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Mineral’nyye Vody, Russia

Stoyanova T.V.,National University of Mineral Resources | Tomaev V.V.,Saint Petersburg State University | Stoyanov N.D.,LED Microsensor NT LLC | Andreev S.K.,Bulgarian Academy of Science
Journal of Physics: Conference Series | Year: 2014

In this paper we present an approach which allows to increase the sensitivity of the sensors at room temperature. Field effect transistors with SnO2 gate in combination with optical activation of the adsorption centres on the surface were utilized. Studies of photosensitivity were carried out using a set of LEDs in the visible spectral range by the method of impedance spectroscopy. Optical activation of the adsorption centres in the SnO2 gate leads to the additional accumulation of positive charges on top of the gate H+. Positive charge caused broadening of the channel in MOSFET sensor, resulting to lower real component of the impedance. These results show that optical activation allows to detect significantly lower concentrations of the hydrogen contained gases. © Published under licence by IOP Publishing Ltd. Source

Abdul-Latif B.L.,National University of Mineral Resources | Kwesi D.C.,National University of Mineral Resources | Ernest A.,University of Petroleum and Minerals | Fahd K.,University of Petroleum and Minerals
Society of Petroleum Engineers - SPE Russian Petroleum Technology Conference | Year: 2015

An increase in the demand for gas in this current generation and the availability of several technologies including horizontal drilling technology has opened up the development of tight gas reservoirs throughout the globe. Efficiently draining the reservoir using hydraulic fracturing strongly depends on well spacing, especially for low permeability reservoirs. Most of the majority of work done by petroleum industries in the world especially in the Russian Federation to find the optimum well spacing is based on economic and technical considerations. Key factors influencing performance of gas and gas condensate reservoirs include controllable and uncontrollable factors. Uncontrollable factors include porosity, water saturation, net-to-gross, initial pressure, permeability, natural fractures and fluid properties. The most relevant parameters among the controllable factors to consider for optimizing well spacing in gas and gas condensate wells are well design variations, well placement, surface facilities design, completion technologies and operating conditions which also include parameters such as the reservoir thickness, permeability anisotropy ratio, fracture conductivity, induced fractures and fracture half-lengths. Due to the dearth of interference test data in gas wells and the inaccuracy of analytical solutions, numerical simulation is the most suitable approach for optimizing spacing in gas wells. In finding the optimum well spacing, several simulation runs are carried out for a real range of well and reservoir variables. The results are then tabulated and translated into a 15 and 45-year cumulative production as a function of well spacing, with the results indicating that lower permeability reservoirs require closer well spacing. In the case of a large number of long fractures, wells need to be placed further away from each to reduce well interference. This paper outlines the outcomes of optimization studies on well spacing in which both analytical and numerical tools were used in the presented workflow for several development scenarios in the gas and gas-condensate reservoir environments. Copyright 2015, Society of Petroleum Engineers. Source

Alekseev V.I.,National University of Mineral Resources | Marin Y.B.,National University of Mineral Resources
Geology of Ore Deposits | Year: 2013

An assemblage of chernovite-(Y), As-bearing thorite, rooseveltite, and Cu and Fe arsenates has been revealed in Li-F granites, ongonites, and greisens of the Far East. The formation sequence of the above minerals is described in this paper. Chernovite-(Y) is a product of autometasomatic alteration of Li-F granite and ongonite, whereas other arsenates and As-thorite are products of greisenization. © 2013 Pleiades Publishing, Ltd. Source

Kazanin O.I.,National University of Mineral Resources | Mustafin M.G.,National University of Mineral Resources | Meshkov A.A.,VAT SUEK Kuzbass | Sidorenko A.A.,National University of Mineral Resources
Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu | Year: 2015

Purpose: Determination of parameters of the effective close multiple-seam mining technologies in the conditions of a negative effect of mining operations on a daily surface. Methodology: The complex method, which includes analysis and summary of the published results of undermined by intensive multi-seam mining surface subsidence researches is used; field studies of undermined surface subsidence processes; field studies of undermined massive geological structure by audio-magneto-telluric sounding method; experimental-analytical researches by finite element method. Findings: The mechanism of the daily surface failures formation during coal seam mining at depths, almost by 100 times exceeding the mining seam thickness is shown. The recommendations to provide the economic effectiveness of coal mining in conditions of negative effect of underground mining operations on a daily surface are given. Originality: The conditions of closing of the daily surface cracks and failures caused by flat seam longwall mining are determined. Dependence between damage caused by the coal reserves losses, costs of surface reclamation and various parameters of mining system for conditions of the VAT "SUEK-Kuzbass" coal mines is determined. Practical value: It is established that existence of the thick and strong sandstone layers in covering rock mass is the main factor that determines the daily surface deformations character when the depths of mining exceeds the 20 thickness of seam, mined with using longwall system with leaving between longwall panels no extractable chain pillars. Technological conditions of the surface cracks and failures closing, which were caused by consecutive flat coal seams mining in VAT "SUEK-Kuzbass" coal mines, are determined. The criteria for the coal mining technological schemes parameters choice in the conditions of a negative effect of the mining operations on a daily surface are offered. Methodical recommendations for the choice of coal mining technological schemes parameters in the conditions of a negative effect of underground mining operations on a daily surface are developed. Source

Alekseev V.I.,National University of Mineral Resources | Marin Y.B.,National University of Mineral Resources
Geology of Ore Deposits | Year: 2014

Tourmaline schlieren in pegmatoids and host granites are widespread in Cretaceous granitoid plutons occurring in tin districts of eastern Russia. These schlieren were formed under the action of fluoricboron fluids, which are considered to be forerunners of rare-metal granite magmatism. The tourmaline schlieren in adamellites, biotite, and two-mica granites are reliable attributes of intrusive series completed by emplacement of ore-bearing Li-F granites. © 2014, Pleiades Publishing, Ltd. Source

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