inversion ofseismic reflection traveltimes and polarizations with the linear inversion methodbased on BG theory.The image of the reflector structure, P-wave vertical velocity and theanisotropy parameters in the crust could be obtained from the wide-angle seismicprofile from Tunxi (in Anhui Province), to Wenzhou (in Zhejiang Province). Theresults reveal the difference of the reflector geometrical structure and physicalattributes in the crust between Yangtze block and Cathaysia block, and attempt tounderstand the characteristics of the crustal stress field in the areas.

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Ordos Basin is a typical cratonic petroliferous basin with 40 oil-gas bearing bed sets. It is featured as stable multicycle sedimentation, gentle formation, and less structures. The reservoir beds in Upper Paleozoic and Mesozoicare are mainly low density, low permeability, strong lateral change, and strong vertical heterogeneous. The well-known Loess Plateau in the southern area and Maowusu Desert, Kubuqi Desert and Ordos Grasslands in the northern area cover the basin, so seismic data acquisition in this area is very difficult and the data often takes on inadequate precision, strong interference, low signal-noise ratio, and low resolution. Because of the complicated condition of the surface and the underground, it is very difficult to distinguish the thin beds and study the land facies high-resolution lithologic sequence stratigraphy according to routine seismic profile. Therefore, a method, which have clearly physical significance, based on advanced mathematical physics theory and algorithmic and can improve the precision of the detection on the thin sand-peat interbed configurations of land facies, is in demand to put forward.Generalized S Transform (GST) processing method provides a new method of phase space analysis for seismic data. Compared with wavelet transform, both of them have very good localization characteristics; however, directly related to the Fourier spectra, GST has clearer physical significance, moreover, GST adopts a technology to best approach seismic wavelets and transforms the seismic data into time-scale domain, and breaks through the limit of the fixed wavelet in S transform, so GST has extensive adaptability. Based on tracing the development of the ideas and theories from wavelet transform, S transform to GST, we studied how to improve the precision of the detection on the thin stratum by GST.Noise has strong influence on sequence detecting in GST, especially in the low signal-noise ratio data. We studied the distribution rule of colored noise in GST domain, and proposed a technology to distinguish the signal and noise in GST domain. We discussed two types of noises: white noise and red noise, in which noise satisfy statistical autoregression model. For these two model, the noise-signal detection technology based on GST all get good result. It proved that the GST domain noise-signal detection technology could be used to real seismic data, and could effectively avoid noise influence on seismic sequence detecting.On the seismic profile after GST processing, high amplitude energy intensive zone, schollen, strip and lentoid dead zone and disarray zone maybe represent specifically geologic meanings according to given geologic background. Using seismic sequence detection profile and combining other seismic interpretation technologies, we can elaborate depict the shape of palaeo-geomorphology, effectively estimate sand stretch, distinguish sedimentary facies, determine target area, and directly guide oil-gas exploration.In the lateral reservoir prediction in XF oilfield of Ordos Basin, it played very important role in the estimation of sand stretch that the study of palaeo-geomorphology of Triassic System and the partition of inner sequence of the stratum group. According to the high-resolution seismic profile after GST processing, we pointed out that the C8 Member of Yanchang Formation in DZ area and C8 Member in BM area are the same deposit. It provided the foundation for getting 430 million tons predicting reserves and unite building 3 million tons off-take potential.In tackling key problem study for SLG gas-field, according to the high-resolution seismic sequence profile, we determined that the deposit direction of H8 member is approximately N-S or NNE-SS W. Using the seismic sequence profile, combining with layer-level profile, we can interpret the shape of entrenched stream. The sunken lenticle indicates the high-energy stream channel, which has stronger hydropower. By this way we drew out three high-energy stream channels' outline, and determined the target areas for exploitation. Finding high-energy braided river by high-resolution sequence processing is the key technology in SLG area.In ZZ area, we studied the distribution of the main reservoir bed-S23, which is shallow delta thin sand bed, by GST processing. From the seismic sequence profile, we discovered that the schollen thick sand beds are only local distributed, and most of them are distributary channel sand and distributary bar deposit. Then we determined that the S23 sand deposit direction is NW-SE in west, N-S in central and NE-SW in east. The high detecting seismic sequence interpretation profiles have been tested by 14 wells, 2 wells mismatch and the coincidence rate is 85.7%. Based on the profiles we suggested 3 predicted wells, one well (Yu54) completed and the other two is still drilling. The completed on Is coincident with the forecastThe paper testified that GST is a effective technology to get high- resolution seismic sequence profile, compartmentalize deposit microfacies, confirm strike direction of sandstone and make sure of the distribution range of oil-gas bearing sandstone, and is the gordian technique for the exploration of lithologic gas-oil pool in complicated areas.

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Ammonia adsorption studies reveal that the observed Lewis acidity in the zeolite MCM-22 is derived from at least two types of framework aluminum sites (Al(F)), that is, octahedral Al(F) and three-coordinate Al(F). Comparative ammonia or trimethylphosphine (TMP) adsorption experiments with MCM-22 confirm that octahedral Al species gives rise to the signal at delta(ISO) approximate to 0 in the (27)Al NMR spectrum; this is a superposition of two NMR signals from the different Al species on the water-re constructed zeolite surface. A sharp resonance assigned to framework Al reversibly transforms on ammonia adsorption to delta(ISO) (27)Al approximate to 55 from tetrahedral Al(F), while the broad peak is assigned to nonframework aluminium which results from hydrothermal treatment. This study also demonstrates the effectiveness of (27)Al magic angle spinning (MAS) and multiple quantum (MQ) MAS NMR spectroscopy as a technique for the study of zeolite reactions.

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General expressions used for transforming raw laser-induced fluorescence (LIF) intensity into the population and alignment parameters of a symmetric top molecule are derived by employing the density matrix approach. The molecular population and alignment are described by molecular state multipoles. The results are presented for a general excitation-detection geometry and then applied to some special geometries. In general cases, the LIF intensity is a complex function of the initial molecular state multipoles, the dynamic factors and the excitation-detection geometrical factors. It contains a population and 14 alignment multipoles. How to extract all initial state multipoles from the rotationally unresolved emission LIF intensity is discussed in detail.

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General expressions used for extracting the orientation and alignment parameters of a symmetric top molecule from laser-induced fluorescence (LIF) intensity are derived by employing the density matrix approach. The molecular orientation and alignment are described by molecular state multipoles. Excitation and detection are circularly and linearly polarized lights, respectively. In general cases, the LIF intensity is a complex function of the initial molecular state multipoles, the dynamic factors and the excitation-detection geometrical factors. It contains a population, ten orientation and fourteen alignment multipoles. The problem of how to extract the initial molecular state multipoles from the resolved LIF intensity is discussed.

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Expressions used for extracting the population and alignment parameters of a symmetric top molecule from (n + 1) laser-induced fluorescence (LIF) are derived by employing the tensor density matrix method. The molecular population and alignment are described by molecular state multipoles. The LIF intensity is a complex function of the initial molecular state multipoles, the dynamic factors, and the excitation-detection geometrical factors. The problem of how to extract the initial molecular state multipoles from (2 + 1) LIF, as an example, is discussed in detail. (C) 2000 American Institute of Physics. [S0021-9606(00)30744-9].