There exists close relationship between intermediate-acid intrusive rock and regional mineralization in the southeast of Hubei Province. According to the features of rock bodies and geophysical properties of the ores and the model put forward by geologists, the authors set up a geological-geophysical model which is characterized by multi-identifying information and identifying mark. And then, the authors used actual data to prove it. The authors extracted weak local gravity and magnetic anomalies to compare theoretical model's combination with local gravity and magnetic anomalies on different scales with the effect of the theoretical model through wavelet multi-scale decomposition, from which the authors have drawn the conclusion that low gravity-high magnetic local anomalies are caused by rocks, whereas high gravity-high magnetic local anomalies are caused by large scale mineralized body on large scale details; high gravity-high magnetic local anomalies are caused by mineralized body on small scale details. On such a basis, the authors delineated 13 low gravity-high magnetic local anomalies and high gravity-high magnetic local anomalies areas which may have concealed rock bodies or mineralized bodies (orebodies). The authors infer that the northeast high gravity-high magnetic local anomaly stripe of Luosishan-ZKI01-Chenjiashantou, the ringlike high gravity-high magnetic local anomaly of Shizishan-Yupingshan and the high local gravity anomaly are further ore-prospecting targets, as shown by the features of known drill holes' relation to high gravity-high magnetic local anomalies.

In order to cooperate with deep prospecting in the Jiulongnao orefield, the authors carried out combined profile and area measurement of geophysical-geochemical integrated exploration technique and delineated "one belt (east-west contact zone of Guting limestone and Jiulongnao complex massif) and three areas (Ⅰ, Ⅱ, Ⅲ anomaly)" as the most favorable metallogenic zone. Drilling verification disclosed multi-layered stratiform and granite contact zone skarn type tungsten polymetallic orebodies 1.62~19.37 m in thickness. Consequently, a geophysical-geochemical comprehensive prospecting model for this area was built up, characterized by "two-lows and three-highs". The two-lows are low gravity and low apparent resistivity, whereas the three-highs refer to high ΔT, high apparent polarization and high amounts of chemical substances (W, Sn, Bi, As, Sb, Hg etc.) in the earth. The tungsten polymetallic mineralization in the area was closely related to magmatic activities in Yanshanian period, and mineralization was controlled jointly by strata, magmatic activity and structure. Therefore, the selection of survey areas must be chosen around granite boby or hidden granite with strong responses to low gravity and fault structure with strong Hg anomaly in soil. Based on the above understanding, it is pointed out that the depth of the southern part of the area has metallogenic potential in that it is equipped with optimum coupling of formation (Guting limestone)-structure (F₁, F₂ fault)-magmatic rock (deep concealed granite) , thus having favorable metallogenetic conditions.

In order to solve the difficult problem of reservoir spatial form and favorable prediction of subtle marine reef reservoir in the Changxing Formation of the Xinglong gas field in Sichuan basin,the authors first built the reef seismic forward modeling to reveal the unique seismic response pattern as "up-convex shape,internal event messiness,reflective events increase and frequency decrease". On the basis of the reservoir seismic characteristics,optimization analysis is processed for the multiple seismic attributes, including geometric shape class,wave group statistics class and frequency class.The boundary shape characterization of reef reservoir is studied by multiple attribute clustering.Secondly,neutron pseudo-acoustic curve is selected to constrain model-based iteration inversion method to predict reservoir thickness.The nonlinear equation method is adopted to convert velocity inverse result to porosity of the reservoir.Finally,the storage factor is obtained to explore the optimal matching of reservoir thickness and porosity characteristics.And the reef reservoir spatial distribution features are quantitatively predicted.This prediction method reveals spatial distribution characteristics of reef reservoir,improves prediction accuracy, and provides certain references for reef reservoir prediction research.

The Early Cretaceous basin of the Liupan Mountain in Ningxia has abundant mineral resources of ointment and salt. Ningxia Geology Bureau has found rock salt layer whose thickness is between 42.38 and 256.11 m in ZK101 and ZK201 in Zhongkangxiang and Guodianzi villages of Yuanzhou District, Guyuan. The area has prospecting potential in finding rock salt minerals. Strata and structures (including fracture), rock salt and other physical parameters or abnormal characteristics were extracted by utilizing existing seismic section, gravity and electrical profile data, combined geological profiles, drilling and logging data. The characteristics of the geophysical prospecting methods were summarized, and the most effective combinations of exploration techniques and methods were proposed. There are nine prospecting targets in the area, and the current survey area is III target area, with the discovery of a rock salt mine of 2.6 billion tons; further work is carried out in II target area, with the discovery of a total amount of 4.9 billion tons of resources in II and III target area. The research results provide important geophysical foundations for regional economic development and prospecting.

Located in the Pu'er longitudinal axial fracture belt of Lanping-Simao Mesozoic rift basin, the Paduanshan mining area possesses extremely favorable mineralization environment. Based on 1∶25 000 geochemical soil survey and an analysis of the geochemical characteristics of the elements and geological background of the area, the authors delineated 12 comprehensive anomaly areas and divided them into six integrated anomaly zones. At the AP6 comprehensive anomaly area which belongs to No.Ⅰintegrated anomaly zone, four copper orebodies and one low-grade gold orebody were discovered, and the prospecting program obtained promising result and good effect. In combination with an analysis of metallogenic geological conditions, it is reasonably believed that the Paduanshan mining area has excellent prospecting potential and is extremely favorable in search for epithermal filling metasomatic gold and copper deposits. If prospecting work is continued in this area, it is expected to get breakthrough soon.

Northern Hebei Province is a prospective area of volcanic rock-hosted uranium deposits. Based on the 1∶200 000 stream sediment and regional rock data, this paper discusses the spatial and temporal distribution of U in northern Hebei Province in order to provide geochemical information for uranium exploration. In spatial distribution, the high background values of uranium are distributed in the late Variscan folded zone in Inner Mongolia and Inner Mongolia axis, and are focused on the zone of Shiyaozi in Chongli County-Senjitu in Fengning County-north Guyuan County-north Weichang County. Uranium geochemical abnormal belt corresponds with the south of the Hongshanzi metallogenic belt. The formation of U geochemical anomaly is controlled by geological bodies which are intermediate-acid rock mass of Yanshanian epoch and acid volcanic rock of Zhangjiakou strata and Dabeigou strata, NE-trending faults and volcanic basins. Uranium geochemical anomalies are closely related to uranium deposits. Uranium deposits are located along the uranium anomaly belt, and hence uranium anomalies can be used as uranium ore prospecting indicators. In temporal distribution, U values have a tendency to increase and are enriched in late Jurassic and early Cretaceous strata, but are low in Archean and Proterozoic strata.

The Wunuer lead zinc silver deposit is located in Wunuer-Wuerqihan area of Xingan geosynclines, Inner Mongolia. The surface of the whole mining area is of vegetation, and the geological prospecting indicator is not obvious. In the process of ore prospecting, the integrated geophysical and geochemical methods played an important role in the delineation of orebodies. Geochemical survey shows that the ore-forming elements include Pb, Zn and Ag, the area is large, the components are complex, and the concentration zone is obvious. With high precision magnetic method, the authors detected that the mining area is distributed in a buried rock contact zone, and mineralized rocks have high polarization rate (η_s = 3%) and high resistivity (ρ_s= 600-1 000 Ω·m). All of the above data are important indicators for ore-prospecting. This paper summarizes the geological, geophysical and geochemical characteristics of the deposit, and puts forward the prospecting method in the Da Hinggan Mountains, which provides reference for further prospecting in this region.

Based on 1∶10 000 soil geochemical survey on the Woergei gold deposit in Gansu Province, the authors used the R-model factor analysis method to evaluate geochemical anomalies. Cluster analysis of the soil geochemical data obtained from the Woergei gold deposit shows that eight kinds of elements can be grouped into three categories, i. e.,(1) Sb,As,Au,Pb,Ag;(2) Cu,Zn;(3) Hg. Combined with favorable ore-controlling factors such as lithology and structure,the authors applied the system core theory to synthetic evaluation of main ore-forming elements and the abnormal element combination,and then selected three prospecting target areas. In No.Ⅰ,Ⅱ and Ⅲ anomaly target zones,the systems of nuclear are respectively {Au,Pb},{Au} and {Cu},the system stability is strong,and the abnormal Ⅰ and Ⅱ areas were verified by drilling and pit engineering. The mineralization location,size and element anomaly concentrated heart position are in good agreement in the two abnormal zones,suggesting that soil geochemical survey is effective in the study area. However,No. Ⅲ anomaly target zone has the system of nuclear of {Cu},with the anomaly in the area displaying the main ore-forming elements Cu Au anomalies,the malachite and covellite were found in field investigation, which are relatively consistent with the anomaly target area,and hence drilling and pit engineering in the abnormal area should be conducted.

This paper gives a brief review of the seismic technology development level in uranium exploration,and decribes the application status of seismic exploration technology for sandstone type uranium deposits in China from the aspects of collection,processing and interpretation based on the results of seismic exploration work in nuclear geological system in recent years.Through the comparative analysis of the development level of similar technologies in China and abroad,the authors have found out the gaps between China and countries abroad in this field.Here are some examples of China's shortcomings in this field:lack of studying seismic acquisition methods for sandstone type uranium deposits,relatively low precision of shallow seismic data processing and interpretation accuracy,backwardness in such aspects as the work of seismic attribute analysis of sandstone type uranium ore body,prestack inversion technology research,and target sand body modeling.Aiming at tackling these problems and considering characteristics of uranium mineralization,the authors put forward some countermeasures and suggestions for speeding up the development of seismic exploration technology of sandstone type uranium deposits in China,such as optimizing the acquisition surface,detailed demonstration and testing of the coverage,developing the seismic processing technology for ultra shallow (less than 100 m) sandstone type uranium deposits and weak information extraction technology of interlayer sand,research on the technology of shallow noise removal and high precision imaging,study of the physical modeling of uranium and non-uranium bearing sandstone and analysis of the seismic attributes of the target sand body.

The authors discovered an outcrop with malachite mineralization in Ghanzi area of Botswana, with the grade of Cu up to 20%. No mineral anomalies were found here with IP sounding method and no obvious copper mineral was found in the drilling core. The authors analyzed such phenomena from the geochemical characteristics of Cu in the dry climate and reached the conclusion that the richness of surface copper in this area results from the dry climate and alkaline environment. Several problems which deserve due attention in looking for copper deposits in dry areas of Africa were also put forward.

Based on physical property parameter measurements of main rock and ore specimens from 161 surface samples and 1 134 drilling core samples in the Heishan copper-nickel ore district, the authors found that the mineralized rock body, rock body and wall rock strata all exhibit obvious differences in density, magnetic susceptibility, residual magnetization and polarizability, thus possessing favorable prerequisite for geophysical exploration. The study based on physical property difference degrees of mineralized rock body, rock body and wall rock strata and capability for forming anomalies has the following meaning: Massive high magnetic anomaly and high gravity anomaly delineated by large-scale high-precision gravity-magnetic regional sweeping survey might indicate the existence of mafic-ultramafic rock body; If large-scale IP, resistivity and magnetic survey is carried out in such a massive gravity and magnetic area and massive or pipe-like anomaly whose polarizability is higher than 10%, low resistivity anomaly in the high resistivity anomaly, relatively high or higher magnetic anomaly and gravity anomaly, the rock body in this area might have been mineralized.

There exists intimate relationship between the ground radon concentration and the terrain, and the transformation effect of the terrain can destroy the objective form of radon concentration. Through discussing the cause of the terrain interference effect in combination with an analysis of the measured ground radon and radium data, it is considered that the surface radon anomaly is mainly formed by the decay of nanometer ²³⁸U and ²²⁶Ra which is transported to the surface by relay transmission. In order to suppress the terrain interference, the authors adopted the subarea median contrast filtering method for radon concentration data processing, and the results show that, on the basis of retaining high anomalies, the weak abnormal information can be enhanced, and new ore-related anomalies can be delineated, which suggests that good application effect can be achieved.

Drill Hole ZDSD-1 is the third scientific drilling hole in the Luobusha chromite deposit,belonging to the "continental scientific drilling:site selection and pilot hole" project,and its final depth is 1486.86 m.The drill hole implemented continuous coring and conducted geophysical well logging.The ultrasonic image logging data contained a mass of information about the borehole wall geological features,which played an important role in the identification of fractures,fracture zones and the analysis of tectonic stress field.Using the ultrasonic image logging data,the authors found that most fractures exhibit the form of dark stripes whose width changes obviously,the fracture zones in most cases exhibit littery dark patches,while they assume a large area of dark stripes where the strata are broken seriously, and the borehole breakouts exhibit a pair of symmetrical dark straight stripes or patches spacing 180 degree.Through the statistics of the orientation for 20 pairs of borehole breakouts,the authors infer that the orientation of the maximum horizontal principal stress for drill hole ZDSD-1 is 40.3°~218.4°.

The basic principle and advantages of wide field electromagnetic methodhave been introduced. Deep geothermal resources in Nashanarea of Yizheng, Jiangsu province have been explored by way of wide field electromagnetic method,and identified the first hot water reservoir and second hot water reservoir which havebigoutput and high temperature.Results show that wide field electromagnetic method is an effective geophysical exploration method for deep geothermal energy resources.It has advantages of deepsurvey, high resolution, fast data acquisition and so on.Its exploration depth is more than 1 500 meters. So,it will become main geophysical exploration method for deep geothermal energy resources.

Ming Huazhen Formation is the main oil-bearing series in Oilfield in Bohai Huang Hekou sag. The oil and water sands of Bohai Huanghekou sag showed strong amplitude highlight characteristics, and difficult to distinguish from poststack and prestack attributes. This paper takes the A oilfield as an example and according to the seismic response characteristics of oil and gas in this area, the low frequency area of seismic data is taken as the maximum difference frequency of oil and gas, and the frequency domain is extracted. In the time domain, amplitude exponential weighted is applied to extracted seismic data, so the oil layer is characterized by bright spot characteristic. The bright spot directly indicates oil and gas, and then reaches the purpose of hydrocarbon detection. All the sand bodies within the target area were statistically analysed. The prediction accuracy of hydrocarbon bearing sand bodies in the shallow layer of A oilfield is increased from 69% to 86% with the bright spot attribute of hydrocarbon. In particular, the prediction accuracy of the water bearing sand bodies in the oilfield is increased from 63% to 96%,and solved the problem of oil water distinction and oil gas reservoir identification in A oilfield. This method not only improves the computational efficiency, but also solves the problem of the identification of oil and gas reservoirs in A oil field.

Drilling in limestone areas often meets karst caves, which may be a big risk. For the purpose of reducing the risk, the magnetotelluric sounding method can be used to detect the karst cave so as to determine the right drilling location. This paper describes the selection of right location of Ciye No. 1 well. By conducting magnetotelluric sounding in the well site, the area containing karst cave under the well site can be detected. Ciye No. 1 well was placed in the area without karst cave, and hence it doesn't meet karst cave during drilling. So, the place of Ciye No. 1 well selected by magnettelluric sounding is right. The right place ensures the safety of the drilling.

This paper briefly describes the basic principle of aeromagnetic compensation technology in three aspects, i.e., composition of plane interference field, establishment of the mathematical model, and solving model coefficients, and gives a review of the research history of domestic and foreign aeromagnetic compensation methods and aeromagnetic compensation instruments. Then, it compares two kinds of aeromagnetic compensation quality evaluation methods. On the basis of the analysis of aeromagnetic compensation technology research status, it analyzes and predicts the development trend of aeromagnetic compensation technologies.

This paper proposes an approach to prestack time migration in dip angle domain,which can produce common dip-angle imaging gathers directly.Dip angles and imaging area can be determined on these gathers.The final imaging profile is right without migration noise,which could improve signal-to-noise ratio.This scheme was applied to real data of the Matouying structure in Napu sag,and the good results demonstrate that the approach to prestack time migration in dip angle domain has broad application prospects for low signal-to-noise ratio and big noise area.

The main purpose of pre-stack seismic inversion lies in getting elastic parameters of underground media and then making liquid identification and reservoir description.In this paper the authors tried to eliminate the inherent trouble that long offset seismic data could not be used efficiently when the approximate Zoeppritz equation is adopted.The authors start with the Zoeppritz equation of P-wave and S-wave velocity and obtain the Zoeppritz equation of compressional and shear modulus.Then,with the new Zoeppritz equation,the authors start the direct compressional and shear modulus inversion based on the generalized linear inversion theory and apply the means to seismic data with all angles.Model and practical test shows that the method is stable and reasonable in obtaining the compressional and shear modulus,and can reduce the cumulative error which is caused by the common elastic inversion method.The result obtained by the authors provides good data basis for the liquid detection and identification.

Micro-resistivity imaging logging plays an important role in the reservoir evaluation and the study of sedimentary facies and structures. However, its measurement values are not calibrated exclusively. Besides, the utilization of shallow lateral well logging (LLS) or spherical focusing logging (SFL) data to calibrate micro-resistivity imaging logging values is not accurate enough. This paper introduces a basic principle of Linear Four-Probe and uses four-probe device (ST2258C) to prove its validity. Moreover, it presents a workflow to calibrate the resistivity of imaging logging.

In the past, adsorption property of the materials used in the soil gaseous mercury method was heterogeneous, and it was also easy to be polluted in the process of operation. The above problems have exerted adverse effect on the application of the method. The trap apparatus of soil gaseous mercury based on multi-layer pipes adsorption techniques combined with the enrichment apparatus has been developed in this study. The adsorption property is verified by standard gas sample analysis in the laboratory. The results show that the trap adsorption is good, the stability is high, and its test performance meets the need of various indicators. The field test in Zhaoguan geothermal system shows that the trap apparatus can absorb effectively trace gaseous mercury in soil gas, and the application effectiveness is good. The trap apparatus improves the techniques of enrichment and analysis of gaseous mercury in soil in geochemical exploration and has a good application prospect.

The elimination of 'whole airspace effect' is a difficult problem in electromagnetic exploration. Experts both in China and abroad have tried to solve this problem from such aspects as basic principle, data-processing and traverse employment; nevertheless, there exist problems like harsh condition for seeking solution, complicated calculation, difficulty in realizing technical aim and high cost. This paper puts forward a new train of thought in which shielding apparatus is employed to directly eliminate the whole airspace effect so as to approach ground-style survey. The corresponding device is developed, and the application method and examples are given. Practice shows that the result is satisfactory.

The static effect of the magnetotelluric sounding method is caused by stored charge on shallow layer electrical inhomogeneity by primary electric field. The induced second electric field caused by the accumulated charge is proportional to the primary electric field, and ratio coefficient K is only related to the electrical property of the underground media. The dielectric properties of the underground media are unchanged, and the K value is unchanged. Therefore, the method of artificial source is used to measure the total field of E_t in power supply; the induced electric field E₂ is measured in the off instantly, and then the proportion coefficient of K between the two data is calculated. K and measured electric field of the magnetotelluric sounding method are used to correct static effect, the finite element 2D MT forward modeling are employed to calculate the static effect produced by the underground electric uneven body, and K is used to correct static effect, thus achieving success. The results show that this method can effectively suppress the static effect and achieve the goal of static correction.

The accelerometer bias and the scale factor are sensitively influenced by temperature so that the precision of gradiometer measurement system is affected. The measurement equation is derived according to the principle of gravity gradiometer including the temperature coefficient of accelerometer bias and the scale factor. The values' range of scale factor coefficient of temperature is presented by assuming some parameters and analyzing the relation equation. Taking some accelerometers for example, the choice of two positive temperature coefficients and two negative temperature coefficients makes the total temperature coefficient fall from 15.255 ppm/℃ to 1.075 ppm/℃ and meets the demand of the temperature coefficient.

This paper describes the principle and method about using radio wave tunnel penetration method to evaluate fracturing effect,and presents area method for quantitative evaluation.In the case of sounding data of 3211S working surface of the Songzao coal mine,the author developed comparative research on radio wave attenuation coefficient contour maps before and after fracture.Area quantitative evaluation method put forward in this paper was used for quantitative evaluation of fracturing effect of 3211S working surface.In addition,fault geological data exposed by tunnel verified the reliability and accuracy of using area quantitative evaluation method.This evaluation method can effectively guide reasonable layout of two supplementary hydraulic fracturing holes,and optimize construction design scheme of coal seams hydraulic fracturing.Moreover,it can save a lot of design and construction cost,and produce good economic and social benefits.Radio wave tunnel penetration method has many advantages,such as maturity of geophysical method, simplicity of operator,portable instrument,and high accuracy of detection results.This method has been used to evaluate fracturing effect of mining faces of the same coal seam in underground coal mine and obtained good results.Hence it is worthy of popularization and application.

The existence of shale and complex pore structure leads to complexity of electric conductance law in shaly tight sandstone,making it extremely difficult to quantitatively evaluate resistivity and saturation of shaly tight sandstone reservoir.The key to reservoir resistivity evaluation is the accurate acquisition of Archie exponent.Many researchers have studied triple porosity exponent m,most of these researches focus on the impact of complex pore structure without taking shale affect into consideration.In this paper,based on Waxman-Smith shaly sandstone model and Aguilera triple porosity model,the authors propose a new triple porosity conducting model for shaly tight sandstone,which is composed of shale,fractures and non-connected vugs.In the model the effects of shale and complex pore structure on porosity exponent m are considered.By single factor analysis,it is found that triple porosity exponent m decreases as fracture porosity increases,increases as non-connected vug porosity increases,and decreases as shale content increases.The validation of experiment data proves that the proposed model can accurately describe the electrical conducting law of shaly tight sandstone and can quantitatively evaluate the porosity exponent m.

Inversion is an important tool for transient electromagnetic data interpretation. This paper proposes a novel weighing scheme with periodic vibration for roughness restriction based on the regularized optimization theory. The small weights make the models sensitive to reflecting parameters' great changes and thus it is easy to show the thin layer with low resistivity. The large weights distributed near small weights can make sure the continuity of the inversion results, which reduces the variety of the solution. Synthetic models show that this method has higher resolution for low resistivity thin layer than traditional ones and keeps the same resolution with traditional ones when inverting low resistivity large areas. In addition, this method converges stably and does not rely on a prior information about the ground structure, thus making sure its application in practice.

The voltage response(dB/dt)is wildly used in TEM in-loop configuration; nevertheless, for layered earth,it has several defects in solution, such as unique valued, dual-valued, undefined valued and overshoot and undershoot phenomena. It is hoped that field response has not these defects. So if we want to observe field response directly,SQUID or flux-gate sensor should be added. Therefore the process of transferred dB/dt should be available. Of course it has some other difficult problems in calculation, for examples: how to get the first electromagnetic field strength and applied apparent depth formula. This paper tackles those problems and has solved them.

To study the Situation changes and influencing factors of soil resistivity when different types of soil were polluted by petroleum hydrocarbon, miller soil box was used in the indoor pollution soil resistivity experimenton the four different types of soil. The results showed that the grit and fine sand resistivity decreased when they were invaded by petroleum hydrocarbons pollutants, and silt and clay soil resistivity increased when they were invaded by petroleum hydrocarbons pollutants, which showed the opposite trend.When moisture content was more than 30%, the change of moisture contenthardly influenced the soil resistivity, and then thedecisive factors were soiltype and the pollution level.Temperature is an important external environmental factors of soil resistivity.With the temperature rising, the polluted soil resistivity reduced, which conformedt campbell's empirical formula of amendatory parameters.

The quality inspection of tunnel lining based on the project, with some of the problems found in the process of GPR detection, lists the different geological conditions, the detection of tunnel lining, lining backfill compaction degree detection, steel detection, the typical radar image feature frame detection.