With the decrease in shallow mineral reserves, deep mineral resources have become the focus of exploration. Seismic exploration, renowned for its deep penetration and high spatial resolution and precision, stands as a primary technique in geophysical exploration. In comparison to traditional P-wave seismic exploration, multi-component seismic techniques offer the advantage of simultaneously acquiring P-wave and S-wave data, overcoming the limitations of single P-wave impedance in predicting lithology and enabling high-precision imaging of subsurface structures. Constrained by field survey costs, the reflection seismic illumination is lower and results in a poor signal-to-noise ratio of multi-component seismic data in metallic ore exploration, which poses great challenges in imaging converted S-waves. Based on the seismic and geological characteristics of metallic ores, this study conducts imaging research on metallic ore models through synthetic data and field multi-component seismic data from a copper–molybdenum mine in Inner Mongolia, China. The emphasis is given to PS-wave pre-stack time migration based on precisely sorting the commonly converted point so as to explore the feasibility and technical advantages of multi-component seismic exploration in metal mines. Synthetic data and field data testing demonstrate that PS-wave imaging contains more abundant structural and lithological information compared to PP-waves, indicating promising prospects for the application of multi-component seismic data in metallic ore exploration.

The permafrost regions of the Tibetan Plateau are distributed in the middle latitudes of China,where the gas hydrate is differ ent from the gas hydrate in sea area and polar permafrost area in existing environment and basic characteristics.The lack of effective exploration technology has become the major technical bottleneck that restricts the investigation and evaluation of natural gas hydrate resources in permafrost regions of China.Supported by National 863 Program,Special Research Project of Ministry of Land and Resources and National Special Project of Gas Hydrate,the authors studied the development of key technologies of natural gas hydrate exploration in the permafrost regions of China.The prorate exploration methods for China's terrestrial gas hydrate exploration in permafrost areas have been initially established,which include the high resolution seismic method,the audio magnetotelluric sounding technology,the ultra-deep ground penetrating radar (GPR) technology,geochemical exploration technology and integrated geophysical logging technology.The seismology and electromagnetism identifications of gas hydrate reservoir have been found,the effective index of hydrate geochemical exploration is optimized,and the logging identification technology and reservoir parameter evaluation technology of gas hydrate reservoir are developed.An effective combination method for geophysical and geochemical exploration and a comprehensive geophysical and geochemical exploration model have been tentatively established in permafrost regions.The favorable area of gas hydrate accumulation is predicted,and several gas hydrate reservoirs have been found in the well suggested by the authors,which shows that the validity of methods proposed by the authors are tentatively tested and applied.The research results have great significance for promoting the progress of gas hydrate exploration and for supporting the exploration and development of natural gas hydrate resources in permafrost regions of China.

Gemucuo surveying area is on the northern margin of central uplift belt in Qiangtang basin.The results of regional geological survey of natural gas hydrate indicate that the area is provided with relatively good external gas source condition,transport tectonic condition,permafrost condition,reservoir and storage condition for generating gas hydrate and the delineation of the gas hydrate favorable block.In order to study the seismic method suitable for detecting gas hydrate and to better search for the distribution area of gas hydrate in the permafrost area,the authors carried out exploration work and contrast experiment of shallow and mid deep seismic reflection.The test results show that the characteristics of geological structure and stratigraphic distribution reflected in the shallow and mid deep seismic reflection profile are similar,except for that fact that the resolution is higher and the detection depth is shallower on the shallow seismic section.According to the results of the seismic exploration,the geological structure map of the survey area is made.On the basis of the geological data and other geophysical and geochemical data in the surveying area in combination with the attributes of reflection from known natural gas hydrate reservoirs in Muli surveying area,favorable distribution areas of natural gas hydrate are predicted,and the proposal of verification hole position is put forward.

In order to cooperate with the exploration of natural gas hydrate resources,the authors conducted the validity of the experimental study of high precision seismic reflection method in Muli area for the detection of natural gas hydrate in 2010.192 receive channels,2 m group spacing,8 m shot spacing,and 24 folds were used in reflection seismic survey.60 Hz geophone string (with 6 geophones) each received channel received seismic wave in the form of point array.Excitation sources were explosives,shot depth was 3～ 4 m,and shot charge was 1.2 ～ 2.4 kg.The seismic sections obtained by the method possessed high S/N ratio and resolution as well as obvious structural form characteristics.On the basis of a comprehensive analysis and interpretation of reflection seismic,well logging and geological data,the enrichment zones of natural gas hydrate were explained and validated borehole location was determined.The detection results were verified by DK9 borehole drilling in 2013.The gas hydrate reservoirs with large thickness were found 450m southwest of DK3 borehole.Experimental results show that it is difficult to detect natural gas hydrate directly by seismic method in the lower gas hydrate content's area,but through a comprehensive analysis of geophysical,geochemical and geological data in combination with drilling data,the enrichment zones of natural gas hydrate can be detected by seismic exploration.

Three-component seismic technology has played an important role in energy exploration,and achieved remarkable geological effects.In seismic prospecting for metal ore,the three-component seismic is helpful to solve what kind of geological problems,experimental research about this respect has not been carried out.In order to discuss the detective effect of threecomponent seismic technology in metal mine exploration,we carry out the three-component seismic experiments of the Zhunsujihua CuMo mine in Inner Mongolia based on density and velocity test of drill core samples.The working methods of dynamite source simulating and single orthogonal 28 Hz three-component geophone receiving as well as multiple coverage are adopted in the trial.The p-wave and convened-wave seismic sections obtaining can be used to interpret through the processing of three-component seismic data.It can be seen that characteristics of wave group are more obvious on p-wave section,information amount are larger on converted-wave section through analysis of longitudinal wave and convened-wave seismic data.To interpret comprehensively both data is beneficial to interpretation of metal ore seismic data.The experimental seismic sections are explained using the geological data and the elastic parameters of rocks and minerals obtained.It can be inferred that the deep hidden metal can be searched in the NE side of outside No.8 geological section based on the characteristics of reflections of experimental seismic section.

新疆喀拉通克铜镍矿自1989年建成投产,已生产27年,属中度危机矿山.为探测该矿山深部资源,需要提供地质构造和隐伏含矿岩体的信息,为此开展了地震数值模拟和高精度反射地震研究.地震正演模拟结果为该区金属矿地震数据采集观测系统设计和实际地震资料的解释提供了依据,地震勘探获得的反射地震剖面分辨率高,成像清晰,能够对测区深部地质结构和构造及隐伏岩体进行可靠解释.地震剖面的地质解释得到了钻探验证,证实了深部含矿岩体的存在.该地震探测结果为在矿山寻找深部隐伏矿指提供了线索.

The Muli area is the only region where gas hydrates have been found in the mid-latitude permafrost regions of the world. The use of geophysical method and certain geophysical parameters have a strong predominance in identifying gas hydrates and optimizing the effective gas hydrate detection methods in hard rock permafrost areas. Since 2009, a series of tests has been performed in the Muli area, including seismic reflection and electromagnetic methods, and integrated geophysical well logging. The results show the presence of three types of gas hydrate reservoir, namely sandstone pore, mudstone fracture, and shale fracture types, with each showing a different well logging response. The gas hydrate reservoirs in the Muli area are characterized by high frequency and weak amplitude on the two-dimensional seismic profiles, and high horizontal resistivity on the electrical sections. The geophysical characteristics are complex, particularly as a result of the specific environments of gas hydrate reservoirs. These characteristics can be used to estimate the type and distribution of the gas hydrate reservoir, and to improve gas recovery rates by directing preliminary exploration.

The Rayleigh-wave method, which is based on the elastic layered system theory, is one of the most widely used techniques in environmental and engineering geophysics to determine shear-wave velocities and dynamic properties. Wave propagation in the Earth, however, has been recognized as viscoelastic. Therefore, it is important to study propagation characteristics of Rayleigh waves in viscoelastic layered media to improve surface wave exploration in the field. It is well known as the osculation phenomenon which causes two adjacent dispersion curves to get very close to each other in certain types of elastic layered models (e.g. in presence of low-velocity layers and strong impedance contrasts). However, there is no related research about this phenomenon in viscoelastic layered media. We introduce the Muller method to calculate the Rayleigh secular function in viscoelastic layered media. Based on the continuity of Rayleigh-wave dispersion and attenuation curves in layered media, we analyze the cross of Rayleigh-wave dispersion curves in normally dispersive two-layer models. Then we study the oscillation characteristics of Rayleigh-wave dispersion curves in the vicinity of "cross" points by eigendisplacement curves. Results demonstrate that the oscillation characteristics of Rayleigh waves have substantial differences in viscoelastic media compared with elastic media. Rayleigh-wave dispersion curves cross each other even in some normal models due to the effects of the increasingly strong dissipation in viscoelastic media, which does not occur in the elastic case.

Halahu is located in the Tibetan Plateau.The results of geological survey,AMT (Audio Magnetotelluric Sounding) and geo?chemical survey show that there is good perspective of natural gas hydrate prospecting in this area.High?precision seismic reflection ex?periments were carried out in search for natural gas hydrate in the area.1 200 receiving channels,2 m group spacing,1 m offset,8 m shot spacing,150 folds,the surveillance system excited in spread middle were used in reflection seismic survey.60 Hz geophone string ( with 6 geophones) was adopted,each received channel receiving seismic wave in the form of point array.Excitation source was large vehicle?borne Vibroseis.Instrument recording factors used included 0.5 ms sampling,2 s recording length and whole-band receiving.The high S/N ratio and resolution as well as obvious structural form characteristics were provided with seismic section obtained by the method.Vali?date hole location was determined according to land feature and the permafrost thickness,fault structure and high-speed distribution re?flected on seismic profile as well as other data.

The Zhunsujihua porphyry molybdenum deposit of Inner Mongolia is a medium sized metal deposits. Currently there is no deep drill hole data within the exploration area.In this study,high?precision seismic reflection measurement was conducted for detecting the deep metal deposits,ore?controlling structure and deep geological structure in the molybdenum ore district and its periphery.The re?flection seismic method of 2 sets of high power vibrator for stimulation,5 m group interval,960 receiving and 80 folds were used,and high?precision seismic reflection profiles which can reflect clearly deep geological structure was obtained.Ore?passage structure and ore?controlling structure,concealed rock mass distribution as well as cross?cutting relationships of rock masses of Variscan and Yanshan pe?riod can be clearly explained on the section.The deep crustal fluid migration paths and dynamic process are discussed.The prospecting target zone is delineated in search for concealed metal ore deposits in the area.

由于金属矿区地质构造的复杂性,地震反射方法在金属矿区的应用效果一般较差.为解决金属矿勘查中的方法技术问题,在内蒙古准苏吉花斑岩型钼矿床及其外围地区开展了地震层析成像和高精度反射地震联合勘探的方法技术研究.高精度反射地震采用2台套大功率可控震源激发,5m道间距,960道接收,80次水平叠加的工作方法;地震层析成像采用了1000道采集,10 m道间距,9990m接收排列长度,采用炸药震源激发,炮间距约2500m,最小炮检距10 m,最大炮检距10500m,采用排列中间或单边激发的相遇观测系统.两种探测方法均获得了能清晰反映深部地质结构和构造的反射地震和层析速度剖面.试验研究结果表明,地震层析成像不但可弥补反射地震资料在探测浅表层方面的不足,而且还可为反射地震资料偏移处理提供有用的速度信息,从而提高反射地震资料的处理效果;该联合勘探结果还为在该区寻找深部隐伏金属矿指明了新的找矿靶区.

Three?component seismic exploration is an effective method for the utilization of P?wave and converted?wave to detect fine structures.With this method,converted?wave imaging profiles have high resolution,and small geological structures such as small faults and small structures can be identified.In this paper,based on the application experiments of three?component seismic exploration tech?nology in Qiangtang basin of Tibet,the authors investigated the three?component seismic data acquisition method,converted?wave data processing technology and comparative interpretation method,and the results achieved prove the effectiveness of this method.This paper has certain reference value for the application and study of multi?component seismic exploration technology in plateau permafrost area in the future.

Due to complex seismic?geological conditions,it is very difficult to acquire high quality results of shallow seismic exploration in Qiangtang basin of Tibet. In this paper,through the experiment of shallow seismic exploration technology in this area,the authors dis?cussed the interference of the permafrost layer to the seismic data.In seismic data acquisition,a smaller channel spacing should be a?dopted,with a number of long arrangements of multi?channel receiving mode.In addition,the number of CDP stacking is increased,and a large tonnage high frequency vibrator is utilized for high?frequency excitation.In this way,a higher quality of raw seismic data can be obtained.In seismic data processing stage,we can use the corresponding de?noising technology before CDP stacking,which can effective?ly suppress various interference waves,such as random noise and coherent noise.The acquisition method and processing technology of 2?D shallow seismic survey is tentatively summarized,and the experimental study has achieved good results. The results achieved by the authors have certain reference value for application and study of shallow seismic exploration technology in plateau permafrost area in the future.

在金属矿地震勘探中,岩矿石弹性参数尤为重要.为更好地开展金属矿地震方法技术试验研究,本文对内蒙古准苏吉花矿区的钻孔岩心标本进行了密度和速度测试,在此基础上,开展了金属矿地震方法试验.根据获得的试验区岩矿石弹性参数测试结果,讨论了不同岩矿石的反射系数和速度与密度之间的关系.研究结果表明:花岗闪长岩(岩体)与变质粉砂岩(围岩)之间的反射系数较弱,不足以产生能够识别的反射信号.在花岗闪长岩(岩体)内部,闪长岩(脉)、矿化花岗闪长岩、铜钼矿体与花岗闪长岩之间具有较强的反射系数,能够产生可识别的反射波.铜钼矿化花岗闪长岩的密度较高,速度较低,表明在金属矿区,矿石的速度并不一定随密度的增加而增加.利用所获得岩矿石弹性参数和地质资料,对获得的试验地震剖面进行了解释,根据L2试验剖面上的地震波组特征,认为在该剖面以外NE一侧,有可能寻找到深部隐伏金属矿.

The physical samples of natural gas hydrate were obtained first by drilling in permafrost region of Qilian mountains of China in 2008. The validity experimental study of seismic reflection method in Muli region was carried out on the detection of natural gas hydrate in 2010. It is considered preliminary that reflections formed by natural gas hydrate media inside the fractured zone on seismic profile possess low velocity and low amplitude, high frequency characteristics, through comprehensive analyzing and interpretating the seismic and well log and geological data. According to the dynamic features of the reflection and logging results, anomalous part of natural gas hydrate found in the DK-4 and crystal segments of gas hydrate revealed in the DK-3 are analyzed. Analysis results do not support natural gas hydrate drilled in the DK-4. Combined with borehole data, the enrichment zones of natural gas hydrate are explained.

Buried mineral especially deep mineral exploration is very difficult to explore in wide of coverage area in China. The conventional methods do not play a big role, so prospecting must depend on science and technology. This article lists parts of the relative maturity of geophysical exploration achievements,such as the HTS magnetometer, array phase IP systern, phase induced polarization method, seismic survey for mineral etc. ,to summarize the method of characteristics, technical specifications,application examples and effects. These results can be used for prospecting as soon as possible.

2008年,在我国祁连山冻土区首次钻获天然气水合物实物样品.2010年,在木里地区开展了反射地震方法探测天然气水合物的有效性试验研究,通过综合分析解释反射地震和测井及地质资料,初步认为含天然气水合物介质形成的反射波在地震剖面上具有低速、弱振幅、高频的特征.根据反射波的这些动力学特征及测井结果,对在DK-4钻孔中见天然气水合物异常条带和在DK-3钻孔中揭示的含天然气水合物晶体区段进行了对比分析,分析结果不支持DK-4钻孔钻遇天然气水合物,并结合钻孔资料,推断解释了天然气水合物富集地带.

The physical samples of natural gas hydrate were obtained first by drilling in permafrost region of Qilian Mountain of China in 2008. Permafrost area in Qilian Mt. is located in lower latitudes at high altitude, and the samples form in the Jurassic stratum under hard rock environment, rather than in unconsolidated soil layer. The environment of the Gas hydrate discovered is different from in the Arctic region. The validity experimental study of seismic reflection method at Muli region in Qinghai province was carried out for detecting natural gas hydrate in 2010. High-precision seismic reflection method is used in the experimental study. Under the environment of high altitude and permafrost, the seismic survey is very difficult. The seismic data to be able to interpret is obtained through the hard work of field staff. It is considered preliminary that reflections formed from natural gas hydrate media on seismic profile possess low velocity and low amplitude, high frequency characteristics, through comprehensive analyzing and interpreting the seismic and well logging and geological data. According to the dynamic features of the reflections and logging results, anomaly segments of natural gas hydrate found in the DK-4 and crystal segments of gas hydrate revealed by the DK-3 borehole are analyzed. The analysis results do not support natural gas hydrate drilled in the DK-4. Combined with borehole data, the enrichment zones of the natural gas hydrate are inferred.