Vertical migration of hydrocarbon in underground oil and gas accumulation and its ring halo effect have been demonstrated is many oil and gas fields. On such a basis, oil and gas geochemical exploration methods with multi-indices and multi-parameters have been widely used in practical work. Nevertheless, the effects of geochemical exploration have not been always satisfactory, which may be attibuted mainly to the inadequate consideration of such factors as the complexity of natural conditions at surface, the diversity of oil and gas trap types and the diversity of geochemical anomaly patterns. In the past, good geochemical exploration results seemed quite easily obtained in areas where geological and surface geochemical conditions were comparatively simple, whereas it was rather difficult to gain achievements under complex conditions. Based on some examples of oil and gas geochemical exploration conducted by the authors in recent years,the present paper has summarized the methods for eliminating such interference factors as surface Indscape and media as well as the problems of discriminatiog ring halo anomalies from top anomalies.

Based on a study on the geochemical of the weathering system of regional rook-soil-stream sediments is the Ashele copper ore district ed its outskirts,the authors have found the following regularities:(1)Ca is the most active elements in study area, which has formed an alkaline carbonate geochemical barrier-caliche layer at the soil depth of 40-200cm;(2) different geoingical backgrounds play different roles is gaverning supergene activities of elements, and the behaviors of elemots in the background area are obviously different from their behaviors in the anomaly area; (3)from weathering rocks through soils to stream sediments,the modes of occurrence of Cu cad Zn change remarkably from the dominance of sulfide facies to the dominance of organic facies; (4)most indicator elements of copper mineralization are concentrated in stream sediments with grain size <0.5mm, and can mingrate 7 km along the drainage beyond the ore district.

Radon is the unique gaseous state element in natural redioactive uranium series. Much importance has been attached to its influence upon the health of human bodies, especially its relationship with lung cancer. Hence, it has become an important subject in the study of environmental protection. This paper describes the distribution regularity of radioactive elements and the migration of radon in the earth, and deals emphatically with the factors affecting radon in residence for the purpose of contributing to the prevention and control of radon danger,

This paper first points out the limitations of applying field test records and one-dimensional-spectral data to the analysis of seismic noise, and suggests frequency wave spectra(f-k spectra)to the analysis of seismic noise. Then, with practical examples,it deals in detail with the apPlication of f-k spectra in such aspects as the study of noise characteristics,the providing of optimum parameters for two-dimensional wave-filtering, and the analysis of geological effecters.field work parameters. practice shows that f-k spectra provide quantitative basis for the analysis attenuation of seismic noise, and are hence of some referential value in guiding field collection and data processing as well as raising the signal-to-noise ratio and resolution ratio of seismic data.

From the prerequisite that the frequency domain IP is equivalent to time domain IP,this paper discusses the requirements for precision of potential difference measurement when the IP response parameters must attain the necessary precision. The time domain IP does not require very high relative precision of potential difference, but the supply current is large and the equipment is cumbersome. The frequency-varying method needs very high relavtive precision of potential difference, which can hardly be attained when polarizability is low.The dual frequency IP can simultaneously measure dual frequency potential differences,and the value of potential diffetepce has very high relative precision, so that it can easily and satisfactorily meet the requirement for the precision.

The present paper describes some advances in the application of the magnetic exploration method to metallic deposits. Remarkable advances of magnetic exploration have been made in such aspects as the distinction between syngenetic deposits, epigenetic deposits, hydrothermal deposits and stratabound deposits,the determination of formation ages of ore deposits,the detection of ore sources,the evaluation of ore potential of rock bodies, and the prospecting for concealed orebodies. The magnetic exploration method has been proved to be a unique means in solving these problems.

This paper presents a new two-dimentional resistiving imaging method, namely resistivity tomcgraphic imaginery, and describes some supplying-receivipg ways for resistivity imagery.It takes advantage of the reverse projection technique of seismic wave and electromagnetic wave, and applies the reverse projection of resistivity combined with the utilization of routine algorithm (conductive center method for direct calculation and nonlinear least squares method for inverse revision)so as to carry out the reconstriction of two-dimensional resistivity image.Using Fortran language,the authors made programming for realizing the above process, and performed lots of digital simulation experiments and, as a result,obtained fairly good imaging effect.