Advanced Materials Research Vols. 962-965

Abstract: Coal reservoir system is the key factors influencing the permeability of coal seam, the study of the development extent of the fracture is very beneficial for the large-scale commercial exploitation of coalbed methane. From the metamorphic degree of coal rock, maceral, coal characteristics and mineral filling these aspects ,this article discusses the control mechanism of the fracture system development. It is pointed out that the development degree of system is the direct factors influencing the coal reservoir permeability and fracture system development is influenced by many factors. The fillings in crack can block the fracture and reduce the permeability of coal reservoirs.

Abstract: Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the concentrations of rare earth elements and yttrium (REY) in coal and associated rock samples from the Guanbanwusu Mine, Jungar Coalfield, Northern China. The Guanbanwusu coals have a similar vitrinite reflectance and sulfur content, and a slightly higher ash yield. The concentration of REY (from La to Lu plus Y) in the 6 coal of the Guanbanwusu Mine varies from 72 μg/g to 396 μg/g and averages 186 μg/g, higher than that in normal Chinese coal (136 μg/g) and much higher than that in average world hard coals. The H-type distribution patterns in the No. 6 coal (W9-2 and W9-9) were probably caused by stronger water influences than those in the other coalfield. The coal bench (W2 and W9) with L-type is because terrigenous input influence.

Abstract: Phosphorites of the uppermost Neoproterozoic Doushantuo Formation were exposed at Weng'an, South China. Here, We report the origin of organic matter and paleoceanographic conditions of the fossil-bearing phosphorites at Weng'an, in terms of sedimentary facies, biomineralization and organic geochemistry, including the biomarker feature. GC-MS analysis showed that a normal alkane distribution pattern with a wide range of carbon atom numbers; Terpane, isoprenoids and steranes were detected in phosphorite. The biomarker implied that the sources of organic matters were the eukaryotes of phototrophic multicellular algae, protests and bacteria. Ph and Pr derivatived from Chlorophyll-a suggested that there may exist a photosynthetic process in palaeoocean. The result shows that phosphorite at Weng 'an generated from biomineralization. In summary, the evidence suggests microorganism were the major contributors to organic matter deposited as part of phosphorite, and exist biomineralization.

Abstract: This document studies the deposition condition in northeast Jizhong depression by using relevant data of cores, logging and scanning electron microscope. The result indicates that the study area has 7 kinds of lithofacies, including conglomerate, sandstone, siltstone, mudstone, bauxite, carbonate rock and coal seam . Bottom-up development in the study area cover tidal flat, lagoon, delta, meandering river and braided river, a total of five kinds of sedimentary facies. Benxi Formation, Taiyuan Formation and Shanxi Formation deposited in transitional facies, which has high generation potential of Hydrocarbon. Lower and upper Shihezi Formation is mainly a set of river deposition as a good reservoir. The top of upper Shihezi Formation and Shiqianfen Formation are mainly mudstone, which is conducive to seal oil and gas.

Abstract: The Huangshanxi sulfide-bearing intrusion, is located in the centre segment of Tudun-Huangshan-Jing`erquan-Tulargen mafic-ultramafic rock belt, the eastern part of the North Tianshan, controlled by the Kangurtag-Huangshan ductile sheer zone, and it is a multiple intrusion which composes of lherzolite, amphibole peridotite, wehrlite, pyroxenite, norite, gabbro, and diorite. The disseminated sulfides and sideronitic sulfides are the mainly ore types, the scale of the ore body is large and the grade is stable relatively. The total concentration of platinum-group elements (PGEs) in rocks and ores is very low, which average value is 0.93ppb and 8.8ppb respectively and it increases with sulfur content increases in ores. The PGE concentration appeared two peaks in the range of 200~300m and 880~980m depth in the drill core, consistent with the content of the sulfides. Rocks and ores samples have similar mantle-normalized PGE patterns which are shown as the PGE flat and slightly fall to the left, and the lower fractionation between IPGE and PPGE. The primitive magma may be the high MgO tholeiitic magma which should be undepleted in PGE and derived from partial melting of a metasomatized mantle source. Compared with continental tholeiite, simulating result reveals that the parental magma is visibly depleted in PGE, possibly duing to the sulfide pre-segregation of initial magma in deep crust. The platinum-group elements geochemical characteristics and petrochemical data show that the crustal contamination and the fractionation of olivine and pyroxene may be the main factors leading to S-saturation and sulfide segregation in deep crust.

Abstract: CO₂ injection into coal seams can not only enhance coalbed methane recovery (ECBM), but also reduce greenhouse gas emission into atmosphere. This paper describes some factors affecting CBM primary production, ECBM recovery and CO₂ sequestration in coal seams; and calculates CBM recovery quantity with primary production, the ECBM recovery potential quantity and CO₂ sequestration capacity in coal seams of West Henan Province. The results show that CBM primary and ECBM recovery potential quantity are estimated to be over 2147.278 and 1656.217 Gm³. The prediction also indicates that CO₂ sequestration potential quantity is about 3233.79 Gm³.

Abstract: Multiple-point statistics (MPS) is not only integrated the merits of pixel-based and object-based modeling algorithms, but it precisely describes reservoirs complicated steric configurations and geometrical form. Taking L1V formation of W offshore oilfield as an example, to resolve the problem of simulation time-consuming and large memory footprint under large training image and data template in MPS modelling, stochastic simulation of the reservoir has been established by using the new MPS Filtersim method. In this paper, the basic principles of MPS Filtersim algorithm and its application in research area are briefly introduced . According to the microfacies map in research area, training image can be established and the reservoir sedimentary facies model constrained by well-logging data can be built in SGeMS with Filtersim method. The research result shows that this algorithm requires less memory storage and can not only describe the distribution of channel, overbank and the interlayers rapidly and correctly,but it reproduces the spatial distribution law of reservoirs accurately.

Abstract: Logging response characteristic of organic carbon in shale and the commonly used method to evaluate the organic carbon quantitatively are introduced in this paper, and each method is used in different targets to simply analysis it’s suitability and influencing factor. The evaluating methods contain acoustic-resistivity separation method, CARBOLOG method, artificial neural network and C/O logging method, nuclear magnetic resonance (NMR) and other new methods.By comparative study, the calculated results of improved ΔlogR is more accuracy, this method can be used widely.The calculated results of C/O method needn't to be corrected in theory, so there is a strong feasibility of this method.When it is hard to use explicit function equation to calculate, the Artificial Neural Network method Shows great advantages and is able to compensate for the shortage of traditional methods.

Abstract: Based on the study of drilling, well logging and seismic profile, the Jurassic strata of the study area can be divided in to 2 2^nd-order and 4 3^rd-order sequences. The same formation in different regions unevenly distributed in study area due to sedimentary environment, sedimentary palaeotopography, post-depositional uplift and different degree of erosion. 4 3rd-order sequence boundaries can be recognized in this study, the results shown that the sequence boundaries used to be on the abrupt change point of the logging curve and are characterized by the bottom of large size braided channel scouring.

Abstract: It has become the focus of debate about Coalbed Methane (CBM) concept whether the surrounding rock is reservoir. The gas content of surrounding rock is considerable, and it may become valuable exploration targets. In lateral, the gas content of surrounding rock is negatively related with coal bed. In vertical, the closer distance between coal seam and surrounding rock is, the higher gas content is. The broad CBM is defined as the gas that mainly originates from coal, mainly exists in the coal seam, and also widely exists in the surrounding rock. The method of volume and capacity are used to resource calculation.