With the help of regional geochemical exploration results, especially the geochemical maps of different elements, geological interpretation can serve as an important auxiliary means of geological mapping in the North Bayan Mountains, Qinghai Provence, thus significantly improving the mapping efficiency and accuracy. The results show that regular content changes of elements such as some rare elements and rare earth elements like Y, Nb and sulfur group elements as well as iron group elements like Cu, Zn, Cr, Co, and Ni in different units of the Bayan Har Mountain Group can be used as important means in internal stratigraphic division and regional stratigraphic correlation of the Bayan Har Mountain Group. Furthermore, faults can be inferred and mapped; especially hidden faults and regional faults in shallowly-covered areas can be recognized and mapped remarkably effectively by using certain element anomalies with spotted and beaded characteristics along the faults (such as Sb, Hg, Bi and Pb) as well as along the straight boundaries of geochemical divisions (such as Sb, Bi, As and Pb).

Taiwan Strait basin is commonly regarded as a good petroleum-bearing area. However, the previous studies were all focused on the data from geophysics, with no direct evidence from petroleum geochemistry to prove the existence of economic oil or gas reservoirs in these areas with good petroleum prospects. In this study, the concentrations and carbon isotope ratios of the soil acid-extraction hydrocarbon from the sea surface sediments in Jinjiang depression and Jiulongjiang depression of west Taiwan Strait basin were analyzed to study the microseepage and origins of the petroleum-baring system, with the purpose of providing the proven geochemical information for petroleum exploration. The result of surface geochemical exploration for oil and gas in the west Taiwan Strait basin indicates that there exist two kinds of hydrocarbon resources: one is oil-gas and the other is single dry gas, probably related to two suites of source rocks in this area. These two kinds of resources make different contributions to the two depressions in the study area, where hydrocarbon of the Jiulongjiang depression is mainly from source 1, and source 2 mainly contributes to the hydrocarbon reservoir of Jinjiang depression.

Uranium extraction methods could be divided into conventional uranium mining and in-situ leaching. Conventional mining is suitable for hard rock uranium resources, whereas ISL is usually adopted for sandstone uranium deposits. ISL is a new mining method by injecting specially formulated leaching solution to recover uranium. Concentration gradient distribution range is surely to be formed accompanied by a series of solute transport process during the leaching course. For the range and process above are closely related to coverage area (rate) of orebody, recovery rate of resources and pollution range, control of underground water and some other important problems, a monitoring job for the range and process is essential. Until now, there are no mature methods both in China and abroad and relevant researches are inadequate. A research on leaching solution range and solute transport process was taken by performing a group of tests of CSAMT and TDIP survey in Erlian Basin in the paper. Combined with the data from regional geology, hydrology, formation resistivity, logging, rock polarizability and characteristics of formation resistivity, the authors gave an interpretation and obtained a 2-D resistivity model and a polarization anomaly distribution model of the structure below the wellfield studied. A suite of geophysical monitoring methods for solute transport process of in-situ leaching uranium were made.

The black rock series of the lower Cambrian Shuigoukou Formation exposed in Zhongcun-Xianghe area lies in the middle belt of Qinling area, and constitutes the typical strata of the black rock series and the main ore-bearing layer for gold and vanadium ore deposits in this area. The strata consist of a set of carbon, silica, argillite and carbonite formations, and the rocks include silicalite, carbonaceous silicalite, claystone, carbonaceous limestone, and carbonaceous-siliceous slate, which contain P-Mn nodules locally. Geochemical research on the strata reveals the following phenomena: Firstly, rocks are obviously rich in V, Au, Ag, Cu, Zn, Mo, Ni, Pt and Pd, and experienced intense differentiation and obvious superimposition-reformation, which was geochemically favorable for mineralization. Secondly, P-Mn nodules, claystones and silicalites are the most advantageous types of ore-bearing rocks. Thirdly, the values of ore-forming elements, especially V, Ni, Zn, Cu, Ag, U, PGE and the grade of ores are closely related to the content of carbon (TOC%) in the rocks. What's more, the distribution of deposits related to the black rock series of the Shuigoukou Formation is characterized by Au (Ag) in the western part and V in the eastern part, Au-V in the northern part and and Ag-V in the southern part. Grade of ores and content of carbon in rocks are featured by higher in the west and lower in the east, higher in the north and lower in the south, which indicates that the northern belt is much more favorable than the southern belt in prospecting, and that the western belt is more favorable than the eastern belt. These opinions are much significant for choosing the main and associated mineral types, indicators and ore-prospecting directions in further prospecting work in this area.

The granites in Xinchenggou area of Dongning County are located on the active continental margin of eastern part of Xing'anling-Mongolian orogenic belt. In this paper, petrologic and element geochemical studies were carried out for granites in Xinchenggou area, Dongning County. Major element geochemistry shows that the rocks are calc-alkaline and I-type granites, and are also characterized by enrichment of alkali, relative enrichment of potassium and S-type syn-collisional granites. The Rittman index δ is from 1.41 to 2.11. The alumina saturation index ACNK is from 1.02 to 1.20. REE concentrations are low ( ΣREE=72.35×10 ^-6~217.64×10 ^-6 ) and show obvious differentiation between LREE and HREE ( La_N/Yb_N=2.74~11.37 ), with apparent Eu negative anomalies ( δEu=0.14~0.83 ), and the abnormality of δCe (δCe =0.96~1.11) is not apparent. In addition, the rock mass is relatively poor in such elements as Nb, Ta, P and Ti, and rich in Rb, Ba and K . w(Nb)/w(Ta) ratios of trace elements are less than 16.2, suggesting that the magmas were formed by partial melting of the crust. The magmas were formed by collision between the North China plate and Siberia plate in Late Paleozoic-Early Mesozoic period and subduction of the paleo-Pacific plate towards the east edge of Eurasia in Late Triassic. The magmas also had the characteristics of multi-stages and complex genesis. Geophysical and geochemical anomaly, geochemical characteristics, and geochemical ore parameters indicate that this area has prospecting potential for epithermal-type Au-Ag-Cu deposits.

Wudalianchi consists of volcanoes formed in late Quaternary multiple eruption. For the purpose of selecting site for hot dry rock exploration and development, a new round of geophysical exploration was launched. Based on complete magnetic survey data obtained in Wudalianchi in recent years, in combination of magnetotelluric surveying and seismic tomography results, the authors re-understood and explained the existing magnetic exploration data. By a comparison with gravity and magnetic field, the authors emphatically investigated Weishan central type eruption formation volcanic dome structure, magmatic sac dynamic mechanism and geological background reflected by gravity and magnetic field, whose characteristics are different from features of Bijiashan-Laoheishan fissure eruptions. Therefore, the results obtained by the authors can provide geophysical information and evidence for studying and discussing the existence of hot dry rock in the deep part of Wudalianchi volcanic edifice.

Structural plane is an important influencing factor for the rock mass quality, 3D modeling, borehole hydraulic test and engineering design of underground research laboratory. Xinchang rock mass in Beishan area has been chosen as the preferred site for URL on geological disposal of high-level radioactive waste in China. The characteristics of structural plane in Xinchang rock mass were obtained based on acoustic borehole televiewer and other geological information. The results indicate that the granite rock mass with a high massiveness is beneficial for construction of URL. The width of faults around the preferred site and incidence in horizontal and vertical directions decrease with the depth. Characteristics of dip and strike of structural plane are the same as features of other structures in this area. The research results provide meaningful information for design of URL and further geological research.

Xunhua region of Qinghai is located in the joints of the Qilian orogenic belt and the west Qinling orogenic belt. In order to reveal the structural feature, and determine the key metallogenic prospect areas, the 150 000 high precision magnetic survey was carried out in the selected area. The azimuth of survey lines is north east to 30°, 391 pieces rock (mineral) magnetic specimens were cellected. through the analysis of the magnetic parameters, characteristics analysis and interpretation of magnetic anomaly, the ZongWuLong-tianshui thrust fault F1 towards NW50°. The key metallogenic prospect areas are mainly distributed in the northeast of the surveyed area, by caledonian period intrusive mass of JiShiShan ultrabasic diorite and LeiJiShan basite granite, and have high mineral content. This work shows that the high-precision magnetic survey is one of the important basic methods in regional geological survey and mineral survey, provides geophysical basis for the next step of mineral survey in the investigated area.

Due to the common coverage of aeolian sand, the effect of conventional geochemical exploration methods is limited in eastern Inner Mongolia, which leads to the inefficiency of concealed ore exploration in spite of superior metallogenic geological condition there. In order to select most effective geochemical exploration methods suitable for eastern Inner Mongolia, the authors studied the effectiveness and practicability of thermal magnetic components and fine-grain survey in the Luokedun lead-zinc deposit. The results are as follows: At orebody location covered by the depth of 90m, two methods all can delineate the anomalies clearly. Thermal magnetic component survey has the advantages of stronger intensity and better continuity, whereas fine-grained soil survey has the convenient and relatively economical advantages. For the overlying thickness of over 200 m, the anomaly of thermal magnetic component survey is more obvious relative to the anomaly detected by fine-grained soil survey, and the anomaly is fairly consistent with the known orebody. Therefore, it is better to choose the method of thermal magnetic component survey to explore concealed ore deposits whose buried depth is over 90m in eastern Inner Mongolia.

The problem as to whether a stable and traceable geochemical model can be obtained by different sampling densities and different sampling time spans constitutes an important basis for testing the reliability of geochemical methods. In this paper, the authors conducted fine sampling densities and sampling time spans over the Huaniushan Pb-Zn deposit of Gansu Province. The conclusions are as follows: the media values and background values of elements obtained by different sampling densities and different sampling time spans are consistent, the geochemical patterns are very similar and reproducible, and so the stable and traceable geochemical patterns can be achieved. The larger the sampling spacing, the more scattered the values, suggesting that the distribution of elements is characterized by local heterogeneity. It is thus held that researchers can portray the details of changes of geochemical patterns and further track the mineralization bodies by increasing the sampling density.

the routine time domain induced polarization can only obtain two parameters, i.e., resistivity and polarizability, which often makes it difficult to accurately interpret induced polarization anomaly and thus causes less information for orebody interpretation and poor detection resolution. Such a phenomenon is especially prominent in the exploration of some ore resources characterized by associated or accompanying minerals like carbonaceous limestone, pyrite and limonite whose resistivities or polarizabilities are close to each other. In order to enrich orebody geological information, improve the understanding of orebody and reduce mistaken or incomplete judgement, the authors utilized the feature that Cole-Cole model could describe time response of induced polarization effect and employed damping least squares method to realize the best fitting of the time response with time domain Cole-Cole model so as to obtain varied kinds of Cole-Cole model parameters. Practice shows that this method is economical and effective and, through integrated interpretation of varied kinds of physical parameters, it can realize more overall understanding and correct induction and interpretation of induced polarization and also improve the resolution of the time domain induced polarization in deep prospecting.

In this study, soil samples before and after geo-electrochemical extraction were collected along the fifth exploration line of the Luokedun lead-zinc polymetallic mining area. Total content and chemical speciation of 'seven steps method' were analyzed for 20 elements. Some conclusions have been reached: Elements extracted by geo-electrochemical process exist in a variety of phases in soil. The active phases including water soluble, exchangeable and carbonate bound phases are the mainly components, while micro-particles that exist in low active phases including residues can also be migrated and adsorbed by this process. Spatial distribution of element values of some active phases in soil appear to be highly consistent with spatial position of the orebody after geo-electrochemical extraction. Factors such as low depth transported overburden and orebody or mineralized body beneath the cover can lead to a significant increase of total content in soil for the majority of metal elements after the extraction process. Such phenomena indicate that the method of geo-electrochemistry has great applicability in the transported overburden area.

The quality of seismic data has been improved with the application of variable-depth streamers (VDS) acquisition,which leads to diversity of receiver ghost notch,and the key advantage is the utilization of notch diversity to combine different depth receivers,thus achieving the final better result which has no notches.This paper focuses on the effects of VDS acquisition on frequencies especially on low frequencies that benefit the images of deep geological structure.The slope function provided by this paper can effectively gauge the extent of low frequencies,and it is easy to find the frequency difference between shots modeled by conventional constant depth streamer (CDS) and ones modeled by VDS;In addition,considering the ghosts caused by the marine free surface,the method outlined in this paper derives a surface datum ghost free result of input shot gather data by using the modified least squares linear Radon equations.Its application to model data and real VDS seismic data shows that this deghost algorithm can effectively suppress the ghosts.

The Qiongdongnan basin LING A in the South China Sea is a complex fault block oil and gas field,which is characterized by complicated fault block in deep strata and great changes in vertical and horizontal velocity as well as low S/R.All of these factors lead to an unreliable imaging results.This situation seriously restrict the residual oil exploration.The key to solve this problem is to improve the accuracy of PSDM imaging with high precision velocity modeling.This paper presents a high precision 3D velocity modeling method based on geological constraint.On the basis of tomographic velocity modeling,the horizon and fault interpretation are used to constrain tomography inversion.This method designs a new strategy to update the velocity model,and improves the construction of initial model.The 3D velocity field is improved by new workflow,and the quality of profile of PSDM imaging is also enhanced.The results obtained by the authors confirm that the new velocity modeling method can provide the basic data for the interpretation of fine horizon and implementation of fault block.

The results of petro-physical research show that pre-stack elastic parameters and multi-parameter intersection are more sensitive to reservoir and hydrocarbon,and the pre-stack inversion based on this conclusion is an effective method for quantitative prediction of the oil-bearing reservoir.As for compact and thin sand reservoir and its oil-bearing property,because their seismic response are extremely concealed and the seismic resolution is deficient,the high-resolution pre-stack stochastic inversion based on variogram is widely applied.However,the high frequency contents of pre-stack stochastic inversion have strong randomness and low reliability,which exerts a great impact on the accuracy and reliability of the prediction results.In order to solve these problems,the authors took the prediction for compact and oil-bearing thin sand of Jurassic Shaximiao Formation in north-central Sichuan Basin as a study case and,after analyzing the sensitive elastic parameters of reservoir and its oil-bearing property,carried out the application research on the high-resolution pre-stack inversion method based on seismic waveform indicator.The method uses the similarity of pre-stack seismic waveform instead of variogram to optimize well samples,and builds the initial model of each elastic parameter by stochastic simulating based on the optimization samples.Under a Bayesian framework,the method combines the initial model,the prior probability distribution of well elastic parameters and the inversion elastic parameters of pre-stack simultaneous inversion to build the posterior probability distribution of each elastic parameter,then resamples the posterior probability distribution function using Metropolis-Hastings method to get a convergent and stationary distribution which is also an inversion result.The practical application shows that it can get a high-resolution and broadband result of each elastic parameter in the formation from the pre-stack seismic data by using the pre-stack inversion based on seismic waveform indicator,and the high frequency contents of the result are more certain to raise the prediction accuracy and reliability of compact and thin sand reservoir and its oil-bearing property.It has extensive application prospect as an effective method for high-precision prediction of the reservoir and the oil-bearing property of compact clastic rocks in terrestrial facies.

The transformation of zero phase into small phase in vibroseis seismic data processing is a problem of controversy: Is it a necessary process? when will is be conducted ? What is its influence on seismic wavelet? The authors analyzed small phase transformations of the autocorrelation wavelet sweep signal of vibroseis, the simulated earth absorbed wavelet and the practical vibroseis data wavelet. The authors have found that phase drift phenomenon is inevitable in the phase transformation process,and propose the modification method,which can to some extent solve the problem of the phase-shift. The authors affirmed the necessity of phase transformation,and put forward the optimal order to conduct the processing.

The industrial interference in Tongchuan City survey area is strong, where stratigraphic sedimentary types are complex, the lithology varies remarkably, the terrain is fluctuating, and the gully and the ridge are crisscross. The audiomagnetotelluric method (AMT) is characterized by a single point of measurement, great detection depth, high horizontal resolution and other technical advantages. At the same time, the magnetotelluric remote reference technology can suppress random noise, restore the "dead band" data, and improve the magnetotelluric data quality. In order to study the application effect of magnetotelluric remote reference technology in the urban strong electromagnetic interference environment, the authors constructed an audio magnetotelluric profile in Tongchuan investigation area. The nonlinear conjugate gradient (NLCG) method was used to carry out the data inversion and data analysis. The results show that the application of remote reference technology to the processing of magnetotelluric data can effectively improve the quality of noise data, and the inversion results are more consistent with the geological data.

Akekule Formation of Triassic developed delta front subaqueous distributary channels in Tahe area.The channel sand matched with the low amplitude structure and formed low amplitude structural lithologic complex traps.However,due to the rapid change of the lateral migration of the channel,thin sand,strong heterogeneity,and other factors,the reservoir prediction accuracy needs higher requirements,which restricts the development effectiveness.In view of such a situation,the authors used the high precision 3D data and,on the basis of forward modeling and reflection analysis,extracted multiple attributes under the constraint of sequence frame. In combination with stratigraphic slice method,the authors clearly determined seismic reflection characteristics in this area,described the river boundary form,divided the river stage and predicted the thickness of river channel.The results show that the application of multiple attributes analysis and stratigraphic slice can accurately identify the boundary of river channel,and divide the period of river channel to improve the accuracy of reservoir prediction.

This paper points out that the previous calculation formula of the accuracy of the airborne gravity and magnetic survey does not conform to the statistical principle. The authors present a new calculating formula, which unifies not only the consistency of multi-instrument precision calculation for gravity and magnetic measurement on ground but also total precision calculation formula for airborne gravity and magnetic measurement using the intersection of survey line and tie line, and can be applied to aeromagnetic gradient measurement to eliminate gradient steering difference and to evaluate the accuracy of the gradient measurement system.

Because of the advantages of multi-parameter and the suppression of the shallow anomaly, the measurement of airborne magnetic gradient has become a new research hotspot in the field of airborne geophysical exploration in recent years. Based on AGS-863 three axis airborne magnetic gradiometer, it described the aeromagnetic gradient theory and the application research status. In order to summarize the relationship between aeromagnetic anomaly and the underground geological bodies, it designed some typical geomagnetic models, took a large number of forward simulation work, and drew the following conclusions: compared with the total field anomaly, gradient anomaly had more advantageous in the delineation of the magnetic bodies; for single magnetic body, the vertical gradient peak corresponded precisely to the center position of the magnetic body, and the longer of strike length of the magnetic body, the closer of the zero point of the main section to the abnormal body boundary, and the main section longitudinal gradient's maximum and minimum values exactly corresponded to abnormal body's left and right boundary and the main section's perpendicular section transverse gradient's minimum and maximum values exactly corresponded to abnormal body's up and down boundary; for the combined magnetic bodies, the range of the magnetic body which was locked with the main section longitudinal gradient peak and the main section's perpendicular section transverse gradient was enlarged, and the vertical gradient peak was shifted to the direction of the nearby magnetic body. By comparing the measured gradient data with the theoretical gradient data, it found that the measured gradient data has obvious advantages, and it can play a prominent role in the identification of human interference and high frequency geological information. These work could provide reference for the field data acquisition workers to understand and identify anomaly and distinguish between true and false anomaly, and provide some help for the anomaly interpretation workers.

Time-depth conversion is an important link in the use of seismic data for structural and reservoir interpretation.Previous researchers carried out a lot of fruitful work by using different methods in different geological conditions.However,the high-velocity anomaly caused by the near-source fan on the steep slope of the uplift has the characteristics of limited distribution,significant anomaly and acute change.There are some problems in the applicability of the conventional time-depth conversion method.According to the specific geological conditions of the study area,this paper proposes the technical countermeasures of time-depth conversion of the high-velocity anomaly area in Dongying Formation strata of the steep slope zone of Shijiutuo uplift.Based on an analysis of the genesis,the seismic phase technology is used to describe the high-velocity anomaly zone boundary;the seismic velocity anomaly identification technique describes the high-velocity anomaly amplitude;combined with the seismic phase,the seismic velocity and the well depth error,this method achieves the time-depth conversion,and finally obtains a more geologically meaningful time-depth conversion result.The practical application shows that the method is consistent with the conventional one in the constant velocity region,and is more consistent with the geological regularity in the anomaly area.Therefore,this methods has achieved good effect in the time-depth conversion which can strongly support the reserve evaluation of the oil and gas structure.

The distribution of sand bodies detected by the well pattern can not meet the needs of the remaining oil tapping potential in the middle and late stages of the old oilfields,because the fluvial reservoirs frequently cause the thinning of the thickness of the single sand bodies and the quick lateral change.According to the characteristics of fluvial fancies reservoir in the Gangdong oilfield,Dagang,a three-dimensional model was established for the reservoir prediction method experiment,and the method of spatial distribution of single-stage channel sand body was explored.The results show that the contribution of seismic reflection to the seismic record energy of each set of sand bodies is analyzed by means of discrete synthetic seismic records.It is found that the amplitude slices extracted from the zero reflection energy of one set of seismic reflection energies of sand bodies can reflect the other set of single sand bodies' spatial distribution,and the single sand body can be predicted by this method.The zero-value method can effectively depict the lateral variation characteristics of the cross-well sand body and provide a strong basis for determining the oil-water relationship and adjusting the well pattern deployment in the Gangdong oilfield.

In the process of measuring electric field and magnetic field components,due to interference from geological factors,power frequency,human activities,and other external factors as well as the observation system,there often exist many kinds of noises in actual data,which affect the computing of apparent resistivity and phase and the subsequent forward and inversion work.In order to improve the processing effect,the authors applied the TI wavelet denoising method based on improved threshold to the denoising of magnetotelluric signals on the basis of the existing fast algorithm.By using the denoising method,not only the noise can be removed effectively,but also the original shape of signal can be preserved at a large extent.After dealing with the measured magnetotelluric signal data by this method,the authors detected that the denoising method can make the mutation phenomenon under effective control and decrease,and furthermore it improves significantly the quality of time series,apparent resistivity curve and phase curve,thus it has a good denoising effect for magnetotelluric signal.

The double sparse dictionary is adopted for the seismic random noise attenuation.The seismic data are not represented well by the fixed dictionaries,which do not contain the effective information about the seismic data;the learning dictionaries are fully adaptable but are costly to deploy in the big data processing.The double sparse dictionary reduces the number of training sample and is more suitable for the construction of high-dimension dictionary and the analysis of the high-dimension signal. With the over completed discrete cosine transform as the base dictionary,the sparse dictionary is trained by the sparse K-SVD driven by the noisy seismic data samples.Thus the seismic random noise attenuation model based on the double sparse dictionary is established.A comparison of the results of the synthesized and real data in high dimensional case shows that the seismic random noise can be suppressed effectively by the method based on double sparse dictionary and the fault structure can be preserved in 3D case.

A kind of quality evaluation method in airborne gravity survey is proposed in this paper.The accuracy of the flight and survey line is quantified by calculating the root mean square of discrepancies between measurements at intersection points of survey line and all tie lines.Using this method,data of three survey areas measured by GT-1/2A gravimeter were analyzed,and the statistical distribution of the accuracy of flight and survey lines were obtained.This paper tries to provide a new method and evaluation indexes for quality control procedures in airborne gravity acquisition projects.

In this paper, based on the measurement result of water electrical parameters in Shanglinhulake, the authors conducted a Ground Penetrating Radar (GPR) experiment of underwater archaeological investigation with all instruments and workers on a wooden boat powered by a diesel engine. The contrast test shows reflection characteristics of different depths of water and the bottom layers in radar profiles obtained by 100 MHz, 200 MHz and 400 MHz frequency antennas respectively. On such a basis, the authors processed and analyzed GPR data and drew the conclusion as follows: the GPR can not only clearly observe various underwater archaeological targets such as an ancient dam, Yue kiln remains, ruins of ceramic, an ancient river and convex quays for cargo ship but also form images for several local anomalous bodies buried in the lakebed strata with high-resolution. Finally, all of these survey results were confirmed by diver inspection.

In the process of geological disaster investigation in the Xiangtan manganese ore district and its surrounding areas, the geological achievements were studied, the present situation of collapse in the area was analyzed, and the geophysical detection technology was used to make evaluation quickly and effectively. Firstly, the characteristics of geological, strata and structure in the area were described. Secondly, the existing subsidence area was studied and the geophysical methods were designed according to different typical areas. Finally, according to the drilling results, the evaluation of the collapse in the area was realized. The research results show that the detection effect is obvious, the regional collapse can be divided into four categories, and the geological disasters caused by it have unique characteristics. The results obtained by the authors provide the basic data for later treatment.

In limestone area, groundwater runoff, soil cave, loose body and well-developed karst caves often result in ground collapse so as to influence the safety of ground building. Cement slurry grouting in limestone foundation is an economical, reasonable and effective method to prevent ground collapse. In order to get various kinds of information, such as the distance of cement slurry grouting, and the conditions as to whether soil cave, loose body and karst cave are filled with cement slurry and whether grouting is dense and uniform, researchers can use borehole electromagnetic wave to carry out cross-hole inspection for grouting quality of cement slurry.