COMPARATIVE-STUDY OF KALMAN FILTERING, SYNCHRONOUS EXCITATION AND NUMERICAL DERIVATIVE TECHNIQUES IN FLUOROMETRY

The performance of Kalman filtering, synchronous excitation and numerical derivative techniques for the resolution of overlapping emission spectra in spectrofluorimetry was studied. The extent of spectrum overlap was quantitatively described by the separation degree D(s), defined as the ratio of the peak separation to the full width at half-maximum of the emission spectrum of the interferent. For the system of Rhodamine B and Rhodamine 6G with a large D(s) of about 0.4, both Kalman filtering and synchronous techniques are able to resolve the overlapping spectra well and to give satisfactory results while the derivative spectra are still overlapped with each other. Moreover, the sensitivities are greatly decreased in derivative techniques. For more closely spaced spectra emitted by the complexes of Al and Zn with 7-iodo-8-hydroxyquinoline-5-sulphonic acid (Ferron)-hexadecyltrimethylammonium bromide, the synchronous excitation technique cannot completely separate the overlapping peaks, although it increases the separation degree from 0.25 in the conventional spectra to 0.37 in the synchronous spectra. On the other hand, Kalman filtering is capable of resolving this system. When the Al/Zn intensity ratio at the central wavelength of Al was > 1, however, the accuracy and precision of the estimates for Zn concentration produced by the Kalman filter became worse. In this event, the combination of synchronous excitation and Kalman filtering can much improve the analytical results.

ON THE SIGNIFICANCE OF WAVELENGTH POSITIONING ACCURACY IN MULTICOMPONENT ANALYSIS TECHNIQUES FOR THE CORRECTION OF LINE INTERFERENCES IN INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

The present paper reports some definite evidence for the significance of wavelength positioning accuracy in multicomponent analysis techniques for the correction of line interferences in inductively coupled plasma atomic emission spectrometry (ICP-AES). Using scanning spectrometers commercially available today, a large relative error, DELTA(A) may occur in the estimated analyte concentration, owing to wavelength positioning errors, unless a procedure for data processing can eliminate the problem of optical instability. The emphasis is on the effect of the positioning error (deltalambda) in a model scan, which is evaluated theoretically and determined experimentally. A quantitative relation between DELTA(A) and deltalambda, the peak distance, and the effective widths of the analysis and interfering lines is established under the assumption of Gaussian line profiles. The agreement between calculated and experimental DELTA(A) is also illustrated. The DELTA(A) originating from deltalambda is independent of the net analyte/interferent signal ratio; this contrasts with the situation for the positioning error (dlambda) in a sample scan, where DELTA(A) decreases with an increase in the ratio. Compared with dlambda, the effect of deltalambda is generally less significant.

WAVELENGTH POSITIONING ERRORS AND TRUE DETECTION LIMIT IN RELATION TO MULTICOMPONENT ANALYSIS TECHNIQUES FOR THE CORRECTION OF LINE INTERFERENCES IN INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

The present paper deals with the evaluation of the relative error (DELTA(A)) in estimated analyte concentrations originating from the wavelength positioning error in a sample scan when multicomponent analysis (MCA) techniques are used for correcting line interferences in inductively coupled plasma atomic emission spectrometry. In the theoretical part, a quantitative relation of DELTA(A) with the extent of line overlap, bandwidth and the magnitude of the positioning error is developed under the assumption of Gaussian line profiles. The measurements of eleven samples covering various typical line interferences showed that the calculated DELTA(A) generally agrees well with the experimental one. An expression of the true detection limit associated with MCA techniques was thus formulated. With MCA techniques, the determination of the analyte and interferent concentrations depend on each other while with conventional correction techniques, such as the three-point method, the estimate of interfering signals is independent of the analyte signals. Therefore. a given positioning error results in a larger DELTA(A) and hence a higher true detection limit in the case of MCA techniques than that in the case of conventional correction methods. although the latter could be a reasonable approximation of the former when the peak distance expressed in the effective width of the interfering line is larger than 0.4. In the light of the effect of wavelength positioning errors, MCA techniques have no advantages over conventional correction methods unless the former can bring an essential reduction ot the positioning error.

IMPROVEMENT OF SELECTIVITY WITH NUMERICAL DERIVATIVE TECHNIQUES IN INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY

One of the most attractive features of derivative spectrometry is its higher resolving power. In the present power, numerical derivative techniques are evaluated from the viewpoint of increase in selectivity, the latter being expressed in terms of the interferent equivalent concentration (IEC). Typical spectral interferences are covered, including flat background, sloped background, simple curved background and various types of line overlap with different overlapping degrees, which were defined as the ratio of the net interfering signal at the analysis wavelength to the peak signal of the interfering line. the IECs in the derivative spectra are decreased by one to two order of magnitudes compared to those in the original spectra, and in the most cases, assume values below the conventional detection limits. The overlapping degree is the dominant factor that determines whether an analysis line can be resolved from an interfering line with the derivative techniques. Generally, the second derivative technique is effective only for line overlap with an overlapping degree of less than 0.8. The effects of other factors such as line shape, data smoothing, step size and the intensity ratio of analyte to interferent on the performance of the derivative techniques are also discussed. All results are illustrated with practical examples.

Zoospores of Undaria pinnatifida: their efficiency to attach under different water velocities and conjugation behavior during attachment

In the invading course of Undaria pinnatifida, zoospore attachment in a dynamically changed subtidal water environment is crucial for the establishment of a potential population in alien waters. Among many abiotic factors that may interfere with the attachment process, water velocity is the most important one. In this investigation, the effect of water velocity on zoospore attachment of U. pinnatifida was investigated in an artificially designed system. It was found that freshly released zoospores that were transported by water flowing at 0 similar to 16 cm/s showed no difficulty in attaching the smooth surface. Zoospore attachment decreased at elevated water flowing rates. At 70 cm/s no spore attachment occurred. Spores that have settled on glass slide for up to I h could not be stripped away by flowing water at a rate of 129 cm/s, the same was true of the 20 d old filamentous gametophytes. It was found that more than 70% of free-swimming zoospores tended to settle down adjacent to the settled spores and formed conjugated clusters from two up to a few hundred cells in still culture.

Modern changes of tidal troughs among the radial sand ridges in northern Jiangsu coastal zone

Using satellite images taken on different dates, GIS analysis of aerial photos, bathymetric maps and other field survey data, tidal troughs and major sand ridges in the northern Jiangsu coastal area were contrasted. The results show that there have been three types of movement or migration of tidal trough in this area: (1) Periodic and restricted, this type of trough usually developed along the beaches with immobile gully head as a result of the artificial dams and the swing range increased from gully head to the low reaches, so they have been obviously impacted by human activity and have longer swing periods; (2) Periodic and actively, this kind of trough, which swung with a fast rate and moved periodically on sand ridges, were mainly controlled by the swings of the host tidal troughs and hydrodynamic forces upon tidal sand ridge and influenced slightly by human constructions; (3) Steadily and slowly, they are the main tidal troughs with large scale and a steady orientation in this area and have slow lateral movement. The differences in migration mode of tidal trough shift result in different rates of migration and impact upon tidal sand ridges. Lateral accumulation on current tidal trough and deposition on abandoned tidal troughs are the two types of sedimentation of the tidal sand ridges formation. The whole radial sand ridge was generally prone to division and retreat although sand ridges fluctuated by the analysis of changes in talwegs of tidal troughs and shorelines of sand ridges.

On the relationships between the radial tidal current field and the radial sand ridges in the southern Yellow Sea: a numerical simulation

The ori-in of the radial sand ridges (RSRs) in the southern Yellow Sea has been a controversial problem since they were discovered in the early 1960s. To resolve the problem, two key questions need to be answered: (1) was the radial tidal current field in the RSR area generated by the submarine topography, or (2) did it exist before the RSRs occurred? In this study, the M-2 tide and tidal currents in the RSR area were simulated with a two-dimensional tidal model using a flat bottom and a shelving slope topography, the results being then compared with the field data. It is demonstrated that the radial tidal current field in the southern Yellow Sea is independent of bottom topography, and may thus be the controlling factor generating the RSRs. The radial tidal current field probably existed before the RSRs were formed.

淤泥质潮滩地貌的遥感研究－以苏北辐射沙洲海岸为例

本文以具有典型特征的苏北淤泥质潮滩海岸作为研究区，利用1975-2003年间14景覆盖该地区的Landsat和SPOT卫星影像作为主要数据源，结合地面调查和验证工作，在遥感影像处理和地理信息系统分析技术的支持下，对区内潮滩、岸线、水边线和盐沼植被等进行遥感解译，分析苏北辐射沙脊群和沿岸地貌的空间分布特征和动态演变趋势。研究结果表明：苏北辐射沙脊群海域的潮汐水位过程的不同步现象普遍存在，限制了常规遥感数据在苏北潮滩地貌研究中的适用范围和解译精度；在人工判别的辅助下，多光谱遥感的非监督分类方法可以有效解译淤泥质潮滩的水边线；利用修改型土壤调整植被指数（MSAVI）可以较好地提取潮滩上的盐沼植被信息；苏北沿岸潮滩的快速淤长促进了盐沼植被带向海侧快速扩展，近年来持续的潮滩围垦工程则不断从陆侧侵占盐沼植被带，使盐沼植被带宽度减小乃至消失；在大规模人类活动和自然条件的共同影响下，苏北辐射沙脊群海岸的岸线发育趋于平直化，无序的潮滩围垦项目使得可垦滩地资源被过度消耗；1975～2002年间，研究区北部和南部沿岸的高潮滩整体上处于淤长状态，中部沿岸潮滩和离岸沙洲高潮滩则被大面积侵蚀；1999年以来，研究区内低潮滩部位开始形成有序排列的滩面地物，并表现出逐年大面积蔓延的趋势，可能是滩涂紫菜养殖区扩展的结果。

鄂尔多斯盆地上古生界低渗透砂岩有效储层识别与预测

Sulige Gasfield, with a basically proven reserve as high as one trillion cubic meters, is one giant gas field discovered in China. The major gas -bearing layers are Upper Paleozoic strata with fluvial-lacustrine sedimentary facies. Generally, gas reservoirs in this field are characteristic by "five low" properties, namely low porosity, low permeability, low formation pressure, low productivity and low gas abundance. Reservoirs in this field also feature in a large distribution area, thin single sandbody thickness, poor reservoir physical properties, thin effective reservoir thickness, sharp horizontal and/or vertical changes in reservoir properties as well as poor connectivity between different reservoirs. Although outstanding achievements have been acquired in this field, there are still several problems in the evaluation and development of the reservoirs, such as: the relation between seismic attributes and reservoir property parameters is not exclusive, which yields more than one solution in using seismic attributes to predict reservoir parameters; the wave impedance distribution ranges of sandstone and mudstone are overlapped, means it is impossible to distinguish them through the application of post-stack impedance inversion; studies on seismic petrophysics, reservoir geophysical properties, wave reflection models and AVO features have a poor foundation, makes it difficult to recognize the specific differences between tight sandstone and gas-bearing sandstone and their distribution laws. These are the main reasons causing the low well drilling success rate and poor economic returns, which usually result in ineffective development and utilization of the field. Therefore, it is of great importance to perform studies on identification and prediction of effective reservoirs in low permeable sandstone strata. Taking the 2D and 3D multiwave-multicomponent seismic exploration block in Su6-Su5 area of Sulige field as a study area and He 8 member as target bed, analysis of the target bed sedimentary characteristics and logging data properties are performed, while criteria to identify effective reservoirs are determined. Then, techniques and technologies such as pre-stack seismic information (AVO, elastic impedance, wave-let absorption attenuation) and Gamma inversion, reservoir litological and geophysical properties prediction are used to increase the precision in identifying and predicting effective reservoirs; while P-wave and S-wave impedance, ratio of P/S wave velocities, rock elastic parameters and elastic impedance are used to perform sandstone gas-bearing property identification and gas reservoir thickness prediction. Innovative achievements are summarized as follows: 1. The study of this thesis is the first time that multiwave-multicomponent seismic data are used to identify and predict non-marine classic reservoirs in China. Through the application of multiwave-multicomponents seismic data and integration of both pre-stack and post-stack seismic data, a set of workflows and methods to perform high-precision prediction of effective reservoirs in low permeable sandstone is established systematically. 2. Four key techniques to perform effective reservoir prediction including AVO analysis, pre-stack elastic wave impedance inversion, elastic parameters inversion, and absorption attenuation analysis are developed, utilizing pre-stack seismic data to the utmost and increasing the correct rate for effective reservoir prediction to 83% from the former 67% with routine methods. 3. This thesis summarizes techniques and technologies used in the identification reservoir gas-bearing properties using multiwave-multicomponent seismic data. And for the first time, quantitative analysis on reservoir fluids such as oil, gas, and/or water are carried out, and characteristic lithology prediction techniques through the integration of pre-stack and post-stack seismic prediction techniques, common seismic inversion and rock elastic parameters inversion, as well as P-wave inversion and converted wave inversion is put forward, further increasing the correct rate of effective reservoir prediction in this area to 90%. 4. Ten seismic attribute parameters are selected in the 3D multi-wave area to perform a comprehensive evaluation on effective reservoirs using weighted-factor method. The results show that the first class effective reservoir covers an area of 10.08% of the study area, while the second and the third class reservoirs take 43.8% and 46% respectively, sharply increasing the success rate for appraisal and development wells.

藏东南巨厚松散堆积体发育条件、成灾模式及防治对策——以川藏公路然乌至鲁朗段为例

The unique geologic, geomorphic and climatic conditions of southeast Tibet have made the region to develop the multi-style and frequently occurring geologic hazards, especially the collapses and landslides and debris flows along the section of Ranwu-Lulang in Sichuan-Tibet highway. However, most of those geologic hazards have close relationship with the loose accumulations. That is, the loose accumulations are the main carrier of most geologic hazards. Thereof, the huge-thick accumulations along the highway is regarded as the objective in the thesis to study the geologic background, hazarding model and mitigation methods comprehensively, based on the multi-disciplinary theories and former materials. First of all, in the paper, based on field engineering geologic investigations, the genetic type and the characteristics of spatiotemporal distribution of the huge-thick loose accumulations along the highway, have been analysized from the factors of regional geology and geomorphy and climate, as well as the coupling acting of those factors with inoculation and eruption of the loose accumulations geologic hazards. The huge-thick loose accumulations has complex genetic types and specific regulations of spatiotemporal distribution, closely controlled by the outer environment of the region. The accumulations are composed of earth and boulder, with disorder structure and poor sorting, specific forming environments and depositing conditions. And its physical and mechanic properties are greatly distinguished from rock and common earth inland. When Sichuan-Tibet highway was firstly constructed along the north bank of Purlung Tsangpo River, the huge-thick loose accumulations was cut into many high and steep slopes. Through the survey to the cut-slopes and systematic investigation to their failures, the combination of height and angle of the accumulations slope has been obtained. At the same time, the types of genetic structure of those cut-slopes are also analysized and concluded, as well as their failure models. It is studied in the paper that there are piaster, duality, multielement and complexity types in genetic structure, and rip-dump-repose, rip-shear-slip and weathering-flake types in failure models. Moreover, it is briefly introduced present engineering performance methods and techniques dealing with the deformation and failure of the accumulations cut-slope. It is also suggested that several new techniques of slope enforcement and the method of landslide and rockfall avoiding should be applied. The research of high and steep cut-slope along the highway has broadened the acknowledgement of the combination of cut-slope height and angle. Especially, the dissertation also has made the monographic studies about the geologic background and hazarding models and prevention methods of some classic but difficult accumulations geologic hazards. They are: (1) Research of the engineering geologic background of the 102 landslide group and key problems about the project of tunnel. The 102 landslide group is a famous accumulational one composed of glacial tills and glaciofuvial deposit. The tunnel project is a feasible and optional one which can solve the present plight of “sliding after just harnessing” in the 102 section. Based on the glacial geomorphy and its depositing character, distribution of seepage line, a few drillhole materials and some surveying data, the position of contact surface between gneiss and accumulations has been recognized, and the retreating velocities of three different time scales (short, medium and long term) have been approximately calculated, and the weathering thickness of gneiss has also been estimated in the paper. On the basis of above acknowledgement, new engineering geomechnic mode is established. Numerical analysis about the stability of the No.2 landslide is done by way of FLAC program, which supplies the conclusion that the landslide there develops periodically. Thereof, 4 projects of tunnel going through the landslide have been put forwards. Safety distance of the tunnel from clinohefron has been numerically analysized. (2) Research of the geologic setting and disaster model and hazard mitigation of sliding-sand-slope. From the geologic setting of talus cone, it is indicated that the sliding-sand-slope is the process of the re-transportation and re-deposit of sand under the gravity action and from the talus cone. It is the failure of the talus cone essentially. The layering structure of the sliding-sand-slope is discovered. The models of movement and failure of the sliding-sand-slope has been put forwards. The technique, “abamurus+grass-bush fence+degradable culture pan”, is suggested to enforcement and green the sliding-sand-slope. (3) Characteristics and hazarding model and disaster mitigation of debris flow. The sources of solid material of three oversize debris flows have been analysized. It is found that a large amount of moraine existing in the glacial valley and large landslide dam-break are the two important features for oversize debris flow to be taken place. The disaster models of oversize and common debris flows have been generalized respectively. The former model better interpret the event of the Yigong super-large landslide-dam breaking. The features of common debris flow along the highway section, scouring and silting and burying and impacting, are formulated carefully. It is suggested that check dam is a better engineering structure to prevent valley from steeply scouring by debris flow. Moreover, the function of check dam in enforcing the slope is numerically calculated by FLAC program. (4) Songzong ancient ice-dammed lake and its slope stability. The lacustrine profile in Songzong landslide, more than 88 meters thick, is carefully described and measured. The Optical Simulated Luminescence (OSL) ages in the bottom and top of the silty clay layer are 22.5±3.3 kaB.P., 16.1±1.7 kaB.P., respectively. It is indicated by the ages that the lacustrine deposits formed during the Last Glacial Maximum ranging from 25ka B.P. to 15ka B.P. The special characteristics of the lacustrine sediment and the ancient lake line in Songzong basin indicated that the lacustrine sediment is related to the blocking of the Purlung Tsangpo River by the glacier in Last Glacial Maximum from Dongqu valley. The characteristics of the lacustrine profile also indicate that the Songzong ice-dammed lake might run through the Last Glacial Maximum. Two dimensional numerical modeling and analysis are done to simulate the slope stability under the conditions of nature and earthquake by FLAC program. The factor of safety of the lacusrtine slope is 1.04, but it will take place horizontal flow under earthquake activity due to the liquefaction of the 18.33 m silt layer. The realign to prevent the road from landslide is suggested.

青藏高原横波速度与各向异性结构及其壳幔形变印迹

As the most spectacular and youngest case of continental collision on the Earth, to investigate the crust and mantle of Tibetan plateau, and then to reveal its characters of structure and deformation, are most important to understand its deformation mechanism and deep process. A great number of surface wave data were initially collected from events occurred between 1980 and 2002, which were recorded by 13 broadband digital stations in Eurasia and India. Up to 1,525 source-station Rayleigh waveforms and 1,464 Love wave trains were analysed to obtain group velocity dispersions, accompanying with the detail and quantitative assessment of the fitness of the classic Ray Theory, errors from focal and measurements. Assuming the model region covered by a mesh of 2ox2o-sized grid-cells, we have used the damped least-squares approach and the SVD to carry out tomographic inversion, SV- and SH-wave velocity images of the crust and upper mantle beneath the Tibetan Plateau and surroundings are obtained, and then the radial anisotropy is computed from the Love-Rayleigh discrepancy. The main results demonstrate that follows, a) The Moho beneath the Tibetan Plateau presents an undulating shape that lies between 65 and 74 km, and a clear correlation between the elevations of the plateau and the Moho topography suggests that at least a great part of the highly raised plateau is isostatically compensated. b) The lithospheric root presents a depth that can be substantiated at ~140 km (Qiangtang Block) and exceptionally at ~180 km (Lhasa Block), and exhibits laterally varying fast velocity between 4.6 and 4.7 km/s, even ~4.8 km/s under northern Lhasa Block and Qiangtang Block, which may be correlated with the presence of a shield-like upper mantle beneath the Tibetan Plateau and therefore looked as one of the geophysical tests confirming the underthrusting of India, whose leading edge might have exceeded the Bangong-Nujiang Suture, even the Jinsha Suture. c) The asthenosphere is depicted by a low velocity channel at depths between 140 and 220 km with negative velocity gradient and velocities as low as 4.2 km/s; d) Areas in which transverse radial anisotropy is in excess of ~4% and 6% on the average anisotropy are found in the crust and upper mantle underlying most of the Plateau, and up to 8% in some places. The strength, spatial configuration and sign of radial anisotropy seem to indicate the existence of a regime of horizontal compressive forces in the frame of the convergent orogen at the same time that laterally varying lithospheric rheology and a differential movement as regards the compressive driving forces. e) Slow-velocity anomalies of 12% or more in southern Tibet and the eastern edge of the Plateau support the idea of a mechanically weak middle-to-lower crust and the existence of crustal flow in Tibet.

利用台阵面波资料研究华北克拉通北缘燕山褶皱带及其邻区的地壳与上地幔结构

The continent of eastern China, especially the North China Craton (NCC), has endured intensive tectonic renovation during Mesozoic and Cenozoic, with the presence of widespread magmatism, high heat flow and development of large sedimentary basins and mountain ranges. The cratonic lithosphere of the region has been destroyed remarkably, which is characterized by not only a significant reduction in thickness but also complex modifications in physical and chemical properties of the lithosphere. As for the tectonic regime controlling the evolution of the NCC, various models have been put forward, including the impingement of mantle plumes (“mushroom cloud” model), the collision of south China block and north China block, the subduction of the Pacific plate, etc. Lithosphere delamination and thermal erosion were proposed as the two end-member mechanisms of the lithospheric thinning. However, given the paucity of the data, deep structural evidence is currently still scarce for distinguishing and testifying these models. To better understand the deep structure of the NCC, from 2000 to the present, temporary seismic array observations have been conducted in the NCC by the Seismological Laboratory of the Institute of the Geology and Geophysics, Chinese Academy of Sciences under the North China Interior Structure Project (NCISP). Many arrays extend from the North China Craton and the off-craton regions, and traverse a lot of main tectonic boundaries. A total of more than 300 broadband seismic stations have been deployed along several profiles that traversed the major tectonic units within the craton’s interior, at the boundary areas and in the neighboring off-craton regions. These stations recorded abundant high-quality data, which provides an unprecedented opportunity for us to unravel the deep structural features of the NCC using seismological methods. Among all the seismological methods, the surface wave method appears to be an efficient and widely adopted technique in studying the crustal and upper mantle structures. In particular, it can provide the absolute values of S-wave velocity that are difficult to obtain with other methods. Benefiting from the deployment of dense seismic arrays, progresses have been made in improving the spatial resolution of surface wave imaging, which makes it possible to resolve the fine-scale velocity structures of the crust and upper mantle based on surface wave analysis. Meanwhile, the differences in the S-wave velocities derived from Rayleigh and Love wave data can provide information on the radial anisotropy beneath the seismic arrays. In this thesis, using the NCISP-III broadband data and based on phase velocity dispersion analysis and inversion of fundamental mode Rayleigh and Love waves, I investigated the lateral variations in the S-wave velocity structure of the crust and uppermost mantle beneath the Yanshan Belt and adjacent regions at the northeastern boundary of the NCC. Based on the constructed structural images, I discussed possible deep processes of the craton destruction in the study region.

利用接收函数方位变化研究地壳各向异性

Because of its sensitivity to the velocity discontinuity of the earth, receiver function technique has become a routine procedure used to probe interior structure of the earth. Receiver functions contain anisotropic information of the earth’s interior, however, traditional receiver function techniques such as migration imaging and waveform inversion method, which are based on isotropic media assumption, can not effectively extract the anisotropy information contained in the azimuth variation pattern. Only by using the anisotropic media, e.g. a model with symmetric axis of arbitrary orientation, computing the response, can we obtain the detailed anisotropy information hidden in the radial and transversal receiver function. Focusing on the receiver function variation pattern changing wtih different back azimuths, we introduced different kinds of symmetric systems of seismic anisotropy used often, and summarized some possible causes of anisotropy formation. We show details about how to calculate the response of a stratified anisotropy model with symmetric axis of arbitrary orientation. We also simulated receiver functions among different models and analyzed how the changing of anisotropic parameters influence the azimuth variation pattern of receiver functions. The anisotropy study by receiver function analysis was applied to Taihang Mountain Range (TMR) in North China in this thesis. The maximum entropy spectrum deconvolution technique was used to extract radial and transversal receiver functions from the waveforms of 20 portable seismic stations deployed in TMR. Considering the signal-to-noise ratio and the azimuth coverage, we got the variation pattern of receiver functions for 11 stations. After carefully analyzing the pattern of the receiver functions that we got, we obtained the reliable evidence on the existence of anisotropy in the shallow crust in TMR. Our results show that, although the thickness of the upper crustal layer is only about 1 km, the layer shows a strong anisotropy with magnitude of 8~15%; in the deeper of crust, the magnitudes of anisotropy is about 3%~5%, showing a pattern with fast-symmetric-axis. The crust anisotropy beneath TMR in North China obtained in this study also shows a significant difference in both the lateral and vertical scale, which might imply a regional anisotropy characteristic in the studied region.

地震资料叠前储层预测综合研究--以辽中凹陷东二下段浊积扇气藏为例

Reservoir prediction techniques from prestack seismic are among the most important ones for exploration of lithologic hydrocarbon reservoir. In this paper, we set the turbidite fan sandstone reservoir in Liao-Zhong depress as our researching target, and aims to solve the apllication difficulties on pre-stack inversion in the area, where the drilling data is scarce and the reservoir is lateral varied. Meanwhile, AVO analysis and pre-stack inversion for gas-bearing detection is systematically researched. The seismic reflection characters of gas-bearing sandstone in turbidite fan with different fluid content are defined, after analyzing results from AVO seismic simulation and porous fluid replacement of real log data, and under the guides of the seismic characters from classical gas-bearing sandstone reservoir and numerical simulation for complicate gas-bearing sandstone. It is confirmed that detecting gas-bearing sandstone in turbidite fan via AVO technologies is feasible. In terms of AVO analysis, two AVO characters, fluid detection factor and product of intercept and gradient, can effectively identify top and bottom boundaries and lateral range of tuibidite gas sand by comparing real drilling data. Cross-plotting of near and far angle stack data could avoid the correlation existing in P-G analysis. After comparing the acoustic impedance inversions with routine stacked data and AVO intercept, impedance derived from AVO intercept attribute could reduce the acoustic impedance estimating error which is caused by AVO. On the aspect of elastic impedance inversion, the AVO information in the pre-stack gathers is properly reserved by creating partial angle stack data. By the far angle elastic impedance alone, the gas sand, with abnormally low range of values, can be identified from the background rocks. The boundary of gas sand can also be clearly determined by cross-plotting of near and far angle elastic impedances. The accuracy of far angle elastic impedance is very sensitive to the parameter K, and by taking the statistical average of Vp/Vs on the targeted section in key wells, the accuracy of low frequency trends is gurranteed; the intensive absorsion within the area of the gas sand, which tends to push the spectral of seismic data to the lower end, will cause errors on the inversion result of elastic impedance. The solution is to confine the inversion on the interested area by improving the wavelet. On the aspect of prestack AVA simultaneous inversion, the constraint of local rock-physical trends between velocities of P-wave、S-wave and density successfully removes the instability of inversion, thus improves the precision of the resulting elastic parameters. Plenty of data on rock properties are derived via AVO analysis and prestack seismic data inversion. Based on them, the fluid anomaly is analysized and lithological interpretation are conducted. The distribution of gas sand can be consistently determined via various of ways, such as cross-plotting of P and G attributes, near and far partial angle stack data, near and far angle elastic impedances, λρ and Vp/Vs, etc. The shear modulo and density are also reliable enough to be used for lithological interpretation. We successfully applied the AVO analysis and pre-stack inversion techniques to gas detecting for turbidite fan sand reservoir in Liao-Zhong depression.

The experimental studies on electrical conductivities and P-wave velocities of anorthosite at high pressure and high temperature

National Science Foundation of China (No. 10032040 and No. 49874013) and Joint Earthquake Science Foundation of China (No. 101119).