Dongting Lake Basin has the conditions for forming biogenic gas reservoirs of certain scales. For the exploration of biogenic gas resources, the authors carried out a comprehensive exploration work mainly based on geochemical methods during the period of 2013~2016, and conducted fairly systematic surface sediments survey. Geochemical exploration covered an area of 2060 km², and collected 1498 samples. All the samples were tested by in situ headspace gas (free hydrocarbon), indoor acidolysis hydrocarbon and a small quantity of methane isotope indexes. The results are as follows: 1. The geochemical anomaly of methane in the Dongting Lake basin is composed of free hydrocarbon (headspace gas) and adsorbed hydrocarbon (acid hydrolysis hydrocarbon). The free hydrocarbon is a dynamic reflection of the existing underground biogenic gas, and the hydrocarbon accumulation of the acidolysis hydrocarbon is related to the distribution of the paleo-channel. 2. The Dongting Lake basin is the area of a high background and high anomaly of methane, and the distribution of the abnormal area is basically consistent with the distribution of the Quaternary fault basin, especially in Yuanjiang sag. 3. Acidolysis hydrocarbon anomaly of the Heba Town, bead-like anomaly in NE direction and southeastern secondary local anomalies form a ring anomaly zone surrounding the Yuanjiang sag, which means that the sag may be the potential supply area of biogenic gas in Dongting Lake basin. 4. The area of Qingshuzuie-Heba Town north of Yuanjiang sag is the abnormal high value area of the hydrocarbon methane in Dongting Lake Basin, and this is the direct reflection of natural gas seepage in shallow surface. The high value of acidolysis hydrocarbon methane surrounds the anomaly area of free hydrocarbon methane in Qingshuzui, which constitutes the best combinational hydrocarbon reservoir model. The area of Qingshui-Haba Town is the 'chimney' of the biogenic gas underlying the Dongting Lake Basin and hence the most hopeful breakthrough area for biogas survey in the Dongting Lake Basin.

The Shanghuangqi-Wulonggou faulted belt is an important tectonic-magmatic-metallogenic belt in North China. Based on 1:250000 stream sediment geochemical survey in Weixian Sheet of Hebei Province, the authors obtained content data of 39 kinds of elements for factor analysis, and made an analysis of stream sediment geochemical anomalies in Zoumayi-Dahenan area along Shanghuangqi-Wulonggou faulted belt. The three geochemical anomaly series of Mo-W-Bi-Cu, Pb-Zn-Ag-Cd and Au-Hg-Agshow very intimate relationship with regional structure, magmatic rocks and metallogenic process. The results obtained by the authors effectively solve the problem of the difficulty in determining element association and spatial distribution of the anomaly due to the superimposition of various elements and hence can provide reference for arrangement of geochemcial exploration and study of regional metallogenic regularity.

Hydrocarbons in the oil/gas accumulations can seep vertically along the pores, joints, microfractures, fractures, and faults to the surface and form geochemical anomalies, which is the theoretical basis of surface geochemical exploration technique. Most of faults underground have big inclination angle, and are not vertically distributed. It is thought that faults are the dominant pathways for microseepage, the geochemical anomalies formed through faults may deviate from the vertical projection of actual hydrocarbon accumulation on the surface. Such a point of view will arouse doubt among geologists about the role of surface geochemistry exploration technique in predicting hydrocarbon accumulations underground. Based on a theoretical model of fault block hydrocarbon accumulation, the authors developed an experimental apparatus to simulate the phenomena of hydrocarbon microseepage of the fault block hydrocarbon accumulations. The effect of faults on vertical hydrocarbon microseepage was studied. The results of the simulation experiments show that faults are not the only dominant pathways of hydrocarbon microseepage from the fault block hydrocarbon accumulations, the fractures and micro-fractures system developed widely in the strata are also the important factors to decide the distribution of surface geochemical anomalies, and vertical hydrocarbon microseepage exists objectively. Whether faults are the dominant pathways of hydrocarbon microseepage or not depends on the sealing capability of faults. The study also shows that the sampling method which is most suitable for delineating the oil and gas target is the highest density grid.

The Taoxi lead zinc ore deposit is located neighboring the central area of gold polymetallic deposit integrated exploration area of Xiuning-Shexian County in Anhui Province, and it is provided with favorable metallogenic geological conditions. The Taoxi lead zinc ore deposit is controlled by the EW-trending fault with mutiperiodic activity features, and tensional normal fault of the third stage is closely related to the lead-zinc mineralization. The lead-zinc ore deposit was formed by cavity filling through migration of ore fluids into fissure zones, and the orebodies exhibit vein-like form. The geochemical composite anomaly of AP18 obtained by soil geochemical exploration is oval-shaped with EW-trending long axis, and it is controlled by the fault. The geochemical anomaly consists of multielements such as Au, Ag, Cu, Pn and Zn, and its area is 2.6105 km². The geophysical anomalies of M2 and M3 were detected by high precision magnetic method, and they are consistent with geological features and geochemical anomaly. The results of IP intermediate gradient and IP sounding prove the actual existence of the anomaly, and also reveal the polarization body characteristics in subsurface. Through comprehensive analysis of geological features and geochemical and geophysical characteristics of the Taoxi area, the authors hold that the area has further ore-prospecting potential for polymetallic deposits.

The high precision airborne geophysical survey can symmetrically obtain high quality multi-parameter geophysical data under the complex terrain conditions at the same time.Two important contents of it are the interpretation of lithostructural mapping and mineral resources prospect.The achievements constitute important geophysical data for basic geological research and regional metallogenic prospective prediction.In this paper,using the new high precision aeromagnetic and airborne gamma energy spectrum data obtained from southeast Hunan,the author gives a systematical description of the process and achievement of the lithostructural mapping and prospecting prediction using the data.The above results can not only directly guide the prospecting work but also serve the relevant geological topics in the future.The comprehensive study shows that the high precision aerial geophysical survey can still play an important role in the area with relatively high geological survey.

The Nihe iron deposit is a typical porphyrite type iron deposit with large burial depth,small amplitude of gravity and magnetic anomalies generated at the surface in Anhui Province. The authors selected the Nihe iron deposit to carry out gravity and magnetic inversion experiment based on known information constraint, in order to evaluate the application effect of gravity and magnetic data fine-grained and three-dimensional inversion in magnetite deep exploration: First of all, through the model test, the authors compared the three-dimensional inversion results with different known information constraints, and then extracted the residual gravity and magnetic anomalies of the Nihe iron deposit through the targeted field separation method. Then, the authors transformed the known surface geological information into physical information, and built a remnant density and magnetic susceptibility reference model to constrain gravity and magnetic three-dimensional inversion. Based on the three-dimensional distribution model of inversion density and magnetic susceptibility body, the authors confirmed the three-dimensional spatial shape of the Nihe iron orebody, and found that the result is basically consistent with geological exploration results. According to the results, the reliability of the inversion results based on the known information constrained gravity and magnetic three-dimensional inversion could be improved. For magnetite with high magnetic and high density, this method is an effective method to find and characterize deep magnetite orebody.

In order to prevent geological disasters and improve urban planning, it is of great significance to explore the distribution of hidden structures in Zhenzhou and its surrounding areas by audio magnetotellurics (AMT). In this paper, an EW-trending AMT profile was set up on the east of Laoyachen fault in the northern suburb of Zhenzhou. Noise reduction, rotation, impedance analysis and static correction of the original data were processed. The 2D regularization inversion theory method, i.e., nonlinear conjugate gradient method (NLCG) was used. The initial mode was constrained by seismic layering results, which was nearly in parallel with the AMT profile, which reduced the multiple solution and the NLCG's dependence on the initial mode. Good electrical results were obtained, which show that there are three layers and a hidden structure in the profile. At the same time, combined with geological and geophysical data, the authors inferred the explanation. It is inferred that the hidden structure may be a normal fault developed in Late Neogene or an unconformable contact surface between Quaternary and Neogene strata. The results obtained by the authors provide the geophysical and technical basis for further exploration of urban hidden structure.

Wushan area in northeastern Chongqing is an important prospective area for shale gas exploration; nevertheless, the exploration degree of this area is low. In this study, based on rock physics and well logging data, the authors used the wide area electromagnetic method to evaluate the favorable area of shale gas in this area. Through the analysis of the surface sample and borehole resistivity logging data, the authors detected that the resistivity of the target layer with rich organic shale in the study area exhibits obvious characteristics of low resistivity, and the features of overlying and underlying layers are significantly different, suggesting that the upper Ordovician Wufeng-Lower Silurian Longmaxi Formation with rich organic matter shale has the physical conditions for electrical prospecting. Based on processing and interpretation of electromagnetic data, the authors found out the structural pattern of "uplift and depression" in Wushan area of Chongqing. The main fault is reverse fault. Ordovician Wufeng-Lower Silurian Longmaxi organic rich shale exhibits characteristics of continuously stable distribution and low resistance, with the depth in the range of 800~4800 m. Considering the resistivity, polarizability and burial depth of the target layer, the authors predicted three favorable areas of shale gas. The organic shale is well developed in this area, and the prospect of shale gas exploration is good.

About 34 papers are chosen and analyzed from the 85^th SEG technical presentations,of which,some are about rock physics and basic theories of anisotropy,some present plausible applications and case studies,some about key techniques on processing,interpretation and inversion of multi-component and multi-wave.Special emphasizes are given to the papers that might proceed the knowledge of anisotropy and principle models,or make progress on key technique of multi-component seismic data processing,besides ocean 4-C seismic and vector techniques.Effected by the lower price of oil worldwide through years,it is obviously that the most advances are about PS-statics correction,dual sensors denoising and 4C application in marine field, though papers about reverse time migration and full wave inversion still occupy a certain ratio,just because they had been the main roles in the past years.It would be predicted that,promoted by sensing techniques and seismic applications,joint application of micro- and time-lapse seismic prospecting based on multi-component,acquirement of seismic and electromagnetic data at the same position,and 6-component seismic measurement and utilization will be the spot lights in the future.

The fracture is the main flow channel and the important reservoir space of the Jurassic tight oil reservoir in central Sichuan Basin,which controls the distribution and the high yield of oil and gas.The fractures of reservoir are mainly divided into the structural fractures formed by the tectonic stress field and the diagenetic fractures produced in the process of reservoir sedimentation and diagenesis.So the study and prediction of fractures is very important for the search of tight oil reservoir.Based on the study of the characteristics and manufacture methods of complex fracture,the authors constructed a fractured reservoir seismic physical model associated with the actual geological parameters,and carried out the study of three-dimensional seismic acquisition of seismic data,the regular pre- and post-stack processing,a 3D P-wave seismic data based on the establishment of a comprehensive crack model.The results have important guiding significance for the study of the seismic reflection characteristics of the fracture and the fracture zone and the investigation of sensitive properties of the optimal fracture prediction.

Taking Qintong sag of Subei basin in lower Yangtze area as the demonstration area, the authors investigated the evaluation of shale gas resources with the artificial intelligence method. With the combination algorithm designs, the authors conducted the whole process of demonstration operation based on continental shale gas resources evaluation parameters of the work area. First, Qintong sag was divided into 14 sample areas by the method of deformation structure partition; then, using the fuzzy mathematics method, the authors obtained quantitative and half-quantitative parameter values; after that, using factor analysis method the authors conducted the evaluation of 14 sample areas in a single plane; finally, composite evaluation of five shale gas layers in vertical direction of 14 sample areas was made based on the evaluation of 5 single planes. In order to get the equivalence data of each single layer, the authors introduced the zero value and grading values. The practise of the combination algorithm designs has the reference value for the shale gas resources evaluation system of artificial intelligence.

Altimetry based gravity anomaly has poor resolution and relatively smooth effectiveness,which results in difficulty in obtaining local short-wavelength information.It is necessary to fuse altimetry based gravity anomaly with shipborne based gravity anomaly,which has higher accuracy and contains more short-wavelength information than the altimetry based gravity anomaly,and to study the method of multi-source gravity fusion so as to improve the accuracy of gravity anomaly field.In this paper,a kind of multi-source gravity field fusion method based on wavelet analysis was proposed;the authors designed different fusion strategies for different frequency coefficients and also discussed the differences of the fusion results when they are based on different wavelet functions.The proposed method was applied to the northern margin of the South China Sea.The fusion result contains more accurate short-wavelength anomalies than the altimetry-based gravity anomalies along ship tracks,and it also has more accurate long wavelength characteristics than the ship borne gravity anomalies between shiptracks.

1:50000 geochemical survey has been completed in the northern part of Chongli District, Zhangjiakou City.The position of Xiaoxiwan intrusive rocks is highly consistent with the Xiaoxiwan composite anomaly (AS33) delineated by geochemical exploration. Utilizing regional data and large scale geological, geophysical and geochemical data obtained by anomaly verification, the authors made an integrated analysis of the ore-forming conditions of this district, and inferred the formation mechanism of mineralization alteration as well as the position of the mineralized altered body. Based on inferring mineralization mechanism and establishing model, the authors hold that the district possesses the potential in search for medium-high temperature hydrothermal polymetallic deposits. Suggestions are also put forward concerning the orientation of further exploration.

The static effect is a commonly-existent technical problem in MT method, and its influence could lead to an unacceptable result of the observation data. According to the distinguishing method, correction method and the data collection system, the authors put forward a spatial-domain topological processing method based on the original data. Through the analysis of the cause and representation of the static effect and the superposition characteristics of electric field components, the authors began with the essence of space sampling and completed the formula for obtaining the topological curve, finally got the observation result with different pole distances at the same site and found out the implicit observation information in the observation system of continuous arrays. According to the analytical result of theoretical model, the authors established the model of all the possible static migrations of the record site with the change of pole distance in different parts of local inhomogeneous body and, in addition, established the basic topological result graphic display and interpretation method including using sites to do pseudo-section processing and using the fixed frequency result of all sites in a profile painting pseudo-planar graph. The authors also compiled the software of topological processing and finished this new method of using topological processing method to analyze the static effect of MT both in theory and in application. The test result proves that the topological processing could improve the quality of data. With this technique, the discrimination of static effect could begin with many aspects, could find out the spatial distribution of the distorted electrical field caused by local inhomogeneous body, and could find out the location and spatial distribution of the local inhomogeneous body, thus providing researchers with real information on the surface electric structure. The topological processing could also get the result of changing arrays, and this means the emerging of a new method for inhibiting interference.

As we know,mobility is one of the key parameters for predicting the gas-bearing properties of low-porosity gas reservoirs.However,how to predict the mobility is always a difficult geophysical problem.In porous viscoelastic medium,the existence of fluid leads to different degrees of seismic wave dispersion and attenuation,and many researches have shown that P-wave dispersion is related to the fluidity of the fluid which is the ratio of permeability to fluid viscosity.Thus,the fluidity can be used to assist the prediction of fluid viscosity and permeability.In this paper,based on Zoeppritz approximate equations expressed in ray-domain by Wang Yanghua,the frequency factor is introduced into AVO analysis,and frequency-dependent AVO expressions is deduced in ray domain.The authors also present a frequency-dependent attributes expression to measure the velocity dispersion and analyze the velocity dispersion characteristics with frequency variation,with the features of velocity dispersion varying with frequency,by using expressions of frequency-dependent attributes.Then,the authors combine the velocity dispersion and fluidity of the fluid.Finally,the authors apply the proposed method to oil and gas detection in lithologic gas reservoir which is characterized by high-temperature,high-pressure in DF district of Yinggehai basin.The application results show that the velocity dispersion can effectively predict the fluidity of fluid and the gas-containing property of the reservoir, and the effectiveness of this method is demonstrated.

TTI qP wave numerical simulation method is more accurate than VTI qP wave numerical simulation method in describing the propagation law of seismic wavefield in anisotropic medium because of considering the dip angle factor.Using the pseudo acoustic wave equation,the authors carried out high order finite difference numerical simulation of the seismic wavefield in the TTI medium in this paper.After improving the distribution of the attenuation function,the authors used the improved perfectly matched layer (PML) boundary control equation to deal with the wavefield boundary and achieved good results.Then the pseudo shear wave in the numerical simulation of pseudo acoustic wave equation was suppressed and the stability problem was analyzed.The numerical simulation of different models prove that the TTI medium pseudo acoustic wave equation is stable and the PML boundary control equations have high reliability and applicability.

In view of the lack of geological investigation and the lack of existing geophysical survey methods on Intertidal zone, the technical research of shallow reflection seismic exploration method is carried out in the tidal flat area of Rudong County, Nantong City, Jiangsu Province. The shallow reflection of seismic detection using hammer source and the natural frequency of 60 Hz detector. Through the experiment, the reasonable parameters of the observation system and the instrument are determined, and the high-precision shallow reflection seismic profile which can clearly reflect the Quaternary geological structure is obtained, and unfavorable factors of the shallow seismic exploration data acquisition in the beach area are summarized, provides empirical advice for carrying out shallow seismic exploration in the beach area. From the shallow seismic profile, the location of the Quaternary bottom interface in the survey area is detected, and the internal layers of the Quaternary is divided, and the hidden faults in the laying range are found out. Found shallow gas in Line laying within the scope, and delineated the distribution of shallow gas along the direction of the line.

The sedimentary microfacies analysis in the deep water with no or less wells is often confronted with the difficulty of low core data,no outcrop,and excessive well spacing.In order to solve these problems,it is necessary to use well-log and seismic data method and detailed seismic reflection characteristics and establish the relationship between seismic microfacies and sedimentary microfacies so as to guide sedimentary microfacies study and predict favorable reservoir distribution.Based on lobes of submarine fan in a deep water oilfield of West Africa,the authors established a microfacies model of three different sedimentary microfacies of the lobes of submarine fan by using the forward method of the seismic response characteristics of the different sedimentary microfacies.The well location suggestion is put forward,and this method is proved to have guiding significance for prediction of lobes of submarine fan in deep water oilfield with less wells.

The frequency dependent reflection coefficient can be obtained by time frequency analysis,based on the AVO theory.Using FAVO (Frequency dependent AVO) inversion technique,the authors obtained the property of velocity dispersion degree.Because of the correlation between the velocity dispersion and pore fluid,the property can be used in fluid detection in the reservoir as an identification factor.In this paper,the authors derived the inversion formula and chose the deep-water sandstone reservoir as the research target.The research on gas sand-body characterization and gas content identification was based on 1D numerical model and 2D real section.The inversion results are well coincident with the drilling results,which shows the effectiveness of the technique in fluid identification of deep-water sandstone reservoirs.

Migration imaging technique is commonly used in reconnaissance beyond tunnel or roadway,of which the important part is the travel time calculation.Because the imaging area approximates the whole underground space,such non-penetrating bodies as tunnels or roadways,holes,and mine goaves have a great influence on the travel time of seismic wave.Therefore,based on Fast Marching method (FMM),the authors developed a new algorithm to calculate the travel time of seismic waves for those complex models including the non-penetrating bodies.In this algorithm,a labeling technique is adopted for non-penetrating bodies,and the ray will automatically avoid and bypass the non-penetrating bodies in narrow band of FMM when a ray approaches them,making the seismic wavefront propagation more realistic.Also,this new algorithm can be applicable to the model for irregular ground surface if the above surface area is regarded as a non-penetrating body.Therefore,the new algorithm can deal with the model with non-penetrating bodies and irregular ground surface simultaneously.Compared with the conventional algorithm,the marked point is the only change of the developed algorithm,which maintains the accuracy and efficiency of FMM.The numerical test results show that the improved algorithm can calculate the travel time accurately,and has strong adaptability and good stability to complex model.

The complex lithology and pore system in volcanic reservoir result in the complex conductive features of the strata.The authors applied the electric conduction model proposed by Herrick and Kennedy to the volcanic reservoir in Wangfu area based on the theory of pore geometry.The parameters of the model were determined with core litho-electric experimental data in the volcanic rocks of Wangfu area,and a new electrical efficiency model suitable for the volcanic reservoir of complex pore structures was established.Using the new model to deal with the actual well data has achieved very good results.

In the earlier period of the development of loop source TEM, circular loop was commonly used to approximately simulate the rectangular loop. In order to study the effect of this approximate calculation, the authors analyzed the bias caused by the approximation of rectangular loop with circular loop in this paper. According to the induced electromotive force formula of circular loop and rectangular loop at arbitrary point inside or outside the loop, the response distribution of the two loops was investigated. The results demonstrate that, at the early stage of diffusive field, large difference is caused by the approximation, while at the late stage, relatively small difference is brought out, which can be explained by the theory of smoke ring. Theoretical modeling indicates that the simulation of rectangular loop by circular loop will bring about some errors and lower the detection precision.

Cascade and sub-band frequency spectrum calculation are two power spectrum calculation methods in magnetotelluric data processing. This paper is based on Welch power spectrum calculation method, and sets the processing parameters under the same conditions, so as to use two spectrum calculation methods to estimate magnetotelluric impedance with simulated data and field data respectively. The results show that, for both the apparent resistivity and the impedance phase, the two power spectrum calculation methods obtain nearly the same results for the simulated data and the field data; nevertheless, the sounding curve with sub-band frequency spectrum calculation method is more continuous and more reasonable than that with cascade method at lower frequency, while at high frequency, the cascade method can get slightly better curves than sub-band frequency spectrum calculation.

The airborne geophysical exploration flying vessel which performs operation in middle and high mountain areas needs plateau adaptability.Through a comparative study of the characteristics of AS350B3 helicopter in such aspects as its taking off condition,maximum flying altitude,maximum endurance and plateau flexibility,the authors put forward the type-choosing principle and flying method of the airborne geophysical exploration flying vessel for low altitude and large scale survey.The practical surveying flying in a certain surveying area of Gansu Province has proved the feasibility of the principle and method put forward by the authors.Analysis shows that AS350B3 helicopter can meet the requirement of airborne geophysical exploration in such areas.

The study of the control of geological background over soil elements could provide a scientific basis for regional soil element geochemical research, planting fertilization and agricultural layout. This paper discusses the influence of the geological background on the content and distribution of Cl, Mn, B, Zn, Cu and Mo by using the grid location and chemical analysis, combined with the GIS technology and the related evaluation standards. According to the results, the values of Mn, Cu and Zn are generally moderate and at rich level in Yubei area; Mo and B element values are moderately high and are significantly higher than the values of the main urban area of Chongqing; Zn element values are significantly higher than the national level. B, Cl, Cu and Mn elements show a high degree of spatial correlation, with structural spatial variation playing a leading role, affected by the geological background. Mo and Zn elements show moderate spatial correlation, influenced jointly by structural factors and stochastic factors. The strata play a dominant role in the distribution of elemental content, and the distribution of soil element content corresponds spatially to the strata. Soil parent rock determines soil elements content level, with the main affecting factor being rock type and the subordinate factor being the geological period of the formation of the rock . These features further explain the impact of strata on soil elements. The influences of soil type on elements are also significant. The content of Mn, Cu, Zn, Mo, B is highest in the limestone soil, and the content of Mo is the lowest in paddy soil. These results indicate that the study of the control of geological background as the dominant factor over soil elements can provide the basis for the study of the planting fertilization and agricultural distribution planning.

Quaternary coverage causes the existence of local low velocity zone in the transverse and longitudinal direction in the near-surface area due to natural or human disturbances.It increases the travel time of effective first arrival wave in seismic imaging method and causes seismic imaging profile to lose the background of relative depth extraction about underground layer and anomalies,leading to mislead the judgement in the interpretation process.Ray tracing can simulate the characteristics of the time field in seismic imaging profile when there exists low zone in the near-surface area.To confirm the feasibility and applicability of using direct travel time to make static correction,the authors changed the offset and the depth of the object layer.The results show that the greater the offset,the more serious the distortion of object reflection layer lineups after static correction;the depth of object layer almost has no effect on the statics when the offset is constant;when the offset and the depth of object layer are constant,the greater velocity difference between low velocity zone and underground media,the greater the amount of excessive static correction.The authors used the cross-correlation method to conduct static correction.The anomaly of the profile after static correction is consistent with the drilling result.The two ways confirm the feasibility and applicability of using travel time difference to conduct static correction of seismic image profiles.

In order to maximize the mine radio wave penetration detection efficiency, the author studied various working modes and, through mathematical analysis, obtained the calculation formula for host walking distance, total detection time, time utilization, calculation formula of walking speed, and maximum length of working face detection in various models. On such a basis, a calculation table for detecting parameters was formed. According to the calculation results of this table, reasonable working mode, emission time and moving time were selected to achieve the maximum detection efficiency.

In order to improve the denoising effect of the current time frequency (TF) method on ground penetrating radar signals, the authors accomplished the denoising in the TF domain by using the spectral decomposition reassignment algorithm. The application of a window function in traditional TF transforms to dividing the signal causes a blurred TF distribution, i.e., TF energies of the signal are distributed around the true instantaneous frequencies, which makes it easier to damage useful information of the signal during denosing if the threshold is inappropriate. The spectral decomposition reassignment algorithm is capable of making energy of the signal more concentrated around the true instantaneous frequencies by relocating TF result of the signal, thus obtaining higher TF resolution and reducing the opportunity of damaging useful information of the signal during denosing. Processing results of both synthetic and real data suggest that the denoising effect of the reassignment method is better than that of traditional TF including Gabor transform methods.