Chemical stratigraphy has been playing an increasingly important part in solving stratigraphical problems.Nevertheless,its inter-discipline characteristics such as multi-step, intricate technology and high cost present critical requirements to its researchers for their comprehensive qualifications such as structure of knowledge.Deficiency of any step would bring defects or mistakes to the test result and study reliability.These problems have already been exposed one by one in chemical stratigraphy in the past twenty years.Hence the guaranteeing of original characteristics of testing samples constitutes a most important problem. The research resources could be focused to the proper targets in the process of sampling in field work and the preparation of testing samples in indoor study. With the help of cathode luminescence,the disturbance of diagenesis could be excluded and eliminated eventually.How to verify the systematic errors of testing instruments and how to make the most of these testing data are also the crucial problems which should be solved.Owing to the characteristics of carbonatite,debris and fossil shells,there are still some weak points that should be strengthened in chemical stratigraphy studies.

Inorganic components, though not the basic components of oil and gas, are very intimately connected with the formation and migration of oil-gas hydrocarbon. Hence the analysis and study of associated elements in the oil and gas field make up an effective geochemical method in search for oil and gas. Studies show that the effective trace element indices in oil and gas evaluation are mainly Hg, V/Ni, V/Fe and subordinately N/Org.C, Pb and U. Trace element anomalies for oil and gas geochemical exploration are in the ring form, with the low value area over the oil and gas accumulation and the high value anomalous area on the edge of the oil and gas accumulation.

Gold geochemical characteristics of Shijiba area are controlled by strata, structures and dykes developed along structures, and the major element association of stream sediment and soil anomalies is composed of Au, Hg, As and Sb. According to geological characteristics and backgrounds of different units, different anomaly thresholds were selected to delineate anomalies.Gold anomalies are characterized by large sizes, high peak values, good concentration zoning and obvious concentration centers. Engineering exposure and inspection of quite a few anomaly concentration positions led to the discovery of gold ore bodies with considerable sizes and grades, which formed Yanshan (large-sized), Xinguan (medium-sized), Houdouwan (small-sized) and Guanniuwan (small-sized) gold deposits. Ore bodies are quite consistent with anomalies, suggesting that stream sediment survey and soil survey are reliable and effective methods in this area. Based on contrast and analysis, the author holds that it is necessary to study and verify other anomalies and "weak anomalies", which may lead to the discovery of other gold deposits in this area.

he most prominent advantage of the heavy magnetic information is its deep penetrability, which can detect deep geological and structural characteristics. Therefore, the method has been widely used in basic geological research and resource evaluation as well as in the investigation of basement undulation below the thick cover layer and the deduction of deep structures and geological bodies (including invaded bodies and mineralized bodies). The key of the application of the heavy magnetic information lies in setting up a set of standards to deduce the possible material composition, size and burial depth of the geological body as well as its relationship with mineralization. Based on the data of the Nannihu molybdenum mine in East Qinling Mountains, the authors tried to deduce the mineralization possibility in the same geological-structural unit. The combination of geophysical and geochemical information led to the discovery of a new molybdenum polymetallic deposit.

The IP method based on the difference in the polarizability and resistivity of rocks has played an important role in the exploration of concealed and deep ore bodies. This paper points out that, with the IP sounding, the medium-gradient array can find and delineate IP anomalies and detect the burial depth and spatial occurrence of polarized bodies, thus providing fairly sufficient basis for engineering verification. The combined methods also played an important role in search for large-sized lead-zinc-silver polymetallic ore deposits in Caijiaying and Beichagoumen of Hebei Province.

The De'erni copper and cobalt ore deposit was found in the 1950's and has been explored since then. Nevertheless, no breakthrough has been achieved near the main ore body. It is hence necessary to find some effective geophysical methods to solve the difficulty. By means of numerical calculation and field test, this paper deals with the availability of TEM in detecting underground ore bodies. Tests with TEM show that strong anomalies appear over massive copper-bearing pyrite ore bodies, and low resistivity is obvious on the cross section through inversion. Based on these achievements, the authors consider that TEM is a useful method in search for ore bodies in the vicinity of known ore deposits.

A metal cased well is chosen as the current electrode of resistivity tomography with a vertical line current source (RTVLCS), which greatly deepens the depth detection of resistivity tomography and improves the resolution of resistivity tomogram. RTVLCS can be carried out during the course of oil production, and using the apparent resistivity data acquired by this technique and inverse computation, the true resistivity of a target layer can be obtained, then the distribution of residual oil saturation via the relationship of resistivity and oil (or water) saturation. Analyzed our result with these from geological analysis, tracer detection method and rock core analysis and so on, it could provide an important reference for drawing up a plan of oil production. At last the goals of stable and increasing oil production can be achieved. In the present paper, RTVLCS has been tested in a mid-or post-phase oil region of an oilfield, and the distribution of residual oil saturation in its target stratum has been obtained. Compared this result with the distribution of the observed water saturation of each well in the oil region during the course of the measurement of resistivity tomography, it is found that the residual oil saturation obtained by this technique is reliable, which can be taken as the important reference of drawing up a plan for oil production in the mid-or post-phase of an oilfield. Therefore, RTVLCS has great application potentiality.

The authors studied the 1:200000 regional gravity anomalies distributed along the lead-zinc-(copper) ore belt in the Weining-Hezhang-Nayong-Zhijin-Shuicheng area of northwestern Guizhou as well as their corresponding relationships with geological, structural, rock body and geochemical anomalies. The results are helpful to the research on the metallogenic regularity, ore-forming positions and mineralization characteristics of this kind of ore deposits. Some suggestions concerning further ore-prospecting work are put forward in this paper.

An approximate kinetic equation describing an object following a near-circular ellipse trajectory is given in Lhis paper. Based on the orbit parameter of the GRACE satellites and under the condition that no consideration was given to the disturbance acting on the satellites, the authors calculated the distance, the relative velocity, and the inclination of the twin satellites, and analyzed their influence on the K-band ranging system. Theoretical analysis shows that the double frequency effect of the ellipse orbit could help to test the distance and velocity measurement of the K-band ranging system in orbit, which is of significance in the research and development of the K-band ranging system.

The measurement means of borehole acoustic CT technical system, data acquisition, data preprocessing and some forward and inverse methods are recounted in this paper, with some examples given concerning engineering survey and oil-gas field development and exploration. It is shown that the method of borehole acoustic wave CT is effective in detecting the position and the form of the target, and that the technique of borehole acoustic wave CT as a subtle exploration method has development potential and application prospects.

The calculation of the lower limit of the geochemical anomaly and the map compilation are of key and basic importance in the interpretation and appraisal of geochemical anomaly.This paper deals with the determination of the threshold of the geochemical anomaly with VBA programming based on average value and two times of standard deviation,and the method for direct compilation of the discrete point position map with MapGIS.The VBA and MapGIS were combined with each other and applied on the basis of the authors' experience, with satisfactory result obtained. It is pointed out that VBA and MapGIS have wide application prospects in geology and mining industry.

The key of searching for carbonate reservoirs is to find large water-eroded caves filled with liquids. The AVO analysis can identify the nature of the cavern filling in the Tahe Oil Field. Where the water-eroded cave filler is liquid, it has intense S-wave. This is because the S-wave can not be spread in liquids, hence the cavity boundary is the absolute reflection of S-wave. In other words, where the cavity filler is liquid, it has intense reflection of S-wave and P-wave. The AVO technique can thus be used to obtain elastic inversion data. The S-wave attributes can be extracted and the water-eroded cave filled with liquids can be identified.

The discovery of the Jinsha Ruins in Chengdu in 2001 is a significant discovery following the discovery of Sanxingdui, and is very important in China's archaeological discoveries in the new century. The discovery has unveiled the veil of the ancient civilization in West Sichuan Plain, filled in many gaps of Chinese archaeology, and provided a lot of scientific evidence for Yangtze River civilization. This paper deals with the application of the GPR method to detecting underground cultural relics, cultural layer and heritage in Jinsha Ruins. The research results are in accord with the excavation results, and confirm the application results of the GPR method in archaeological science.

This paper describes the present situation of the test techniques for hydrocarbon indices in sediment samples of marine oil and gas geochemical exploration, which includes sample collection, test techniques for light hydrocarbon and heavy hydrocarbon and the in-situ analytical and test techniques. The major existing problems are analyzed, and the development orientation of the test techniques for hydrocarbon indices in sediment samples of marine oil and gas geochemical exploration in future is discussed.

The utilization of more and more long-distance and large-capacity DC transmission circuits has made rather remarkable influence on magnetic survey in near-circuit areas. This paper describes the structure of the DC transmission circuit, characteristics of circuit magnetic fields and their effects on the ore-prospecting magnetic survey. The features of DC transmission circuit magnetic field in the magnetic map are also discussed. Some examples illustrating the effects of the DC transmission circuit are also given in this paper.

Based on the datum value and heavy metal content of surface soil, the authors made an evaluation of the pollution degree of surface soil in the city proper of Luoyang. Accelerating human activities and industrialization have caused heavier and heavier environmental pollution and increasing degeneration of soil quality. Modern industrial production and ancient human activities seem to be the main factors responsible for local severe pollution in the city proper of Luoyang, whereas natural geological actions have been very insignificant.

Based on data available in China and abroad, the authors have made a comparative analysis and study of the water quality characteristics of rainfall runoff on roofing of different construction materials and road surface of different materials, pointed out three major factors affecting water quality of urban rainfall runoff, and dealt with the practical significance of collecting and utilizing urban rainwater.

Airborne gamma-ray spectrometry has been widely used. To ensure the measuring quality of airborne gamma-ray spectrometry, we need to calibrate instruments regularly. However, very insufficient attention has been paid to the evaluation of the radiation dose received by workers. This paper evaluates personal radiation dose of the worker of airborne gamma-ray spectrometry according to the dose rate data recorded during the instrument calibration and experiments, and compares it with doses of other activities so as to reflect the radiation level.

This paper summarized two kinds of transfer matrix methods for calculating dispersion curves of Rayleigh waves. Some dispersion curves of layered models were calculated by the two methods so as to find characteristics of these methods. Calculation shows that the two kinds of results are in accordance with each other. However, the fast scalar transfer matrix method is faster than the transfer matrix methods deduced from Abo-zena, Menke, Bixing Zhang etc., and its stability and precision are better than the deduced methods. Nevertheless, in the aspect of avoiding numerical overflow in high frequencies, the transfer matrix algorithm is better than the fast scalar transfer matrix method.

In conventional pseudo-spectral method for solving the wave equation, the routine algorithm needs large quantities of computation and spends a long computing time. In this paper, the authors have integrated the pseudo-spectral method to raise the accuracy and efficiency, and improved its conventional algorithm of calculation constants which need multiple calculations in the Fourier transform and inverse transform in the procedure of calculation. These constants are brought out of the time loop structure, thus avoiding the duplication of many calculations and reducing the number of calculations. In this way, the computational efficiency has at least been doubled. Considering the importance of subtle traps in the oil and gas exploration, the authors have constructed a special structure for the subtle traps, namely the lens model. This algorithm was used to simulate cross-well field characteristics of high-velocity and low-velocity lens models and make a comparative analysis of synthetic cross-well seismic records, time slices and amplitude characteristics of the two models. The result is in good agreement with that of theoretical analysis.

In the processing of seismic data, the technique of well-controled seismic data processing can be used. The steps include obtaining spherical spreading compensation factors and Q compensation factors from well data, scanning around the obtained Q values, and then making an analysis by matching the well data with the migration profiles that are processed by different Q values. Finally, an accurate Q value is obtained. The results of true amplitude recovery and Q compensation of the actual data show that this technique is effective.

On the slope areas of the eastern and western sides of Damintun basin in the Liaohe oilfield, the underground structure is complex, and the dip angle is rather steep. The migration location effect cannot be satisfactorily obtained by prestack time migration. The authors used the prestack time migration method adapted to this region and also studied the selection means for migration parameters, such as the construction of the migration velocity model and the choice of migration apertures and dip angles. The results are fairly satisfactory.

This paper deals with the layer response characteristics of VES (Schlumberger configuration) and TEM (central loop configuration) through the forward modeling procedure, and the results show that TEM is more sensitive to the low resistivity layer and VES is more sensitive to the high resistivity layer. Based on the response characteristics, the paper then tried to do inversion of combined VES and TEM data, and the model inversion trial indicates that the inversion result is better than the result of single TEM or VES data inversion.

Data management and contour mapping using MapInfo and Surfer in regional gravity information system are dealt with in this paper. System development and running shows that the secondary co-development of MapInfo and Surfer is actual.

The conversion of the quantities, units and formulae in electromagnetism between the Gauss System and the International Unit System is rather complicated, and there may occur some errors in the units of some derived quantities. For this, the author has made some explanations in this paper.

In view of the limitation of engineering exploration in investigating the shallow geological structure, this paper proposes combining the SH wave reflection method with the multi-channel transient surface wave method to enhance exploration reliability and precision. With three practical examples, this paper points out several problems that are worthy of much attention during data acquisition and processing.