Using the geo-electrochemical exploration method in the Tibetan Plateau, the authors carried out prospecting experimental study an chose a known profile for method effectiveness trial. The tests show that the location of geo-electrochemical anomaly is consistent with the known ore body and that applying geo-electrochemical method to prospecting prognosis is feasible in this kind of areas. Through this research work, the exploration model of the geo-electrochemical method in search for concealed ore deposits was established, and the exploration model for ore-prospecting work in similar geochemical landscape areas was also set up.

The authors carried out the study of geochemical methods for grassland-covered hilly terrains in Dong Ujimqin Banner, Inner Mongolia. The methodological testing of length-grade-horizon and the areal testing of different densities-grades were applied in typical deposits. The conclusions are as follows: The samples at the depth of 20~80 cm can effectively reflect anomalies, and soils at the depth of 40~80 cm are the best sampling media to improve the efficiency. The samples collected 500~3 500 m away from the source area can reflect anomalies. The grade of -120 mesh which is poor in SiO₂ and enriched with metallogenic elements is the effective sampling media for regional and follow-up geochemical survey. A 2 000 km² (at the scale of 1:2 000 000) regional geochemical demonstration reconnaissance was conducted in this landscape, and a comparison with the previous work was carried out. The results indicate that the intensity and boundary of ore-forming element anomalies are clearer and the influence of aeolian sand is minimized in this case. The grade of -120 mesh is the best media for 1:2 000 000 regional geochemical reconnaissance.

Based on a systematic study of sedimentary profile from downstream of the Maoniuping REE deposit, the authors investigated the environmental impact of mine development on fluvial deposits. The results show that the sediment profile can be divided into four stages: 0~10 cm,10~30 cm,30~40 cm and 40~50 cm. The authors determined the depositional age of the sediment profiles by ²¹⁰Pb. The average deposition rate of the river is 0.45 cm/a since 1910. According to the rate of sediment profiles, the deposition can be divided to four stages: The first stage is 1910~1940, whose deposition thickness is about 5 cm and whose average deposition rate is 0.168 cm/a. At this stage the content of K, Na, U, S, Mo, Mn, Pb and F decreased gradually. The second stage is 1940~1990, whose deposition thickness is about 22 cm and whose average deposition rate is 0.44 cm/a. At this stage the shallow 12 cm showed the characteristics of high pH, N, P and organic matter but low K, Na, U, S, Mo, Mn, Pb and F, whereas the deep 10 cm presented the characteristics of high K, Na, U, S, Mo, Mn, Pb and F. The third stage is 1990~1999, whose deposition thickness is about 8 cm and whose average deposition rate is 0.889 cm/a. At this stage there existed the characteristics of high pH, N, P and organic matter but low K, Na, U, S, Mo, Mn, Pb and F. The fourth stage is from 1999 up till now, whose deposition thickness is about 10 cm and whose average deposition rate is 0.909 cm/a. This stage presents the characteristics of low pH, N, P and organic matter but high K, Na, U, S, Mo, Mn, Pb and F.

To verify the effects of soil survey in the area of arid desert landscape in northern Chile, the authors conducted sample size fraction experiment, and the results show that the sampling horizon is B or B＋C soil and the best sampling size fraction is -40 mesh grain size. Through applying the method to soil survey, some Cu, Au and other anomalies were delineated, several new copper ore bodies were found. The centers of the anomalies coincide well with the copper ore bodies. The effect of soil survey is fairly good. Nevertheless, anomaly inspection shows that arid desert landscape is not conducive to the formation of geochemical anomalies, and the role of 1:50,000 soil measurement in controlling the anomaly is limited. It is therefore better to use the large-scale geochemical survey.

Secondary clay minerals formed by basalt alteration are often filled in pores and fractures, resulting in the reduction of reservoir space and reservoir capability and bad reservoir effectiveness. The purpose of this paper is to eliminate the effect of alteration and make the storage evaluation conform to the production capacity. The authors classified the alteration into four grades, i.e., mild alteration, moderate alteration, severe alteration and argillization, then comprehensively analyzed the effectiveness of pores according to microscope image features of melaphyre's pores and the influence of alteration on conventional, imaging and NMR logging data. As the fractures make valuable contributions to reservoir capability of basalt, the fractures effectiveness and reservoir integral permeability were analyzed according to the DSI logging based on the influence of clay minerals on fractures. Finally, comprehensive evaluation of reservoir capability was carried out in combination with reservoir physical parameters and effectiveness analysis of pores and fractures,and the reservoirs were classified into ClassⅠ, Ⅱ and Ⅲ in accord with the production capacities.

The detection of ground fissures was carried out by using the high density resistivity method and radioactive energy spectrum technology in Longting Town of Hancheng City. To achieve the purpose of detecting fissures, the authors used the difference between the resistivity method and the radiological method to deduce ground fissures of this area, delineate the hazard zones, and select a reasonable relocation range. In this area, the ground fissures resulted from the double influence of the NE-trending large-size concealed structural faults and the slope collapses of the river bank. The detection results show that the integrated geophysical methods have the advantages of effectiveness, convenience and rapidness in the detection of ground fissures.

Soil geochemical and geophysical methods were employed to investigate the comprehensive anomalies in the western part of the Qianjinxiang deposit. The results show that Ⅵ anomaly with the biggest scale, highest intensity and multiple concentration center is caused by concealed granite in the deep part which is intimately associated with mineralization. Three amplitude frequency anomaly districts were delineated at the place of Ⅵ anomaly by using the induced polarization method, which could be employed to infer the burial depth and attitude. In combination with the continuous conductivity measurement by using EH4, the authors inferred the burial depth, the attitude of the ore body and the favorable mineralization location. Drilling test revealed a molybdenum ore body with high grade and large thickness. It is thus suggested that Qianjinxiang is a favorable place in search for porphyry Cu-W-Mo deposits, and soil geochemical survey in combination with induced polarization method and EH4 is a useful means for low-cost and high-efficiency exploration in this area.

A number of lithogeochemical surveys indicate the involvement of organic hydrocarbon gas during the lead-zinc ore mineralization in Baifutang region, with the obvious presence of hydrocarbon gas anomalies over the ore bodies. To determine the target region for mineralization and perform metallogenic prognosis for the surrounding areas of the ore bodies, the authors used organic hydrocarbon gas method and comprehensive geochemical method for metallogenic prognosis of lead-zinc ores in Baifutang region. The target area for mineralization in Baifutang region was delineated based on data analysis, which agrees well with hydrocarbon gas halos detected by traditional geochemical methods. This method can make up the shortage of traditional geochemical methods and is of great importance for deep ore prospecting using organic hydrocarbon gas survey in this region.

In order to distinguish anomalies related to uranium deposits from many radiometric survey anomalies caused by such factors as lithology,structure and alteration in granite area,the authors used magnetic survey in search for fractured zones,and utilized radon concentrations of active Carbon survey as well as pit gamma ray spectral survey to recognize deep anomalies related to uranium deposits. It is found that economic uranium ores are included on the dip side of the ore-control fractured zones, as evidenced by drilling verification.

The agricultural production had been difficult in North China and Huang-huai basin because of the severe drought from last winter to this spring. Based on the samples from the developing of deep karst groundwater resources, some laws will be established to reflect the induced polarization anomalies and genesis in the different karst water-rich structure of Taian area. The curves of IP. anomalies in the water-rich structure can be classified into ramp, slow down, low-resistance platform and low-resistance V. The anomalies of IP. cross-section contours of apparent resistivity can be classified into low-resistance step, low-resistance gradient and low-resistance U. In the water-rich areas mainly consisting of caves, IP. anomalies include low apparent resistivity, low vision polarization, low half-life time, low attenuation and low multi-parameter synchronous. In the water-rich areas mainly consisting of fault structures, IP. anomalies have low apparent resistivity and low vision polarization, and show the relevant high half-life time, attenuation maximum value exceptions, apparent resistivity and multi-parameter 'RP' anomalies.

During the ore-prospecting work in the depth and the periphery of a certain lead-zinc ore district in Inner Mongolia, the areal high power IP method was adopted to delineate IP anomalies. In combination with geological data, the exploration based on IP median gradient and IP sounding was conducted at the position of the inferred ore-related anomaly so as to determine the attitude and buried depth of the polarized body. Drilling verification proves the effectiveness of the method.

In order to search for deep oil and gas reservoirs, this paper puts forward the high-power pseudo-random signal IP method using the device of dipole-dipole. An introduction to the method was made together with its way of working. This frequency domain method led to the obtaining of promising results in the northeast of Inner Mongolia. By using the method, deep IP anomaly can be detected rapidly and precisely. This method is therefore very effective in oil and gas exploration.

In order to find an effective means for quick prospecting breakthrough in middle and high mountain areas of West China, which are believed to be the most important mineral exploration areas and replacement bases, China Aero Geophysical Survey and Remote Sensing Center for Land and Resources carried out large-scale aeromagnetic survey in high mountain areas. With high-precision measurements and slow undulating flight in accord with the terrain, qualified raw data were acquired. It was followed by detailed magnetic analysis of rocks, intensive interpretation of anomalies, and fast ground inspection, which made it possible to find a series of metal minerals, thus opening up a new prospect for aeromagnetic survey. According to the test survey and the prospecting effects, the large-scale aeromagnetic method has the advantages of rapidness, high precision, low cost and significant effect in middle and high mountain areas, thus having broad application prospect as well as promotional value in these areas.

For the purpose of accurate judgment of the rock salt horizon in a certain ore district and meeting the requirement of reserve calculation, geophysical well logging method was adopted in rock salt exploration. Practice shows that the well logging method can accurately divide lithologic characters and make up the shortcomings of drill coring. In combination with the analytical results of rock salt samples, the regression analysis theory can be used to obtain the relationship between the rock salt grade and the radioactive intensity and predict the industrial grade of the rock salt. The results obtained by the authors demonstrate that the utilization of the regression analysis to predict the industrial grade of the salt rock is feasible, and the predicted result can meet the requirement of field production and provide useful information for rock salt exploration.

Using both ERDAS IMAGINE 9.1 and MAPGIS 6.7, the authors extracted abnormal surplus gravity slope and magnet slope and, with the help of the known relationships between mineral deposits and the abnormal surplus gravity slopes and magnet slopes, reached the following conclusions: Where the gravity slope is within 62?-73?(the value of the surplus gravity is enlarged by 15 times) and the value of the surplus gravity is within -3-1 m/s², the conditions are favorable for mineralization; in the north, where the magnet slopes are within 40?-50? and 61?-70?, the conditions are favorable for mineralization; in the west, where the magnet slopes are less than 30? and the value of the abnormal magnet is within -40--45 nT, the conditions are favorable for mineralization; in the whole mineral deposit, where the magnet slopes are within 71?-80? and the abnormal value of magnet is less than zero, the conditions are favorable for mineralization. The extracted abnormal surplus gravity slope and the abnormal magnet slope can reflect the favorable ore-forming places in the depth, and thus can play a guiding role in deep ore-prospecting work.

Applying the concept of texture analysis in image processing technology to seismic oil and gas exploration, on the one hand, enrich the content of texture analysis, on the other hand, provide a new approach for seismic oil and gas exploration. On the basis of collecting and organizing the relevant literature, this paper summarizes the progress of seismic texture analysis in the following three aspects: ① In terms of the development of the seismic texture analysis, it developed earlier but the application is a little late, especially in the domestic; ② In terms of the algorithm of seismic texture analysis, there are two methods being widely used: the gray level co-occurrence matrix (GLCM) and the texture model regression analysis (TMR); ③ In terms of the application of seismic texture analysis in oil and gas exploration, it is mainly introduced in seismic structural interpretation, seismic facies classification, and prediction of reservoir characteristics. Finally, the author draws the conclusions from the trend of development: with the continuous development of the seismic texture analysis algorithm, the application of the technology will be further expanded in the field of hydrocarbon exploration. Not only in clastic rocks, but also in carbonate rocks and even unconventional oil and gas will be applied. Therefore, it has a very broad development prospects.

The gas-bearing prediction was somewhat verified by frequency differences.The authors mainly probed into the reservoir prediction and hydrocarbon detection in Weixinan region,and described the application of the frequency domain information in detail.In addition,the purpose of reservoir prediction and hydrocarbon detection was fulfilled by summing up the frequency domain characteristics of the drilled water layer and oil layer,and the result has been confirmed in the actual production.

This paper deals with the generalized discrete Shannon convolutional differentiator (GDSCD) for solving seismic velocity-stress equation. The first-order convolution differentiators are provided. An efficient method is proposed to optimize the coefficients of the convolution differentiator. A series of optimal coefficients are obtained for various operator lengths and sampling rates per shortest wave length. The operator accuracy is discussed through filter response. A comparison with various numerical methods and numerical experiments show that the new designed staggered grid convolution differentiator has high accuracy and efficiency for seismic wave modeling.

In order to better attenuate random noise of seismic data and get more accurate seismic data reconstruction, the authors, based on the free surface multiples feedback iteration method, employed multidimensional weighted cross-correlation to replace multidimensional weighted convolution, also known as "the focal transformation method". This method is a whole data driven process in which underground information is not required, especially when the local underground geological bodies are complicated and the information that should be considered is large. In order to improve the traditional effective signal based on the focus of the least square calculation transform whose focus is not centrally concentrated, the authors combined 3D curvelet transform and focal transform and used the L1 norm optimization algorithm to get the solution. The combination of 3D curvelet transform with focal transform random noise attenuation of seismic data can make effective signal more concentrated, and the preservation of effective signal becomes more complete after the removal of the noise signal. In comparison with the interpolation method that only uses curvelet transform or focal transform means, the interpolation experiment used in this paper can reconstruct seismic data more completely and sophistically, and the high frequency information can be preserved effectively.

Microseismic is a useful technique applied to the fluid injecting front image and reservoir dynamic monitoring. The volume of the data is large as a result of continuous monitoring, and the break time of the microseismic events are unknown, and the manual picking will waste a long time, so the microseismic events need be automaticly detected by the computer. In this article, on the base of analysising the characters of background noise and some other correlating noise in the borehole environment are analysised, take long-to-short windows energy ratio as a basic method, combined with polarization analysis, deseign the polary-energy ratio method to detect the microseismic events, and this method is proved useful through the actual data. According to the regular of signal and noise of multi-channels, constrain the result of detection with the differences of arrive time among different geophones. Apply his method to whole set of microseismic monitor data, amount of microseismic events are picked automaticely and stably, got a good application effect.

Wavelet deconvolution is one of the main methods to improve the resolution of seismic data,and the key is the accuracy of the wavelet.Conventional methods usually presume that the wavelet is the minimum phase,but this may not be correct.To solve this problem,the authors utilized the property of the higher order statistic quantity that it includes phase information of the system and suppresses Gaussian noise to study the wavelet extraction method based on cepstrum and, as a result,gave the principles of extracted wavelet based on complex cepstrum,bispectrum and trispectra.In addition the authors constructed a smooth window function to improve the accuracy of wavelet.The method does not need to make any assumption about wavelet's phase,and it can extract wavelet of any phase.Tackling the mixed wavelet,the authors made theoretical experiments to verify the effectiveness of the method,and the results of actual data processing showed the effectiveness of the method.

The porosity of core samples or geological samples plays a great role in the research on ore-forming fluid. Considering the defects of traditional rock porosity measuring or calculating methods which are hardly capable of obtaiing the internal and original information of rock samples, the authors utilized the industrial computed tomography technology to analyze the porosity of core samples, which can intuitively present object density distribution or structure in the form of digital images. Based on CT images of core samples, the authors used modern digital image processing method composed mainly of edge detection and threshold segmentation to carry out measuring and analyzing porosity of core samples from ZK992 well in a certain mining area. The ROI edge of CT images was first detected in the way of wavelet modulus maxima method based on quadric B-spline wavelet, then the ROI of CT images were segmented in the way of an improved Otsu method. The authors not only obtained the porosity values of 10 core samples that range between 1.22% and 5.79% but also drew the conclusion that porosity of core samples increases first and then decreases as sample location becomes deeper. The result of the research shows that the porosity values measured by this method are in accord with the values by experience. This study offers referable value for research on ore-forming fluid and provides a new method or means for measuring and analyzing rock porosity.

In view of the disadvantages existent in the oblique measurement device for measuring magnetic parameters of rock and ore specimens in "Technological Standard for Surface High-Precision Magnetic Survey",this paper studied the feasibility of the leveling testing parameters of rock and ore specimens with the proton magnetometer, derived the calculation method for the magnetic parameters of leveling survey of the rock and ore specimens. The leveling test is simple and reliable, with high measurement accuracy.

In view of the limitation of "profile method" in selecting the profiles, the authors employed the acreage method so as to accurately select the stratigraphic density values in gravity topographic correction. The influence of the stratigraphic density on the gravity value of the whole area was taken into account, and therefore the selected stratigraphic density values are more representative. This method yielded fairly satisfactory gravity topographic correction results in an area of western Sichuan, which reduced the correlation between the gravity after topographic correction and the terrain. The acreage method employs different stratigraphic density values to calculate the measured gravity value again, make topographic correction, get different gravity anomalies, analyze the correlation between the gravity anomaly and the terrain elevation and select the smallest stratigraphic correlation density as the topographic

In the exposed bedrock mountain areas of Guizhou Province, most rocks have very high resistivity, and the greatest difficult met by the large-power electrical prospecting lies in the impossibility of inserting the electrode into the rock, hence the electrode grounding is very difficult or even impossible. In order to improve the grounding conditions and realize large-power electric prospecting, the authors, based on summarizing the traditional method for improving grounding resistivity, have summed up the method and technology for improving grounding conditions in exposed bedrock areas. The method is called "water log drowned sheet electrode method". In this method, the closed water-storage space is built at the electric supply station, a certain height of water is stored in the water-storage space, and the metallic sheet electrode is drowned in the water log, thus improving the grounding resistivity. This method is characterized by large grounding area, good contact condition and stable grounding resistivity. Practice shows that this method can obviously improve grounding resistivity, realize large-power current supply exploration, considerably raise the quality of field data, and achieve good application result.

The relative error formula of the Cagniard resistivity was calculated so as to know the influence of the the location of the antenna laid in CSAMT on the Cagniard resistivity, which was based on the wave zone of the electromagnetic fields in the homogeneous half-space ground caused by the horizontal electric dipole source. In the case of given parameter, three models of the antenna deviations, i.e., horizontal deviation, vertical deviation and comprehensive deviation, were built, and the characteristics of the influence of each model on Cagniard resistivity were discussed. The maximum relative errors of these models on Cagniard resistivity are 170%, 7% and 190% respectively. In addition, the influence of the antenna horizontal deviation of the antenna on Cagniard resistivity is more obvious than that of the vertical deviation.

The radar chart analysis is an application of the phase identification method, which compares standard well log curve with the well logging curves of non-taken coring. It is the interpretation technique to identify lithology and the nature of the oil and gas in unknown wells by curve differences comparative method or area method. This paper describes the principle of the radar chart analysis method and the running process of radar chart drawing software and verifies this method with practical examples. Practice shows that, in log interpretation, the radar chart analysis can accurately determine formation lithology of the well profile and identify the nature of reservoir fluids. With the help of the radar chart drawing program, the comparative analysis of the characteristics of the formation logging response can be well completed.

A new instrument using four-electrode method for electrical measuring of rocks and minerals has been developed. The instrument has very good conductive, non-polarizable electrode device. It can pick up weak signal by using high precision data acquisition system and can measure all kinds of rocks and minerals. Practice proves its high precision, reliability and good repeatability.

The method dealt with in this paper is very suitable for non-stationary nonlinear multi-component signal analysis. This paper discusses the basic principle of EMD, and studies a signal denoising method based on EMD. According to the different feature scales of EMD, the signal is decomposed into different frequency IMF components. Through deleting the high frequency IMF components full of noise and choosing the low frequency or the specified frequency IMF components, the signal can be reconstructed, thus achieving denoising. The results of simulation signal and measured data both show that the method can not only effectively remove the deterministic or random noise but also preserve the effective signal as much as possible and reduce the signal loss, thus improving the accuracy of data processing.

Airborne time-domain electromagnetic(ATEM)system has some advantages, such as high-speed, economy and deep-exploration depth. ATEM is one of effective methods to explore water resources and minerals. Study on the detection resolution of three-dimensional (3-D) geological body has great importance in ATEM detection in China. The article using finite-difference time-domain method (FDTD) and Central loop mode calculates the airborne electromagnetic response of 3-D typical geologic body. We had discussed the detection resolution of 3-D targets which were in different depth or electrical conductance. Combine with the reality operating parameters of ATEM system, and we calculated 3-D anomalous body of 70 m?70 m?70 m. Numerical calculation results indicate that, when the ratio of electrical conductance of abnormal and background is 200, the maximum range of detecting depth is 180 meters. When reasonable improve the magnification of the receiver front-end, you can effectively enhance the exploration depth. When anomalous body is buried 135m depth, can detect the minimum ratio of electrical conductivity of anomalous body and the surrounding rock is 1.5. Using ATEM methods to study 3-D anomalous body's resolution has great guiding significance of the theory in recognition of anomaly and precise processing for electromagnetic data interpretation.

Beamlet transform has obvious effect in extraction of linear and curvilinear features. The seismic coherence slice can be regarded as an image in three-dimensional seismic interpretation. Beamlet transform can identify and extract linear and curvilinear features in the slice. This paper describes the basic principles of the beamlet transform as well as its advantage in linear feature extraction of the noise-containing image. The authors used the beamlet transform to guide the fault interpretation of seismic slice data obtained in Yuanba area of Sichuan. The results show that the method has obvious advantages in interpretation of small faults and fissures.

In order to improve the maintainability and scalability of geophysical software, this paper applies plug-in software architecture to developing Geophysical Software Platform (GeoProbe). Based on a study of plug-in and its key development technology, this paper introduces the design ideas of GeoProbe's plug-in interface and its management and calling mechanisms used in GeoProbe software platform in details. Applying the plug-in technology, the authors developed a new generation of airborne geophysical data processing and interpretation system on the platform, in which the scientific research achievements in the airborne geophysical exploration technology system program (863 major program) were integrated comprehensively. The system mainly includes aeromagnetic survey system, airborne gravity survey system, time-domain airborne electromagnetic survey system and airborne gamma-spectrometric survey system.

The study of soil organic carbon density and its distribution characteristics in Zhangye-Yongchang area can contribute to the investigation of land utilization, carbon sequestration and regional climate change based on the multi-target geochemical survey. According to the analytical results of average soil carbon density at the depth of 0.2 m and 1.8 m in the study area, the average soil organic carbon (SOC) is much lower than the national value. The SOC at 0.2 m in Shandan Army Horse Ranch is the highest while the SOC at 1.8 m in Shandan Army Horse Ranch and Zhangye has the highest value and is higher than the value at 0.2 m, which should be related to the preservation of organic materials in deep soil. The SOC value of chernozem is much higher than that of black soil and boggy soil. The average values of SOC, SIC and SC in gardens are higher than those of grass which has the lowest values. The average value in peneplain is higher than that in middle mountain and wind-blown terrain which has the lowest value. In brief, the soil type, the land utilization type and the landscape/regional geomorphology can influence the soil carbon density and its distribution.

The survey of mine-out collapse disasters in a complex geological environment is the key to the investigation and tackling of mine safety hazards. In order to delineate the spatial distribution of the mine-out area accurately, the authors used ground penetrating radar and transient electromagnetic methods to carry out the field work according to the site geological conditions and environmental influence factors. Based on an analysis of typical abnormal characteristics of cross sections, the authors deduced the scale and burial depth and finally arranged additional drill holes to verify the effectiveness. The result shows that the integrated geophysical methods applied to the shallow mine-out area of gold mine are highly efficient and feasible.

With a tunnel detection example, this paper describes the applications of the TGP206 system in such fields as karst survey, mud-outburst, water-gush and fault. Through the analysis of seismic wave characteristics of such geological diseases as karst, mud-outburst, water-gush and fault, the authors obtained satisfactory results in tunnel detection.