The theoretical dispersion curves based on the assumption of horizontal layered-elastic media is needed to be calculated in the inversion for the conventional multichannel analysis technique of surface waves(MASW).As a result,the horizontal resolution of this method can not meet the requirements of the lateral inhomogeneous complex media.At present,full-waveform inversion technology has become a research hotspot,whose inversion process is based on the solution of wave equation.For Rayleigh waveform inversion,it is unnecessary to calculate the dispersion curves according to the dispersion equation.In theory,it overcomes the 'inborn deficiency' of the conventional MASW method in the lateral resolution ability.Therefore,Rayleigh waveform inversion is an important development direction in Rayleigh wave exploration field.The development history of full waveform inversion is fully reviewed in this paper.And the development status and the existing problems in Rayleigh wave inversion are also analyzed.Furthermore,the problems needed to be studied further and the development trends of Rayleigh wave inversion are pointed out.It provides some research ideas for the study of Rayleigh waveform inversion.The research achievement s have certain reference significance.

The requirements and simple quality evaluation method of solid geochemical sampling are given in China's current norms. In order to more fully reflect sampling requirements, the authors have comprehensively analyzed and discussed the research results of sampling methods and sampling factors in China and abroad. From the two levels of sample and samples, the three dimensions of sample properties, space and time, the sampling compliance, representativeness, pertinence, uniformity and timeliness are used as the index system to measure the quality of solid geochemical sampling, and the representative and pertinent indexes are qualified. The new index has definite practicability for evaluating the quality of field sampling in geochemical sampling.

The geochemical characteristics of stream sediments in the Hanshuiquan area were analyzed. Combined with ore-forming geological conditions, the authors delineated eight anomalies. Based on the investigation in Y1 comprehensive anomaly, the authors delineated three copper mineralization zones which include several copper mineralization bodies. The geochemical prospecting of stream sediments exhibit ideal ore-prospecting effect. Through the combination of comprehensive anomaly analysis and investigation, regional metallogenic and local geological setting, three potential ore-prospecting areas were delineated, which included 868 highland Cu-Au area, western Xianshuiquan Cu-Au area and Xianshuiquan gypsum area. The results obtained by the authors provide reference for the future prospecting.

The survey of pluton distribution is vital to the study of geothermal system. Using the latest gravity, CSAMT, microtremor survey and previous magnetic data, the authors studied the spatial distribution of several plutons in northwest Beijing. The results show that these plutons have different geophysical characteristics, which suggests that they were formed in different intrusive periods and were developed in different tectonic environments. There are thick dolomite strata of Quaternary period and Jixian System between Huata pluton and Gecun pluton in the southwest of the study area, which may be the main flow channel of underground hot water. The intrusive occurrence of Yangfang pluton exhibits gentle slope in the west and steep slope in the east. The distribution of these plutons is controlled by Nankou Mountain front fault, Nankou-Sunhe fault and Yingbishan fault.

The study of the ore-forming environments of sandstone-type uranium,such as strata,folds,fractures and sand bodies,is significant for predicting and evaluating the uranium resource in Wucaiwan area of Junggar Basin.The technology of the two-dimensional seismic exploration was used to detect the ore-forming environment of sandstone-type uranium deposits for the first time and to tackle the problem that the traditional methods have low accuracy in surveying the structures and interpreting the sands in this area.On the basis of the previous methods,the related technology was improved through experimental research,a seismic data acquisition method based on vibroseis for sandstone-type uranium deposits in Junggar Basin was set up,a set of processing flow for the seismic data characteristics in the area was established,and the method for identifying the sand body was founded based on the seismic inversion technique of linear quasi-acoustic reconstruction.On such a basis,the fold morphology of "Shaqiuhe anticline,Lucaogou syncline,Huoshaoshan anticline,Xidagou syncline and Zhangpenggou anticline" in this area was basically ascertained.It is found that there exist ore-controlling fractures in the two wings of the Huoshaoshan anticline,and there exist the developing characteristics of sand bodies in target beds;meanwhile,an ore-forming favorable area was predicted.In conclusion,the established and improved seismic exploration technology for sandstone-type uranium deposits in the Junggar Basin can solve the problem of detecting the metallogenic environment of uranium deposits in this area.

In the course of coalbed methane exploration and development, it is very important to make a more accurate prediction of gas content and its distribution. The authors collected, sorted and analyzed the exploration zone logging as well as coalbed gas test data and used multiple regression analysis method to establish the relationship between logging parameters and coalbed methane (CBM) content, predicted coalbed methane content and its distribution in the whole exploration area. The results show that the calculation of gas content in coal seam by multivariate regression method is fast, accurate, convenient and practical. The distribution trend of coalbed methane content provides reference for selecting favorable areas for coalbed methane exploration and development.

In large-area soil geochemical survey, different geological units have different geochemical backgrounds, forming multiple backgrounds. Geochemical data from different map sheets exhibit deviation caused by sampling methods or analytical methods. This paper aims at leveling the geochemical data from Duobaoshan area of Heilongjiang Province, dividing different geological units into subareas, making normalization processing for data of different subarea, then calculating anomaly contrast based on sampling sites and acquiring element anomalies. In addition,, specification processing can be made for anomaly contrast, and comprehensive anomaly information can be extracted. The above method can effectively reduce background differences and avoid false anomaly. Finally, many gold orebodies were found in the later exploration by the anomaly inspection of certain comprehensive anomalies, which can prove the effectiveness of this method in extracting abnormal information.

The Jiajika lithium deposit is located in the Songpan-Garze orogenic belt of the Tibetan Plateau, lying in the middle part of the central fold-nappe zone of the Yajiang passive continental margin as well as the Yajiang tectonic-magmatic dome-like metamorphic body group. In this paper, the geological-geochemical prospecting model of the Jiajika lithium deposit is summarized, providing a demonstration for the prospecting of the periphery and the same type deposits in the Jiajika orefield. The exposed strata in this area are only Triassic and Quaternary sediments, and the Quaternary cover is more than 80%, which increases the difficulty to explore REE ore deposits. Lithium (Li), beryllium (Be), rubidium (Rb), cesium (Cs) and other rare metal elements possess a relatively small proportion with strong chemical activities, and lithium especially tends to be adsorbed on clay minerals, resulting in increasing lithium content in soil and easily forming secondary halos. By carrying out large-scale geochemical prospecting in subscale soil, the prospecting range can be rapidly reduced and the target areas can be delineated, which plays an important role in the discovery of rare metal deposits.

Along with the strategic shift of uranium prospecting space, the blind exploration of deep penetration becomes the trend of the times. A new geophysical prospecting model with effective combination of exploration techniques and methods of different landscape areas and different ore deposit types has been established, resulting from the application of the new geophysical prospecting model. It is very important to explore the relationship between multi-information in ore-forming prediction. Based on this idea,in the interpretation of ²¹⁰Po anomaly in Erlian Basin, Inner Mongolia, the authors found that there is a close logarithmic correlation between the surface γ exposure rate and ²¹⁰Po. Based on the further analysis of regional geological background data, the possibility of uranium mineralization is predicted objectively.

In order to make use of high precision aeromagnetic data for metallogenic prognosis, it is necessary to extract the weak aeromagnetic anomaly information. Using aeromagnetic enhancement methods (automatic gain control referred to as "AGC") to process high precision aeromagnetic data in and around the Lamasucopper deposit, the authors highlighted the aeromagnetic information caused by weak copper polymetallic anomalies.It is shown that there are many weak anomalies on both sides of the SayramLake, similar to things of the Lamasucopper deposit. It is considered that aeromagnetic augmented processing can extract information of favorable aeromagnetic anomalies, such as copper and gold metallogenic deposits, and can also classify the favorable buried fault structures, so as to provide scientific basis for metallogenic prognosis.

Geological mapping of areas with shallow overburden generally has less bedrock outcrop to work with, and is thus characterized by poor accuracy. Soils formed by weathering of rocks have significant inheritance of chemical composition from the bedrocks. In view of such a situation, the authors propose a soil chemical composition based multi-layer perceptron neural network model to recognize bedrock types. Taking Alongshan area in the northern part of the Da Hinggan Mountains as an example, the authors used geochemical data of major and lithophile trace elements of soil samples overlying volcanic bedrocks to identify bedrock types, and identified 4 types of bedrocks, i.e., basalt, andesite, dacite and rhyolite. The results show that the prediction accuracy of the model in the identification of bedrock types in the shallow overburden area of the Da Hinggan Mountains reaches up to 90%. The authors have reached the conclusion that soil chemical composition based multi-layer perceptron neural network model used for the identification of bedrock types has the advantage of high convenience, high speed and efficiency, and can provide an effective way for improving the geological mapping quality in areas with shallow overburden.

The distribution of groundwater under different hydrogeological conditions has different geophysical responses to various geophysical prospecting methods. Based on the experimental study of geophysical methods, the authors searched for the Quaternary groundwater in the non-uniform water area of the piedmont gobi, used such combinational means as sounding test beside the well, electric resistivity sounding sweeping, sounding of induced polarization detailed investigation and hydrology electric logging, thus achieving a new breakthrough in the search for water. The change of the (ρ_s) parameter of electric resistivity sounding and the (η_s, S_t, Z) parameters of the sounding of induced polarization are closely related to the lithologic structure of the strata and the degree of mineralization of the groundwater and the distribution of geological structures. The parameters of the sounding of induced polarization are more closely related to groundwater richness.

Through practical application, theoretical deduction and simulation calculation, the validity of the frequency selection method of natural electric field in shallow groundwater exploration was illustrated, and the natural field source component which plays a major role in the formation of anomaly was analyzed. The method had been applied to 12th Five-Year Plan of the rural drinking water safety project by No. 273 Geological Party of Guangxi in 2013~2015. According to its exploration results, a total of 131 wells were drilled. 114 wells' water output was more than 1m ³/h, accounting for about 87.0% of the total amount of drill holes. The practical application shows that the frequency selection method is practical and feasible in shallow groundwater exploration. On the basis of practical application and previous research results, a spherical water filled karst model in uniform half space was designed, and the magnitude of the secondary electric field on the main section of the surface was calculated by using analytic method. The calculated results show that the horizontal alternating magnetic field produces a relatively high potential anomaly, whereas the horizontal alternating electric field produces a relatively low potential anomaly. It can be concluded that the formation of anomaly of frequency selection method in groundwater exploration is mainly due to the effect of alternating electric field components.

This study belongs to the aeromagnetic anomaly verification part of the 1∶ 50,000 high precision aeromagnetic survey project in Tengchong-Yunxian area, Yunnan Province. In order to verify some selected aeromagnetic anomalies in the periphery of the Hetaoping Pb-Zn deposit, the authors carried out geological, geophysical and geochemical survey at the abnormal points. The 2.5D human-computer interaction inversion was used to quantitatively analyze the mineralization potential. The prospecting potential of Fe-Cu-Pb-Zn-polymetallic ore in the periphery of Hetaoping Pb-Zn deposit is proved to be huge, which provides the basis for further prospecting. At the same time, it is proved that after the rapid scanning using aerial geophysical prospecting, researchers should carry out high precision ground geophysical, geochemical and geological techniques and other comprehensive verification methods for positioning, distinguishing and evaluating meaningful anomalies, which could be an economical, fast and efficient air-ground combinational survey method.

The dramatic changes of near-surface velocity and vertical as well as lateral thicknesses that result from complicated lithologies and structures in the mountain areas and mountain front of the southern margin of Junggar basin bring great difficulties to the static correction in this area.For the purpose of solving the problem of seismic data imaging in mountain areas,high-frequency time difference between seismic traces must be eliminated to avoid out-of-phase stacking,and medium-long wave length components in static correction must be controlled to ensure the accuracy of the structure location and structural height.The application conditions and adaptability of existing static correction methods were analyzed and studied to improve imaging quality in the mountain areas of the southern margin.A new set of ideas for decomposition and reconstruction of long and short wavelength components were presented according to static correction values,the advantages of different static correction methods could be taken and good effect was obtained in the mountain areas on the southern margin of the Junggar basin.

The typical characteristics of the waterflooded layer are the reduction of oil-gas saturation and the change of conductivity of the mixed formation water. The higher the degree of flooding, the lower the resistivity of the formation water flooded and sewage flooded reservoirs; the resistivity will first decrease and then increase, presenting a "U" or even "S" shape change of freshwater flooded reservoirs. And the changes in the conductivity of mixed formation water will inevitably lead to changes in spontaneous potential, resulting in the abnormal amplitude changes, the abnormal positive and negative inversion, and the baseline shift. On the basis of the typical characteristics of the known flooded layer on the conventional logging curves, a comprehensive analysis of the logging curves can be used to identify the unknown flooded layer, or the logging data can be used to construct a transaction map todetermine the flooded layer.

In geophysical exploration,crack medium is an important potential reservoir medium,and because of its complex structure and characteristics,the detection difficulty of crack medium is always great.For the purpose of identifying and studying the crack medium,it is necessary to conduct exploration and research through geophysical neutron logging method.In this paper,the authors applied the theory of dispersed multi-angle cracks to simulating the water layer strata in the pore-crack medium.The corresponding neutron log data were studied by changing crack parameters.The results of the study show that,in the low and medium angle crack environment,the maximum thermal neutron density is larger than that of approximate horizontal angle crack medium,and its sensitivity is significantly greater than that of other kinds crack environment,and that,in the high angle crack medium,the thermal neutron density map is smooth,indicating that the high angle crack medium has little effect on thermal neutron absorption.In the thermal neutron density distribution plan,the thermal neutron diffusion range is small because of the high hydrogen content in water.By analyzing the water layer thermal neutron density distribution,the maximum density distribution and the maximum time spectrum,the authors found that the neutron in the water layer is more sensitive to low and medium angle crack media,and is easy to be slowed down and absorbed.These results can provide theoretical guidance for geophysical survey work in the field.

Most of shallow seismic signals have low Signal-to-Noise Ratio (SNR) due to the strong surface wave component,which makes is difficult to establish the velocity field.Conventional methods performed poorly in this situation.To overcome this problem,the authors propose a new method based on the adaptive Morlet wavelet and principal component analysis (PCA) process in wavelet coefficients matrix.The difference of horizontal continuity between effective wave and surface wave makes it possible to extract the features in wavelet coefficients domain.Then the reconstructed signal from weighted features presents a high-quality surface wave suppression.Tests on two sets of real data provide a solid evidence for its feasibility in shallow seismic signal.

As one of the measured parameters of the magnetotelluric sounding method, the tipper mainly represents the linear relationship between the vertical magnetic field and the horizontal magnetic field. In this paper, based on the forward modeling of magnetotelluric sounding, the authors derived the formula for calculating the two-dimensional tipper according to the definition of the dump, with emphasis placed on the forward modeling of two-dimensional fault structure model. Compared with the apparent resistivity, it is proved that tipper can more accurately reflect the lateral heterogeneity of dielectric properties. Tipper was successfully applied to the analysis and identification of the fault structure of the measured MT profile.

Reverse time migration based on two-way wave equation is an effective method to deal with steeply dipping structures and complicated velocity models.As a method of wave equation migration,the data required to be input are regularly sampled shot gathers.However,the field acquisition is limited by complex geological conditions and the actual seismic data are usually irregularly and sparsely sampled along the spatial direction,and there is a serious spatial aliasing phenomenon,which affects the accuracy of migration.In this paper,the prestack seismic data regularization technique is proposed for reverse time migration,which is based on the correlation of data in the OVT (Offset Vector Tile) domain to realize the iterative anti-aliasing interpolation for the full wave number band of data.It has the advantages of spectral anti-leakage,anti-aliasing and anti-noise.By mapping the coordinates of the shot gathers from the geometric system,the regularized shot gathers are obtained from OVT domain interpolation results,and applied to the reverse time migration.The application results of real data show that the technology can effectively improve the precision of reverse time migration while saving the cost of acquisition.

In the CSAMT survey, the inductive on transmitting circuit wire increases with the increasing frequency of the transmitting signal. When the power supply voltage and grounding resistance is constant, the transmitting current will drop with the increasing frequency of the transmitting signal, so the received signal in the receiver becomes weak, and the exploration effect is seriously affected. In this paper, by analyzing the impedance characteristics of the transmitting circuit and RCL series resonant circuit and simulating the amplitude and frequency characteristic curve of transmitting circuit which adds the different value compensating capacitors, the authors proved that it is possible to increase the transmitting current of the high frequency signal by adding the different compensation capacitor in the transmitting circuit. On such a basis, the authors designed electrical source CSAMT transmitter based on compensation capacitors technology. Through the high and low frequency signal transmitting, the transmission circuit impedance is determined, then in the transmission process it can be sent with the signal frequency changes and the compensation capacitor is constantly adjusted to achieve effective increase of high frequency band send current. In the working process, first the test method is used to determine the impedance of the transmitting circuit, and then the transmitter will automatically adjust the capacitor compensation network switch with the changing of the frequency of the transmitting signal, the different compensation capacitors are switched into the transmitting circuit to achieve the transmitting current increases. The scheme was tested and verified in practice. The recorded data show that the current in the high frequency area is improved obviously after the compensating capacitor is connected in transmitting circuit. It is expected that this method will enhance the transmitting current of the high frequency area and improve the observation data quality of CSAMT.

Induced polarization is an effective method in exploration of nonferrous metals. Its efficiency is low while the working area including many IP profiles, which is a result of setting up a few of points in one section. In order to improve the efficiency of IP, a new remote electrode gradient device was created by using self-making multi-spacing central gradient device, which is based on Ge Weizhong’s gradient IP and remote electrode. This device can be used as Schlumberger electrode array in small polar distance and central gradient device in large polar distance. The efficiency of IP was improved by using remote electrode from traditional progressive arrangement to array arrangement. It shows the validity of using this IP device in survey of gold ore in complex tectonic and layers area.

Seismic data composite a data carrier of the spatial change relationship,which reflects the characteristics of changes in the geological space.Under the premise of known seismic data,the problem as to how to discover the spatial variation of reservoirs is an important issue in fine reservoir research.Based on the study of the stratigraphic spatial transformation function,this paper proposes a method for obtaining stratigraphic space transformation functions based on seismic trace matching.In this method,multi-channel seismic traces are used to obtain the weighting coefficients,and the multi-point convolution-weighted formation space transformation function is used to replace the point-to-point formation space transformation function,so as to accurately reflect the physical property changes and reduce errors.The actual data of Q oilfield,and the model testing and practical application analysis show that,compared with traditional methods,the proposed method establishes a higher resolution model, contains richer information,and has a high porosity in the distribution of sand bodies.Besides,the distribution of high values is broadly consistent with the distribution of well logging porosity.As a deterministic modeling method driven by seismic information,this method can perform reservoir characterization more accurately and has important significance for geological modeling.

Using some techniques such as computer graphics, human-computer interaction, and topological relation, the authors designed the process about the three-dimensional vector modeling under undulating topography, tetrahedron mesh generation, and hexahedral mesh generation. Through the study, the corresponding software module was developed. In the software, some tetrahedron mesh generation and hexahedral mesh generation utility tools can be provided to solve some related problems in MT. The efficiency of 3D electromagnetic method is improved in such fields as data management, model visualization and interpretation integration.

The study of the effective electrical properties of reservoir rocks can be used to determine the distribution of underground oil and gas storage and identify the oil and water layers. The accurate evaluation of the effective electrical properties of rock models by digital means is of great significance not only forthe theoretical rock physics but also for the development of experimental methods and the application of electrical logging methods. As a new core analysis method, digital rock core technology has gradually become one of the effective methods for studying the effective electrical properties of rocks. Based on the technology of digital core and electromagnetic simulation, the data processing for sample image dataset, the authors carried out the numerical 3D rock model transformation and the computation of the effective electrical properties systematically. Furthermore, four types of rock samples such as sandstone and shale were investigated to discuss the validity and accuracy of the numerical core analysis method. This set of methods for data processing, numerical model conversion and calculation of electromagnetic parameters for scanned core images can be used to efficiently and accurately analyze different types of digital core dielectric constant, conductivity and other properties, which can provide important reference for such fields as rock physics, logging interpretation and reservoir evaluation.

Chengdu-Chongqing region is located in Southwest China, a transition zone between the Se-poor belt in the middle and the Se-high belt in the southeast. The soil geochemical map shows that the Se content of topsoil in Xiushan area of Chongqing is (0.158 ~ 3.14)×10 ^-6, with an average of 0.457×10 ^-6. The soil selenium may come from the underlying black rock series: Niutetang carbonaceous shale of early Cambrian and phytoclastic and organic limestone of middle Permian, both of them might have been deposited among two Paleozoic transgressions. Nevertheless, selenium is deficient in soil of "red layer" in Bazhong and Nanchong, Sichuan. The Se values of topsoil are (0.084 ~ 0.510)×10 ^-6 and (0.033 ~ 0.349)×10 ^-6 respectively, with the average of 0.154×10 ^-6 and 0.140×10 ^-6. That might have been related to the transformation from late Triassic marine environment into Jurassic-Cretaceous continental sedimentary environment, causing selenium deficiency in continental lacustrine sandstone and siltstone.

According to the distribution characteristics of heavy metal elements, nutrient elements (varied quantities of elements for agricultural benefits) and healthy elements in surface obtained from multi-purpose regional geochemical survey in Zhangye-Yongchang area, in combination with features of the landform, soil types and geological characteristics, and with the content grades of pollution elements affecting soil environmental quality (non-pollution, slight pollution, moderate pollution) as the major partitioning basis, the authors divided the whole region into high quality agricultural area, medium quality agricultural area and low quality agricultural area. Among them the high quality agricultural area was further divided into five subareas, which cover an area of 691.83 km ², accounting for 19.66% of the whole surveying area; the medium quality agricultural area was further divided into three subareas, which cover an area of 5 799.49 km ² with widest distribution, accounting for 67.38% of the whole surveying area; the low quality agricultural area was further divided into three subareas, which cover an area of 1 116.10 km ², accounting for 12.96% of the whole surveying area.

Faced with the problems of hydrogeological exploration at the Thousand-Hand Avalokitesvara in Dazu county of Chongqing, this paper adopted ground penetrating radar and drilling electromagnetic wave CT to measure and analyze the rock and soil engineering for the Avalokitesvara, and went on the characteristics analysis and 3D dynamic simulation of main hydrogeological conditions in the region. Results show that nondestructive testing methods of ground penetrating radar and drilling electromagnetic wave CT are good at exploration for cultural relics, such as Thousand-Hand Avalokitesvara. They have many well practical application values.

Geological conditions in Yunnan mountainous area are complex, and geological hazards such as water and mud inrush often occur in tunnel construction. Tunnel geological prediction is an important way to prevent geological disasters in tunnel construction. The rational layout and implementation of advance exploration drilling can effectively reveal the geological conditions in front of the tunnel face and prevent the occurrence of geological disasters. Nevertheless, for the irregular geological bodies such as karst, the limited 1~2 advance exploration drilling holes sometimes fail to reveal these geological bodies and cause major safety risks to the tunnel construction. It is of great significance to make full use of the advanced geophysical prediction data, especially the TEM which can guide the layout of the advance exploration drilling holes and have the great significance for improving the prediction effect. In this paper, taking the Yangwu tunnel of Yumo railway as an example and based on the analysis of TEM, the authors successfully guided the advance exploration drilling layout, and then compared the results with the drilling and construction excavation results. It is shown that the TEM is effective in predicting and guiding the advance exploration drilling. Some suggestions are given concerning the employment of TME combined with advanced horizontal drilling in the future.

In this paper, the high density resistivity method was applied to measure the compactness of grouting in a water reconstruction project in Xiangtan City, and its effectiveness was studied. The abnormal strata were determined according to data processing and image interpretation, and then in combination with the exploration results, the existence of groundwater-rich areas was detected and verified by excavation. The results show that the high density resistivity method has a very good detection effect in the measurement of pipe jacking compactness, and the low-resistivity anomaly area corresponds to the water-bearing undense area.