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Currently, the coal mine fire monitoring system has achieved separate monitoring of some indicators such as the iconic gases, temperature, smoke, and flame of coal spontaneous combustion in mines.But the system has not effectively, comprehensively, and uniformly monitored the factors related to coal mine fires. In order to solve this problem, potential risk factors of coal mine fires are analyzed from two aspects: internal and external factors. A method of monitoring fire situation in different sources and areas is proposed. In terms of internal fires, monitoring is mainly carried out on goaf areas, enclosed goaf areas, and artificial natural fire observation points that are prone to fires. In terms of external fires, monitoring is mainly carried out on the mechanical and electrical chambers and their distribution points, belt conveyor systems, cables, and other aspects. A monitoring index system for coal mine fire sources and areas has been established. The system regularly collects or updates fire feature parameter data through manual or online monitoring. According to the data collection method and impact degree, fire monitoring indicators are divided into dynamic indicators, static indicators, and related indicators. The overall architecture and business process of a fire intelligent warning system is designed. The system uses a warning method based on multi index joint logical reasoning to achieve internal fire warning, and uses a multi parameter fusion warning method based on D-S evidence theory to achieve external fire warning. The on-site test results show that the fire intelligent warning system has achieved effective monitoring and warning of mine fires, with a visual display function of a coal mine fire risk warning 'one picture'. The system has a fire intelligent simulation demonstration function and a dynamic planning function for disaster avoidance routes.

The current oil recovery of the Lucaogou shale oil reservoir is predicted to be about 7.2%. It is crucial to explore improved oil recovery (IOR) technologies, and further experimental and field research needs to be conducted to study the complex mechanism. In this study, laboratory experiments were carried out to investigate the performance of one-step and multi-step depletion, CO2 huff-n-puff, and surfactant imbibition based on nuclear magnetic resonance (NMR). The sweep efficiencies were assessed via NMR imaging. In addition, hybrid methods of combining surfactant with CO2 huff-n-puff and the performance of injection sequence on oil recovery were investigated. The experimental results indicate that oil recoveries of depletion development at different initial pressures range from 4% to 11%. CO2 huff-n-puff has the highest oil recovery (30.45% and 40.70%), followed by surfactant imbibition (24.24% and 20.89%). Pore size distribution is an important factor. After three more cycles of surfactant imbibition and CO2 huff-n-puff, the oil recovery can be increased by 11.27% and 26.27%, respectively. Surfactant imbibition after CO2 huff-n-puff shows a viable method. Our study can provide guidance and theoretical support for shale oil development in the Lucaogou shale oil reservoir. [ABSTRACT FROM AUTHOR]

Both theoretical and experimental approaches are utilized to investigate the fluorescence mechanism of B‐site substituted Cs2XCl6 (A2BX6‐type perovskite, X = Sn, Hf, Zr, Ti), aiming to enhance the luminescence and tune the emission wavelengths. Using Te‐monosubstituted Cs2SnCl6 as a model system, thecomputational discovery that the introduction of out‐gap and in‐gap bands by Te can significantly enhance its transition dipole moment is reported. This is further experimentally confirmed, showing a single emission peak resulting from the radiative transition between the out‐gap and in‐gap bands. The broadening of the emission peak is attributed to self‐trapped exciton (STE), while additional absorption/excitation peaks arise from composition segregation. Additionally, the high‐throughput first‐principles calculations indicate that substituting B‐sites of Cs2XCl6 with Se, Te, Po, As, Sb, and Bi may also significantly enhance their light emission with the introduced bands. Thus, fine‐tuning the emission wavelengths by controlling the position of out‐gap and in‐gap bands through cation selection is proposed. Furthermore, tunable white‐light emission is achieved with excellent color stability by adjusting the Te and Bi composition in co‐substituted Cs2SnCl6 material. The findings highlight the potential of utilizing out‐gap and in‐gap bands to tune luminescence in this perovskite family for advanced device applications, including white‐light‐emitting diodes (WLEDs). [ABSTRACT FROM AUTHOR]

The special sedimentary environments of conglomerate reservoir lead to pore structure characteristics of complex modal, and the reservoir seepage system is mainly in the “sparse reticular-non reticular” flow pattern. As a result, the study on microscopic seepage mechanism of water flooding and polymer flooding and their differences becomes the complex part and key to enhance oil recovery. In this paper, the actual core samples from conglomerate reservoir in Karamay oilfield are selected as research objects to explore microscopic seepage mechanisms of water flooding and polymer flooding for hydrophilic rock as well as lipophilic rock by applying the Computed Tomography (CT) scanning technology. After that, the final oil recovery models of conglomerate reservoir are established in two displacement methods based on the influence analysis of oil displacement efficiency. Experimental results show that the seepage mechanisms of water flooding and polymer flooding for hydrophilic rock are all mainly “crawling” displacement along the rock surface while the weak lipophilic rocks are all mainly “inrushing” displacement along pore central. Due to the different seepage mechanisms among the water flooding and the polymer flooding, the residual oil remains in hydrophilic rock after water flooding process is mainly distributed in fine throats and pore interchange. These residual oil are cut into small droplets under the influence of polymer solution with stronger shearing drag effect. Then, those small droplets pass well through narrow throats and move forward along with the polymer solution flow, which makes enhancing oil recovery to be possible. The residual oil in weak lipophilic rock after water flooding mainly distributed on the rock particle surface and formed oil film and fine pore-throat. The polymer solution with stronger shear stress makes these oil films to carry away from particle surface in two ways such as bridge connection and forming oil silk. Because of the essential attributes differences between polymer solution and injection water solution, the impact of Complex Modal Pore Structure (CMPS) on the polymer solution displacement and seepage is much smaller than on water flooding solution. Therefore, for the two types of conglomerate rocks with different wettability, the pore structure is the main controlling factor of water flooding efficiency, while reservoir properties oil saturation, and other factors have smaller influence on flooding efficiency although the polymer flooding efficiency has a good correlation with remaining oil saturation after water flooding. Based on the analysis on oil displacement efficiency factors, the parameters of water flooding index and remaining oil saturation after water flooding are used to establish respectively calculation models of oil recovery in water flooding stage and polymer flooding stage for conglomerate reservoir. These models are able to calculate the oil recovery values of this area controlled by single well control, and further to determine the oil recovery of whole reservoir in different displacement stages by leveraging interpolation simulation methods, thereby providing more accurate geological parameters for the fine design of displacement oil program.

Targeting the conglomerate reservoir of the Lower Karamay Formation in the Middle District No.6 of Karamay Oilfield, based on the research of conglomerate reservoir characteristics and flow mechanism, laboratory experiments were conducted to study the pore production characteristics during water-oil displacement and imbibition and analyze the effect of pore structure on oil displacement efficiency, the microcosmic distribution of remaining oil and the influence of long term water flooding on reservoir pore structure. The results show that the remaining oil saturation is high, while the remaining oil is mainly in small sized pores. During the water-oil displacement, the preferential producing pores are super large pores; large and middle pores make great contributions to recovery. During the imbibition, the preferential producing pores are small pores and imbibition effect largely depends on middle and small pores. The oil displacement efficiency and microcosmic remaining oil distribution are mainly affected by pore structure. After water flooding over a long period of time, the interstitial materials expand, decentralize, move, and get eroded; large pores and throats increase; the connectivity becomes better; and the micro-heterogeneity gets more serious. 摘要: 以克拉玛依油田六-区下克拉玛依组砾岩储集层为研究对象 从砾岩储集层特征分析和渗流机理研究着手 通过室内实验 研究砾岩储集层水驱油和渗吸过程-微观孔隙动用规律 分析了孔隙结构与驱油效率关系 研究微观剩余油分布特征和长期水驱油对储集层孔隙结构的影响。研究表明目前剩余油饱和度较高 但剩余油主要分布于小孔隙之- 水驱过程- 优先动用的是超大孔隙 对采出程度起主要贡献的是-大孔隙 渗吸过程- 优先动用的是小孔隙 对渗吸作用起主要贡献的是-小孔隙 孔隙结构是影响驱油效率和微观剩余油分布的关键因素 长期水驱后 孔隙-填隙物发生膨胀、分散、运移和溶蚀 大孔道增多 连通性变好 储集层微观非均质性进一步增强。图11表5参21 关键词砾岩储集层 驱油效率 孔隙结构 核磁共振 剩余油 渗吸-图分类号TE311; TE341 文献标识码A Key words: conglomerate reservoir, oil displacement efficiency, pore structure, nuclear magnetic resonance, remaining oil, imbibition