Advanced Materials Research Vols. 734-737

Abstract: The Saidu gold deposit is located in the northwest part of Ertix Tectonic Zone in Xinjiang. The ore bodies occur in altered mylonite zones within the Mar-kakol giant fault zone and are controlled by the ductile shear zone. The structural-metallogenic fluids of the early stage are characterized by mesothermal-hydrothermal CO₂-N₂-rich fluids, with homogenization temperatures of fluid inclusions being 252~408°C. The tectonic-metallogenic fluids at the middle stage are characterized by CO₂-H₂O fluids, with homogenization temperatures being 203~326°C. The fluids at the late stage were epithermal-mesothermal low salinity aqueous solutions, with homogenization temperatures being 120~221°C. The main gold mineralization was related to the post-orogenic extension environment, with the evolution characteristics corresponding to the evolution of shear zones.

Abstract: Western Tianshan High-pressure (HP)-metamorphic belt is characterized by developed High-pressure (HP) veins, which are composed by HP-metamorphic minerals. The host rocks of the HP-veins are mainly composed by eclogites and blueschists. As the direct record of the deep fluids in the paleo-subduction zones, the HP-veins can provide us deep samples for probing into the deep fluids in the subduction zones. Fluids in the deep subduction zones play an important role in crust-mantle exchange related to plate subduction process. The electron microprobe analyses of HP-metamorphic minerals omphacite inside the veins and host rocks in western Tianshan high-pressure metamorphic belt is mostly paid attention. The result shows that the composition of the omphacite from HP-veins have the same composition of the omphacite from the host rocks, which indicates that the fluids from which the HP-vein precipitated originated from the host rock.

Abstract: Volcanic lithology and lithofacies are important factors to control the formation of volcanic reservoir. It is a challenge for geologists and petrophysicist to identify lithofacies in the borehole by using well logs. According to the reservoir characters of Daqing volcanic reservoir in Songliao basin, five lithofacies and fifteen su-facies have been recognized through the drilled core analysis of lithology, texture and structure. The relationship between conventional well logs and volcanic lithology can be established by calibrating with core analysis which can be used to identify the rock composition by the established cross-plots. From the FMI measurement, the differences of resistivity values caused by volcanic rock texture and structure can be showed in the image clearly. It shows that four kinds of textures and five kinds of structure can be identified with FMI image. As the volcanic lithofacies marks, specific volcanics lithology, texture and structure corresponds to the specific lithofacies and sub-facies. So lithofacies distribution can be evaluated effectively with the model of volcanics texture and structure combined with rock composition. The results of study indicate that the composition, texture and structure characteristics of the volcanics can be identified by conventional log with FMI measurement, which is important to the further volcanic reservoir exploration and production.

Abstract: A total of two third-order sequences are subdivided in Late Permian. Sequence 1 is from the bottom of the Longtan Formation to the bottom of C₁₆ coal in Longtan Formation,representing a transgressive to regressive cycle,and the Sequence 2 is from the bottom of C₁₆ coal in Longtan formation to the top of the Changxing Formation. From Maokou formation to the first flooding surface (the bottom of the C₂₅) is the low systems tract in sequence 1(the earlier stage of coal accumulation). The palaeogeographic map has been reconstructed based on the contour maps of a variety of palaeogeographic parameters including total thickness of strata,thickness of sandstone,thickness of mudstone,and sandstone-mudstone ratio. The paleogeographic units include lowlandhighland eluvial plain and bay-lagoon-tidal. The transgression comes from south and the sediment provenances are mainly from the Kangdian old land in the west.

Abstract: To analyze the mining effect to gas permeability of tectonic soft coal seam, we choose typical sample from tectonic soft coal, study the gas permeability and microstructure. The results suggest that tectonic soft coal has been badly destroyed, and its micro fracture pore develops. Confining pressure has a great influence on the permeability of tectonic soft coal. When gas pressure remains constant, with the increase of confining pressure of tectonic soft coal permeability began to decrease very fast. But when decreasing to a certain degree, it changes slowly; when confining pressure remains constant, with the increase of gas pressure, permeability of tectonic soft coal first decreases and then increases. Under the condition of low gas pressure, tectonic soft coal permeability shows a significant Klinkenberg effect.

Abstract: According to the tectonic movement occurring in the South China Sea since the late Miocene and the sea level changes in Yingqiong Basin, Pearl River Mouth Basin, and global, combining with seismic reflection terminate characteristics, we divided Shenhu gas hydrate survey areas Pliocene strata into four sequences. According to the basic principles of the "outside-shape, internal-structure ,from seismic wave external geometry, supplemented by seismic physical attributes (amplitude, frequency, consistence),we identified the fill, mound, sheet, lens, sheet shape, wedge-shaped 6 categories, a total of 19 kinds of seismic facies in the study area. Contrasting to the drilling gas hydrate depth, the gas hydrate is mainly enriched around the slump deposits.

Abstract: The development of shale gas can influence the land use and exacerbate the problem of land use. The drilling and fracturing of a well need a large well site. Taking all the coverage of road building, platforms and pipelines into account, the average coverage of every well is near 16.2 hectares. More than 80 shale gas wells have been drilled and covered 1296 hectares. According to the development plan of shale gas of China, more than 300 shale gas wells will be drilled and will occupy 6156 hectares land to 2015. To the end of 2020, about 1.6~1.7×10⁴ shale gas wells will have been drilled and 27.54×10⁴ hectares land will be occupied. The quality of land is damaged during the process of shale gas development, lowering the soil fertility and making the land reclamation more difficult. During the process of shale gas development, the assessment and supervision and management system of land use should be reinforced and land use and reclamation should be reasonably planned. The efficiency and sustainability of land use can be improved by technology innovation of well drilling.

Abstract: 3D Geological modeling technique can apply the existing data comprehensively, representing geological structure intuitively, so further the research has significant meaning on this basis. This article constructs the 3D layered model and ore grade model of the sulfide deposit based on exploration data and geological knowledge. In order to estimate precisely the amount of mineral resources depending on the ore grade model, which has been built by the constraint layer, this method can improve the calculation.

Abstract: On the basis of predecessors study, this paper found that outbreak frequency of mantle plume is increase, while scale is reduce. The mantle plume provides ore-forming minerals to orogenic gold deposits, as well as affords force to supercontinent formation and decomposition, for the more controls the global tectonic. Supercontinent is the movement of upper crust that could be cause by combine factors of cold and heat mantle plume. Supercontinent supply suitable tectonic environment for orogenic gold deposits. Further, we discuss the relationship between mantle plume, supercontinent and orogenic gold deposit on space and time. With the evolution of the earth, especially the energy loss, the frequency of orogenic gold mineralization is increasing, while the scale is reducing.

Abstract: It is difficult to discriminate the lithology of complex lithological profile which contains lava, terrigenous sedimentary rock and volcanic transitional lithology by using conventional logging curves. Attributing to different kinds of lithology, different logging items have different reflecting abilities. Based on the 500 Hailar Basin complex lithology samples, we’ve made logging response cross plots of resistivity and radioactive curves, porosity and resistivity curves, porosity curves and radioactive curves to identify the sensitive feature of logging response among different lithologies. The research provides the basis for fine evaluation of complex lithology profile by using the well logging data.