Narigongma area is located in the alpine landscape region of southern Qinghai Province. Great progress has been made in the prospecting for porphyry deposits, and a series of Cu-Mo deposits or ore spots have been found in this area since the performance of the land and resources survey. The conventional integrated geophysical and geochemical methods have played a significant role in prospecting and exploration. Taking the Narigongma Cu-Mo deposit as a typical example and based on summarizing its characteristic criteria in geology, geophysics and geochemistry, the authors established a geological-geophysical-geochemical comprehensive prospecting model for porphyry Cu-Mo deposits. When the model was applied to periphery prospecting, 12 prospecting targets were delineated. In some of the target areas, a few Cu-Mo spots were found by engineering testing and verification.

Huangzhulin area is located in the southern Ailaoshan metallogenic belt of Yunnan Province, and lies in southwest Yangjiazhai. The lower Permian sandstone, slate and quartz sandstone are main exposed strata. Through soil geochemical profile measurement, a gold anomaly was delineated in Huangzhulin area. The abnormal area has obvious concentration, continuous distribution of high value points, and obvious three-stage zoning. The anomaly is a good composite anomaly with the association of Au-As-Sb-Ag-Mo-Hg and Cu-Pb-Zn. Through the analysis of primary halos of rock samples from Gaojingchao Group, the authors detected the geochemical characteristics of the front halo and near-ore halo of the ductile shear zone type of gold deposit, which has the middle and deep prospecting potential. Based on the geological, mineral resources and geochemical information, the authors present an ore-prospecting model for ductile shear zone type gold and polymetallic deposits in this area.

The Huaishuping gold deposit is a large quartz vein gold deposit recently discovered in the Xionger Mountain of western Henan Province. The mineralization has the characteristics of multiple periods, and determining the gold metallogenic material association and metallogenic period of this ore deposit would be helpful to further development of the geological prospecting work.The multivariate statistical analysis of geochemical data shows that the enrichment of Au is closely related to the elements of Bi, Ag, the main ore-forming stages of Au is consistent with the As-Ag-Hg combination precipitation phase, the Pb-Zn polymetallic sulfide mineralization stage and the Cu-W-Mo combination precipitation phase. As shown by rock and ore appraisal and field survey, the paragenetic association of minerals is (pyrite, hematite)-marcasite- sphalerite-galena-(chalcopyrite, bornite)-digenite, whereas the wall rock alteration assemblage is potassium feldspar,quartz, biotite, kaolin clay, calcite, dolomite, sericite, chlorite, and epidote. The metallogenic period can be divided into alteration period,hydrothermal period and supergene period, whereas the hydrothermal period can be divided into milky-white quartz vein stage,gray quartz-polymetallic sulfide stage, white quartz vein-pyrite veinlet mineralization stage and quartz-carbonatization stage.

In order to study geochemical prospecting effect of sulfur dioxide gas and mercury soil gas in the concealed Cu-Ni deposit in an arid desertification area, the authors designed an experiment of mercury soil gas and sulfur dioxide gas geochemical profile measurement in the Shaquanzi concealed Cu-Ni deposit. The results show that mercury soil gas and sulfur dioxide gas exhibit anomaly characteristics over the concealed mineralization body. It is demonstrated that the two methods are effective in search for the concealed Cu-Ni deposit, and hence the results obtained by the authors provide new prospecting ideas for the prospecting work in the arid desertification area.

The application of constant element geochemical characteristics to the evaluation of ore-bearing properties has important significance. In this paper, the authors found that there is a clear boundary value of the aluminum saturation index between the orebody and the barren body among the 210 intermediate-acid rock bodies in Shanxi Province. Aluminum saturation may be an important indicator to reflect the capability of the intermediate-acid magma for releasing the ore-forming elements. The result obtained by the author is of reference value for evaluating ore-bearing potential of intermediate-acid magma in other areas.

This paper briefly describes the geological background of the Mayang basin in Hunan Province. The density characteristics and Bouguer gravity anomaly characteristics of the Mayang basin were analyzed. In combination with previous research results of seismic data and from the two aspects of gravity and seismic level, the authors emphatically studied the formation mechanism of Mayang gravity high, crystalline basement uplift and Moho uplift. The authors carried out the semi-quantitative inversion of inference and interpretation for Mayang high gravity anomaly. According to the relevant literature, the tectonic evolution characteristics of Mayang basin were analyzed, and the discovery of the deep structure and its ore-controlling significance in Mayang basin were pointed out. In addition, a new idea in search for oil and gas reservoirs in Mayang basin is put forward.

Gas hydrate, an insulated solid with high resistivity, has the basic physical property for electromagnetic exploration. In Muli permafrost area, TEM experiments were performed where gas hydrate samples were acquired by core. In the apparent resistivity pseudo-sections of TEM line, there exist a continuous high resistivity layer in the shallow part and a discontinuous high resistivity layer in the deep part. The shallow high resistivity layer is confirmed as tundra depending on the temperature logging of gas hydrate hole in Muli permafrost. The deep high resistivity layer, which is under the tundra, lies in the gas hydrate stability zone (GHSZ) of Muli area. Its depth corresponds to the depth of gas hydrate-bearing layer in known drill holes. According to the experiment, the preliminary conclusion is that transient electromagnetic method can be used in gas hydrate exploration in permafrost area based on its high resistivity detection capability.

Seismic reflection exploration is the main method of detecting urban active faults at present.The effect of investigating fault is fairly satisfactory in areas with thick Quaternary sediments.Detecting active faults by the seismic method is more difficult because of adopting shorter receive array length,more serious source disturbance to shallow reflection interference,and requiring higher resolution in urban shallow Quaternary sediment areas.Geziwo fault in Beidaihe is part of Qinhuangdao-Dalian fault on land.Because the fault is a hidden fault,the dip,fault distance and upper break point as well as spatial distribution of the fault all show uncertainty. In order to find out the spatial distribution shape,nature and activity of the fault,the author detected the fault by shallow seismic exploration technology with high precision,with the obtaining of a very clear reflection seismic image.The Quaternary internal interface,bedrock and bedrock weathering layer as well as fracture structure can be explained on the basis of the seismic profiles.The seismic detecting result provides the basis for the layout of the drilling joint section,the design of borehole depth and the evaluation of the fault activity.The high-precision combined drilling geological sections show that the main stratigraphic boundaries and fault features obtained from the seismic exploration methods are quite consistent with the results from the composite drilling geological section.

Through the summarization of 75 high density resistivity survey lines and 57 drill holes, the authors studied high density electrical prospecting anomaly of water-bearing structure in karst area of southeast Chongqing. Water-bearing structure in karst area of southeast Chongqing may be divided into three kinds of geological models:corrosion fissure, karst cave and karst conduit, and structural fissure. According to the statistical results of high density electrical prospecting anomaly in karst area of southeast Chongqing, the authors divided them into four groups:low resistance stripe in surface layer, UV type low-resistant anomaly, the paste or cystic low resistance anomaly, and the beaded low resistivity, with each kind of anomaly corresponding to the 1~3 type of water-bearing structure in geological model of the karst area. High density resistivity method is the preferred method for geophysical water exploration in karst areas of southeast Chongqing. The authors summed up the experience of regional exploration and revealed that reasonable interpretation of high density anomaly after the recommendation of drill hole in karst areas can avoid the problem of mudstone filling and increase the well completion ratio.

The aerogeophysical survey method,as one of the effective geophysical exploration technologies,plays an important role in the geological survey of oil and mineral resources,and is also an important technical means for the survey of the land and resources as well as potentiality assessment of mineral resources.This paper gives a comprehensive description of airborne magnetic gradiometer system,airborne electromagnetic system,airborne gamma system and airborne gravity system and their associated equipment techniques as well as indexes and applications.The above discussion shows that the development of aerogeophysical technology is very mature abroad.In China,however,this technique is only at the developing stage.The key technique of the aerogeophysical survey in China remains rather backward in comparison with that of the developed countries.The technology of aerogeophysical survey in China needs rapid development.

For the purpose of exploring the applicability of various devices of high density resistivity method and according to the finite difference method, the authors conducted forward modeling of high and low resistance abnormal body, which included 7 kinds of devices, i.e., secondary arrangement, tertiary arrangement, Wenner device, dipole device, differential device, dipole-dipole device, and schlumberger device. The simulation results show that the effect of the dipole device for detection of low resistivity anomalous body and high resistivity anomalous body is better, the Wenner device is applicable only to the detection of high resistivity of abnormal body and the boundary between high and low abnormal bodies, and the shapes or positions of the high and low abnormal bodies detected by other devices show certain deviations from the actual situation. The simulations were applied to loess cave and karst investigation, and achieved good detection results. The results obtained by the author provide a reference for the investigation in similar work areas.

Based on the first airborne gamma ray spectrometer on the drone in China,this paper briefly described related techniques such as principle,calibration, measurement,and data processing.Through the demonstration surveys in both Karamay and Kashi,rich results of aero radiometric survey were obtained.Combined with regional geology,remote sensing data,radioactivity characteristics of rocks and the results of ground-checking,the authors analyzed and evaluated the regional features and the local anomalies of aero-radiometric survey comprehensively.The results show that the technique is an effective method in such aspects as basic geological investigation and exploration of radioactive and non-radioactive mineral resource.Finally,the measurement technique was evaluated briefly for the drone based on the fix-wing craft.

This paper introduces the development and integration of Unmanned Blimp Aeromagnetic Acquisition System (UBAS).UBAS's platform is an unmanned blimp,which is equipped with excellent flight control,navigation system and high-precision aeromagnetic survey system.So it can implement unmanned operation,three-dimensional autonomous navigation along the designed flight route.Trial and practical application was carried out for UBAS.A comparison with aeromagnetic survey data completed in the past shows highly similar characteristics in the anomaly contour maps,which verifies the effectiveness of the system.The authors also used different scales and flight parameters in this project,and it is shown that UBAS' results highlighted more weak magnetic anomalies and details.UBAS provides a quick and efficient method for difficult exploration on the ground and small area of aeromagnetic survey.

HW exploration area is located in the south of Chaoshui basin,its topography shows piedmont alluvial tilt gobi plain and low hills,and the hard and loose sand gravels cause serious impact on the effective detection in coal seismic exploration.How to choose effective gathering parameters is the key to guaranteeing the effectiveness of seismic exploration in the area.Based on seismic exploration experience obtained in adjacent regions,theoretical analysis and experiments,the authors obtained the excitation parameters of well depth,power charge,well combination and well spacing of different areas.Combined with the geological features of the exploration area,the authors selected the combination of multiple linear detectors and built the multifold observation system.The choice of acquisition parameters was carefully constructed and good effect was achieved.The results provide valuable experience and examples for coalfield seismic exploration in similar regions in the future.

The anomalies composed of ore-forming elements may not correspond with the known deposits. Some trace elements are accumulated during the mineralization process whereas some elements are depleted. The combination of the ore-forming elements and other trace elements influenced by mineralization may enhance the effect of geochemical exploration. In this study, high-dimensional data were converted into one-dimensional data for analysis by projection pursuit model based on RAGA. The projection values and the weights of elements can be calculated by this method. Moreover, important information will not be lost and the noise data will be deleted. In addition, this method is very robust. By the case study of a Pb-Zn deposit, it is found that some deposits are not in anomaly areas or some deposits do not have corresponding anomalies. However, the ranges of anomalies obtained by this method correspond with the known deposits better. The results of PPC highlights the anomalies associated with the known deposits and, moreover, the anomaly information has not been lost. The projection pursuit model combined with RAGA by using multiple elements performs better on high dimensional data and identifies stream sediment geochemical anomalies effectively and accurately.

Base on the high density resistivity method, the network parallel electrical resistivity method develop the AM array and ABM array take the place of the normal electrical detection method, it makes the electrical resistivity method detection more efficiency. By studying the feature of the two array transform into tri-electrode arrangement and Schlumberger electrode array, the AM method data can be transform into the ABM method data, such as all kinds of electrical detection method data in study. By comparing the AM array to derive the Schlumberger electrode array with the results of the ABM array measured Schlumberger electrode array, the results shows that the two results are basically the same.The research results show that this method can be powered by a once AM array work, getting all kinds of electrical method data, this method can improve the network parallel electrical method detection, it also can get multi-angle analysis the object's electrical characteristics and differences.

In order to utilize the horizontal components' information effectively in fixed TEM data interpretation, the authors conducted some simulations of three-components under different conditions and revealed that horizontal components have the characteristics of pointing to the ground projection center and relating to the attitude of the anomalous body. On such a basis, the authors made an interpretation of field data with horizontal components' characteristics and compared the results of horizontal components' qualitative interpretation with the results of z components' quantitative interpretation. It is indicated that their interpretation results are consistent with each other, the combined interpretation of the three-component overcomes the limitation of single component, and ensures the reliability of the inversion results.

Based on a study of the change in the resistivity for voxel in homogeneous half-space, this paper describes the basic principles of the response function. Focusing on the symmetric four-pole sounding, this paper also deals with the basic idea of equivalent-depth-mode electrode sequence method. With a practical example, the advantages of this method are discussed in the aspects of optimizing the sequence of electrodes, increasing the density of target depth information, and improving the capability of depth resolution. Based on the inversion results, this paper analyzes the feasibility of the estimation of the depth of the anomalous body by using the equivalent-depth-mode electrode sequence method.

In this paper the authors proposed three methods to calculate the apparent resistivity for frequency domain controlled source electromagnetic methods. Comparison was carried out involving the analysis of their related theory, 1-D geoelectric forward modeling results and field data. The results show that the wide field apparent resistivity can better interpret the geological base resistivity and has such advantages as strong anti-interference capability but has the shortcoming of complex formula. The far field apparent resistivity with simple formula and likewise strong anti-interference capability gives less information on the base resistivity. At far field and transition zone, the result from the wide field apparent resistivity is similar to that of the apparent resistivity method. The result of the Cagniard apparent resistivity in the far-zone is similar to that of the two methods mentioned above with the simple formula, in which extra magnetic field is required which leads to relatively weak anti-interference capability and poor efficiency. However, the method can not resolve the base resistivity. The comparison of the resolutions on the base resistivity shows that the wide field apparent resistivity is the most favorable method among these methods, followed by the far-zone apparent resistivity, and the last is the Cagniard resistivity. However, the formulas of the last two methods are relatively simpler. The computation cost for the last two methods is less than that of the first one. The inconsistency of the three methods is observed at the far field, which absolutely needs further studies.

In Ledong-Lingshui slope-break belt of Qiongdongnan Basin in western South China Sea,the stratigraphic dip changes a lot,the sedimentary facies is complex and there is abnormal high pressure zone.All these factors make the velocity analysis complicated while velocity is the key to convert time to depth and to predict pressure.So it is important to ravel out the velocity change rules and influence factors in the slope-break belt.For this purpose,the authors analyzed the seismic velocity volume and well sonic data to get the velocity distribution regularity and found that it corresponds to the ordinary distribution rules except for an abnormal low velocity zone spread out from Lingshui to Huangliu formation,which fades away from shallow layer to the depth and from downslope to upslope.In combination with the geology and pressure information,it is found that the main factors influencing the velocity change rules include depth of water,formation dip,pressure,abnormal lithologic body et al.Based on above understanding,the authors applied the slope-break belt velocity volume to three sand bodies' time-depth conversion.Different calibration cases are comparatively studied with the time-depth relationship and time/velocity/depth contour map.At last the most reasonable calibration methods were chosen for different sand proposal wells.

The technology of using phase model to establish sedimentary geology model has become mature,but for volcanic gas reservoir,the single phase modeling method still has limitation.Therefore,in view of the overlying volcanic single control characteristics in Changling gas field,the authors,from the perspective of "volume control",used boundary point encryption projection correction,varied azimuth,weighted average and local grid encryption technology to establish three-dimensional geological model which could effectively solve the modeling problems such as the volcanic gas superimposed relationship,structure abnormal point,communication and resolution.This body control modeling technique was applied to horizontal well design and geo-steering,and realized the three-dimensional trajectory control,which can effectively improve the ratio of gas drilling in horizontal well.

In seismic exploration,the low frequencies have played a significant role in increasing the resolution of seismic images in recent years.In practice the geophones usually have 10 Hz natural frequency,which indicates the distortion of the seismic signals bellow 10 Hz.The broad replacement of 10 Hz geophones with the low-frequency geophones can get "real" low frequency.This replacement process however,meets with many challenges, such as difficulties in research,long period of experiments,and high cost of low-frequency geophones.To mitigate the difficulties caused by these challenges the authors propose a practical method to estimate and recover the valid low frequencies of the conventional geophone data. In order to solve the problem of low frequency distortion in conventional geophone seismic data,the author put forward a practicable conventional low-frequency detector recovery method for low frequency geophone and,on the basis of homologous concurrent data,estimated the lowest effective frequency of conventional geophone and constructed the inverse filtering operator so as to realize low frequency recovery of conventional geophone seismic data.The practical application of B3Q shows that this technique can effectively recover the low frequency information of the conventional detector,expand the effective frequency doubling of seismic data,and improve the seismic data for solving the problem of lithology,thus having a broad application prospect.

Seismic attenuation is an important factor which reduces the seismic resolution.The estimation of quality factor (Q) is the essential part of seismic attenuation research.Based on the time-frequency spectrum,the conventional Q estimation methods contain the spectrum ratio method and the centroid frequency shift (CFS) method.The estimation of Q by surface seismic data can be applied in the whole area and hence it is more feasible and economical.However,they are susceptible to compound disturbance.The separation of similar background method can be introduced to weaken the compound disturbance.The CFS method based on the frequency weighted exponential (FWE) is a stable estimation method but its theoretical accuracy is limited by the seismic wavelet spectrum principle.In this paper,the authors propose a more accurate and stable Q estimation approach by modifying the fitting method.Simulated and field data results demonstrate that the proposed method can estimate the quality factor Q more accurately and stably,which is important for improving the seismic resolution.

Electro-geochemical extraction technique, as one part of the deep-penetrating geochemistry, has been widely used in the exploration for mineral resources and proved to be very useful. During the extracting process, it is critical that provide stable and continuous electricity power to the extracting electrodes. By now, it is still some problem remain to be solved. A kind of device called HD-2014 portable and multi-function electro-extraction is developed. It is 8.8 cm×8.8 cm×2.3 cm large and with a weight of 140 g. Four types of constant voltage output including 4.5 V, 6 V, 9 V and 14 V can be achieved using this device. And also, stable output of 10mA can be achieved. The extraction time can be set from 1 to 99 hours and the status can be showed in time. Test results acquired indoor and in field demonstrated that the maximum error of voltage and current are 1.38% and 0.60% respectively, which could assure the consistence of the electric field and current intensity.

The data of airborne gravimetry measurement is easily interfered by the dynamic movement of planes,and the quality of the data of airborne gravimetry will also decline when the dynamic movement of planes is strong.Through digital filtering, most of the noises in gravity anomaly data can be removed.However,a part of noises overlapped with useful signals cannot be wiped out.Using empirical mode decomposition,we can process a group of measured data in depth which have great influence on dynamic movement of planes.The result indicates that the dynamic errors caused by the dynamic movement of planes could be eliminated without affecting the data resolution of airborne gravity anomaly,thus enhancing the internal accord accuracy from 1.43 to 1.27 mGal.

On the basis of MapGIS component technology, the Visual Basic programming multielement geochemical profile map can be drawn quickly. With this program, hundreds of multielement profile curves are drawn in a few minutes, and each profile could form a point file and a line file. Therefore, the efficiency is greatly improved.

Wavelet transform,empirical mode decomposition and singular value decomposition are effective means to highlight the deep anomaly and improve the signal-to-noise ratio of ground penetrating radar (GPR) data.This paper proposes a fast short-time Fourier transform technique for interpreting ground penetrating radar (GPR) noise signal.The frequency spectrum differences between transmit signal and noise signal are used to improve signal-to-noise ratio of radar data.It is verified by using a numerical example.The method and the wavelet transform as well as the advantage of empirical mode decomposition method are analyzed in detail respectively from single signal frequency energy difference,frequency equivalent distribution difference,and other aspects.The results show that the short time Fourier analysis technology can achieve rapid interpretation of GPR data and,for the ground penetrating radar data inversion imaging,it can provide more precise constraints.

2.5D joint inversion of gravity and magnetic module in RGIS data processing software uses 2.5D human-computer interaction inversion method of gravity and magnetic anomalies,which has advantages of simple interface,convenient operation,and real-time display of inversional curve. Taking inversion of GanC-2011-0011 aeromagnetic anomaly in the Dunhuang area of Gansu Province as an example,this paper describes concrete methods of data import,parameter setting and modeling. The inversion result is basically in accord with verification result with drilling. It is shown that the inversion result is reliable.

Anisotropy is widespread in subsurface.The rapid development of PC-Cluster and field seismic acquisition makes it possible to take anisotropic medium into accounted.Scalar wave equation and its RTM,based on acoustic approximation,has becoame a hot issue of the industry.It can overcome the complexity of elastic modeling and computational limitations.In this paper,the authors derived the scalar acoustic equation on the basis of elastic wave theory in anisotropic medium.According to this equation,the authors put forward a reverse time migration strategy.The numerical simulation shows that the scalar wave equations in this paper can better suppress shear wave interference.RTM result of Hess model demonstrates the feasibility when it is used to RTM.

The deep water zone has great oil and gas potential,and hence it is treated as key field of exploration.The great variation of water depth, the roughness of seafloor and the complex geological setting make it difficult to conduct seismic imaging of the target object.Velocity building is one of the greatest difficulties.The rich refraction wave in the OBS (ocean bottom seismometer) data was used to invert the velocity model with the method of travel time inversion.The OBS was acquired by Guangzhou Marine Geological Survey in the east part of Pearl River basin on the north slope of South China Sea.The OBS data have good quality with refraction wave clearly observable.The imaging result shows that in the region of rugged seafloor, first arrival travel time inversion can provide the background velocity model needed by seismic imaging.Limited by the high frequency approximation,the velocity model has low resolution.More advanced full waveform inversion can provide high resolution model,with first arrival travel time inversion result as the initial model.