Advanced Materials Research Vols. 962-965

Abstract: Different apparent resistivity exists many different characteristics, such as in terms of the speed of tending to real resistivity, the strength of oscillation sexual and the resolution. Aimed at the problem of how to select apparent resistivity in magnetotelluric (MT), this paper compares and analyzes the characteristics of different apparent resistivity in reflecting underground electrical structure by theoretical calculation formula and model calculation, and then summarizes the advantage and disadvantage of different apparent resistivity. The calculation results of several typical geoelectric models show that Basukur apparent resistivity is the best definition method of apparent resistivity, followed in turn, from good to bad, is the apparent resistivity defined by the real part of impedance, discount apparent resistivity, Cagniard apparent resistivity and the apparent resistivity defined by the impedance square module and the apparent resistivity defined by the imaginary part of impedance square, and the apparent resistivity defined by the imaginary part of impedance is the worst. this conclusions provide the judgment basis for practical application.

Abstract: The major rock types of Ordovician Majiagou Formation Ma5₄¹ Submember in western Jingbian Tableland include muddy dolomite, gypsum-bearing dolomite, gypsum dolomite, limy dolomite, and muddy powder crystal dolomite. This paper is based on the theory of sedimentary petrology and with the methodology of comprehensive mapping by using single factors to analyze multiple factors.Using stratum thickness, the content of gypsum and penecontemporaneous dolomite as single factors, we studied the lithofacies palaeogeography in Ma5₄¹ Submember.The results show that Ma5₄¹ is generally a set of sedimentation from supratidal limited evaporation environment and in the period of sea level decline with shallow water. The sedimentary microfacies are mainly composed of gypsum-bearing dolomitic flat and gypsum dolomitic flat ,dolomitic gypsum flat comes second. We combined the areas regional geological background with lithofacies palaeogeography to construct the limited evaporation tidal flat sedimentation maps of Ma5₄¹ Submember. Meanwhile,the control of reservoirs was studied. We thought that gypsum-bearing dolomitic flats and dolomitic flats provide a foundation for the development of large-area reservoirs.

Abstract: The 373 deposit,as a typical carbonanceous-siliceous-pelitic rock type uranium deposit,is rich in organic matter and pyrite.Close relationships exist between organic matter and uranium mineralization in a lot of uranium deposits. But few people have studied the relationship between uranium mineralization and organic matter of carbonanceous-siliceous-pelitic rock type uranium deposit.The organic matter type of 373 uranium deposit is type-II₂.The sources of organic matter are mainly marine plankton,microbial and terrestrial plant. The organic maturity is relatively low,at the immature-low mature stage.Compared with the surrounding rock ,the ore has gone through higher paletemperature on account of hydrothermal and fault. The type and the maturity of organic matter result in the generation of large amount of humic acid during thermal evolution that could be preserved in strata. The contents of chloroform bitumen “A” of organic matter in the mineralized layer are 0.47—10.42ug/g .Asphaltene is the main component of chloroform bitumen “A”.The correlation between chloroform bitumen “A” and uranium content is high,as well as the correlation between the content of asphaltene and uranium content. Study shows that the functions of organic matter in 373 uranium deposit are mainly adsorption,complexation and reduction.

Abstract: In the study of geological characteristics of digital, The original geological information come from different subjects and in different ways .The multiple heterogeneous causes that multivariate statistical analysis model depends on high-quality information encoding .This article discusses the information encoding of the qualitative geological data and puts forward a new encoding method which based on α tree structure. The method is characterized in following the geological spatial relationships and hierarchy principle. The error of the quantification theory IV model with this method is smaller and the approaching of spatial relations of geological unit is better. So it can be used in classification or prediction of geological unit (or variable).

Abstract: In this paper, four general directions are described to make evaluations and their resource potential; those are coal structure and coal level, gas content of deep coalbed, the coalbed thickness and distribution and the buried depth of coalbed. Coalfields of the study area are mainly Permian and Carboniferous coal seam of Shanxi Formation coal and Benxi group 11 # coal, coal seam depth 1370-1812m. No. 3 coal-seam average layer thickness of 1.6 m, the monolayer most 2 m thick; No. 11 coal-seam in the average layer thickness of 3 m, single-layer thickness of 4.5 m. Predict the amount of coal resources of 17.3 one hundred million t. Predict coal-bed methane resources of 27.68 billion cubic reserve abundance of 104 million square / km2 in. The exploration results show that this region has good development prospects.

Abstract: We introduce the differential evolution (DE) algorithm in the geophysical nonlinear inversion field. We set up a nonlinear inversion model of DC electrical sounding data using the DE algorithm. A comparison between the model and actual data suggests that the DE algorithm is more accurate and faster than existing algorithms. The study results presumably open new vistas in geophysical nonlinear inversion, and the DE algorithm may find application in two-dimensional or three-dimensional electrical sounding inversion. In the end, we applied the DE algorithm to the polymetallic ore exploration successfully in Inner Mongolia.

Abstract: On the base of drilling cores, summarizing some sedimentary facies marks, such as grain size characteristics, sedimentary structures, log curve, etc, it is analyzed the sedimentary characters of fan delta of Yingcheng formation in Lishu fault depression according to drilling well sedimentary analysis. The study area grows two subfacies, fan-delta plain and front fan-delta, existing 6 microfacies which are debris flow, distributary channels, interdistributary bay, submerged distributary channe, mouth bar and submerged distributary interchanne. Then the depositional model of gentle slope type fan delta is established.On the plane, fan delta existing in this area has characters of contiguous development and mixed-source deposition; In the longitudinal direction, deposition lithologic section developed in the period of water withdrawal is built on the retrograding lithologic section developed in the period of water inlet.

Abstract: The thrust fault plays an important role in the migration of oil and gas, etc. It can either block the oil and gas lateral migration, or become a good migration pathway. In order to have a more intuitive observation on forming process and study on the vital influential factors of it, the thick and extrusion stress of layers, such as laboratory with special designed experiment deviced by changing the above factors in the thrust fault structure formed by physical simulation experiments. The results show that the thrust fault formed in the basement, near the surrounding fold and associated fractures are associated with development, to a large extent influence the oil and gas migrate and storage. In this experiment, we simulated the process of thrust faults formed visually, providing a basis for predicting the observation analysis and associated folds and associated fracture development and distribution.

Abstract: Since the discovery of business flow in volcanic rocks of Yingcheng formation, the deep volcanic rocks of Songliao basin have become another advantaged target for oil-gas exploration. To reproduce the the development process of oil-gas generation, migration and accumulation, accurately calculating the oil-gas accumulation time is a very important work. To minimize the error, we must seriously study the regional tectonic evolution history and recover the eroded thickness. According to the actual situation of the study area, trend method can be used to recover the top eroded thickness of volcanic rocks in Yingcheng formation. Finally we get the maximum eroded thickness in the basin is between 120 m to 240 m, located in the southeastern basin.

Abstract: In the gravity anomaly dectection and the inversion of physical property, the parameters can reflect the characters and details of source. At the same time, it can enhance the resolution of the source. In this paper, gravity data from global 1-minute grids are applied to inverse the structure of Longmenshan fault zone, other small faluts, several active faults and geological stratum, the research area where is complex geologic region. The main goal of this paper is an attempt to interpret the gravity anomalies of faults in the Longmenshan Fault zones.