Lanzhou Testing and Quality Supervision Center for Geological and Mineral Products

Lanzhou, China

Lanzhou Testing and Quality Supervision Center for Geological and Mineral Products

Lanzhou, China
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Tang J.,Hangzhou Dianzi University | Yin H.,Hangzhou Dianzi University | Wang G.,Sinopec | Chen Y.,Lanzhou Testing and Quality Supervision Center for Geological and Mineral Products
Applied Geochemistry | Year: 2010

Methane microseepage is the result of natural gas migration from subsurface hydrocarbon accumulations to the Earth's surface, and it is quite common in commercial petroleum fields. While the role of microseepage as a pathfinder in petroleum exploration has been known for about 80a, its significance as an atmospheric CH4 source has only recently been studied, and flux data are currently available only in the USA and Europe. With the aim of increasing the global data-set and better understanding flux magnitudes and variabilities, microseepage is now being extensively studied in China. A static flux chamber method was recently applied to study microseepage emissions into the atmosphere in four different sectors of the Yakela condensed gas field in Tarim Basin, Xinjiang, China, and specifically in: (a) a faulted sector, across the Luntai fault systems; (b) an oil-water interface sector, at the northern margin of the field; (c) an oil-gas interface sector, in the middle of the field; (d) an external area, outside the northern gas field boundaries. The results show that positive CH4 fluxes are pervasive in all sectors and therefore, only part of the CH4 migrating from the deep oil-gas reservoirs is consumed in the soil by methanotrophic oxidation. The intensity of gas seepage seems to be controlled by subsurface geologic settings and lateral variabilities of natural gas pressure in the condensed gas field. The highest CH4 fluxes, up to ∼14mgm-2d-1 (mean of 7.55mgm-2d-1) with higher spatial variability (standard deviation, σ: 2.58mgm-2d-1), occur in the Luntai fault sector. Merhane flux was lower in the oil-water area (mean of 0.53mgm-2d-1) and the external area (mean of 1.55mgm-2d-1), and at the intermediate level in the gas-oil sector (mean of 2.89mgm-2d-1). These values are consistent with microseepage data reported for petroleum basins in the USA and Europe. The build-up of methane concentration in the flux chambers is always coupled with an enrichment of 13C, from δ13C1 of -46‰ to -42.5‰ (VPDB), which demonstrates that seeping methane is thermogenic, as that occurring in the deep Yakela reservoir. Daily variations of microseepage are very low, with minima in the afternoon, corresponding to higher soil temperature (and higher methanotrophic consumption), and maxima in the early morning (when soil temperatures are lowest). A preliminary and rough estimate of the total amount of CH4 exhaled from the Yakela field is in the order of 102tonnesa-1.The present data can statistically improve the accuracy of the global microseepage flux data-set, but further surveys are needed in order to understand the frequency of occurrence and spatial variability of positive CH4 fluxes in soils over petroleum fields. © 2010 Elsevier Ltd.


Liu J.-B.,Lanzhou Testing and Quality Supervision Center for Geological and Mineral Products | Wu Y.-Z.,Lanzhou Testing and Quality Supervision Center for Geological and Mineral Products
Yejin Fenxi/Metallurgical Analysis | Year: 2013

The medium, low and trace tin in ore were measured on atomic emission spectrometer by selecting several wavelength lines with different sensitivities. K2S2O7, Al2O3 and NH4I were used as buffer agent, and Ge was used as internal standard. The sample was loaded by deep-hole electrode. This method effectively broadened the measuring range of tin. The content of tin in range of 0.001%-10% in ore could be determined. This method was applied to the determination of standard sample and unknown sample. The results were compared and verified with iodometry. It was found that, the determination results were consistent with those obtained by chemical method. The relative standard deviation (RSD, n=12) was less than 5%. This method could be used in the determination of tin in various ores with different content range.


La M.-J.,Northwest Normal University | La M.-J.,Lanzhou Testing and Quality Supervision Center for Geological and Mineral Products | Wang Y.-C.,Northwest Normal University | Wang C.-L.,Northwest Normal University | And 4 more authors.
Computational and Theoretical Chemistry | Year: 2012

The different potential energy surfaces (PESs) of Ni+ (2D, 3d9) with butanone in gas phase have been systematically explored by density functional theory (DFT). Two parallel decomposition reaction mechanisms have been identified. The course that the Ni+ inserts into the σ-bond of the CC2H5 or CCH3 leading to the CC bond activation has been analyzed using the natural bond orbital (NBO). Finally, the conclusion of the theory calculation was consistent with the experimental results which provided by the Darrin J. Bellert group in 2011 that three neutral organic molecule products (ethylene, acetaldehyde and methane) were obtained. © 2011 Elsevier B.V..


Liu J.-B.,Lanzhou Testing and Quality Supervision Center for Geological and Mineral Products | Dang L.,Lanzhou Testing and Quality Supervision Center for Geological and Mineral Products | He Z.-Y.,Lanzhou Testing and Quality Supervision Center for Geological and Mineral Products
Yejin Fenxi/Metallurgical Analysis | Year: 2013

After the sample was melted with mixed flux (Li2B4O7-LiBO2-LiF), seventeen major and minor components in manganese ore, including Mn, TFe, SiO2, Al2O3, CaO, MgO, K2O, Na2O, TiO2, P, S, BaO, Cu, Co, Ni, V and As, were determined by X-ray fluorescence spectrometry. S and As could be converted to stable salt during pre-oxidation with NH4NO3 as oxidizing agent and Li2CO3 as protective agent. Consequently, the volatilization loss of S and As in sample preparation by fusion could be prevented. Cr2O3 was added and used as internal standard for Mn to eliminate the matrix effect on the determination of Mn. The precision test was performed with manganese ore synthetic reference samples. The relative standard deviation (RSD, n=12) was less than 10%. The accuracy test was conducted with manganese ore reference samples and synthetic samples. The results were consistent with the certified values and those obtained by wet method.

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